granicus.if.org Git - postgresql/blob - src/backend/parser/parse_relation.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * parse_relation.c
   4  *        parser support routines dealing with relations
   5  *
   6  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.148 2010/01/02 16:57:50 momjian Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include <ctype.h>
  18
  19 #include "access/heapam.h"
  20 #include "access/sysattr.h"
  21 #include "catalog/heap.h"
  22 #include "catalog/namespace.h"
  23 #include "catalog/pg_type.h"
  24 #include "funcapi.h"
  25 #include "nodes/makefuncs.h"
  26 #include "nodes/nodeFuncs.h"
  27 #include "parser/parsetree.h"
  28 #include "parser/parse_relation.h"
  29 #include "parser/parse_type.h"
  30 #include "utils/builtins.h"
  31 #include "utils/lsyscache.h"
  32 #include "utils/syscache.h"
  33
  34
  35 static RangeTblEntry *scanNameSpaceForRefname(ParseState *pstate,
  36                                                 const char *refname, int location);
  37 static RangeTblEntry *scanNameSpaceForRelid(ParseState *pstate, Oid relid,
  38                                           int location);
  39 static void markRTEForSelectPriv(ParseState *pstate, RangeTblEntry *rte,
  40                                          int rtindex, AttrNumber col);
  41 static void expandRelation(Oid relid, Alias *eref,
  42                            int rtindex, int sublevels_up,
  43                            int location, bool include_dropped,
  44                            List **colnames, List **colvars);
  45 static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
  46                                 int rtindex, int sublevels_up,
  47                                 int location, bool include_dropped,
  48                                 List **colnames, List **colvars);
  49 static int      specialAttNum(const char *attname);
  50
  51
  52 /*
  53  * refnameRangeTblEntry
  54  *        Given a possibly-qualified refname, look to see if it matches any RTE.
  55  *        If so, return a pointer to the RangeTblEntry; else return NULL.
  56  *
  57  *        Optionally get RTE's nesting depth (0 = current) into *sublevels_up.
  58  *        If sublevels_up is NULL, only consider items at the current nesting
  59  *        level.
  60  *
  61  * An unqualified refname (schemaname == NULL) can match any RTE with matching
  62  * alias, or matching unqualified relname in the case of alias-less relation
  63  * RTEs.  It is possible that such a refname matches multiple RTEs in the
  64  * nearest nesting level that has a match; if so, we report an error via
  65  * ereport().
  66  *
  67  * A qualified refname (schemaname != NULL) can only match a relation RTE
  68  * that (a) has no alias and (b) is for the same relation identified by
  69  * schemaname.refname.  In this case we convert schemaname.refname to a
  70  * relation OID and search by relid, rather than by alias name.  This is
  71  * peculiar, but it's what SQL92 says to do.
  72  */
  73 RangeTblEntry *
  74 refnameRangeTblEntry(ParseState *pstate,
  75                                          const char *schemaname,
  76                                          const char *refname,
  77                                          int location,
  78                                          int *sublevels_up)
  79 {
  80         Oid                     relId = InvalidOid;
  81
  82         if (sublevels_up)
  83                 *sublevels_up = 0;
  84
  85         if (schemaname != NULL)
  86         {
  87                 Oid                     namespaceId;
  88
  89                 /*
  90                  * We can use LookupNamespaceNoError() here because we are only
  91                  * interested in finding existing RTEs.  Checking USAGE permission
  92                  * on the schema is unnecessary since it would have already been
  93                  * checked when the RTE was made.  Furthermore, we want to report
  94                  * "RTE not found", not "no permissions for schema", if the name
  95                  * happens to match a schema name the user hasn't got access to.
  96                  */
  97                 namespaceId = LookupNamespaceNoError(schemaname);
  98                 if (!OidIsValid(relId))
  99                         return NULL;
 100                 relId = get_relname_relid(refname, namespaceId);
 101                 if (!OidIsValid(relId))
 102                         return NULL;
 103         }
 104
 105         while (pstate != NULL)
 106         {
 107                 RangeTblEntry *result;
 108
 109                 if (OidIsValid(relId))
 110                         result = scanNameSpaceForRelid(pstate, relId, location);
 111                 else
 112                         result = scanNameSpaceForRefname(pstate, refname, location);
 113
 114                 if (result)
 115                         return result;
 116
 117                 if (sublevels_up)
 118                         (*sublevels_up)++;
 119                 else
 120                         break;
 121
 122                 pstate = pstate->parentParseState;
 123         }
 124         return NULL;
 125 }
 126
 127 /*
 128  * Search the query's table namespace for an RTE matching the
 129  * given unqualified refname.  Return the RTE if a unique match, or NULL
 130  * if no match.  Raise error if multiple matches.
 131  */
 132 static RangeTblEntry *
 133 scanNameSpaceForRefname(ParseState *pstate, const char *refname, int location)
 134 {
 135         RangeTblEntry *result = NULL;
 136         ListCell   *l;
 137
 138         foreach(l, pstate->p_relnamespace)
 139         {
 140                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 141
 142                 if (strcmp(rte->eref->aliasname, refname) == 0)
 143                 {
 144                         if (result)
 145                                 ereport(ERROR,
 146                                                 (errcode(ERRCODE_AMBIGUOUS_ALIAS),
 147                                                  errmsg("table reference \"%s\" is ambiguous",
 148                                                                 refname),
 149                                                  parser_errposition(pstate, location)));
 150                         result = rte;
 151                 }
 152         }
 153         return result;
 154 }
 155
 156 /*
 157  * Search the query's table namespace for a relation RTE matching the
 158  * given relation OID.  Return the RTE if a unique match, or NULL
 159  * if no match.  Raise error if multiple matches (which shouldn't
 160  * happen if the namespace was checked correctly when it was created).
 161  *
 162  * See the comments for refnameRangeTblEntry to understand why this
 163  * acts the way it does.
 164  */
 165 static RangeTblEntry *
 166 scanNameSpaceForRelid(ParseState *pstate, Oid relid, int location)
 167 {
 168         RangeTblEntry *result = NULL;
 169         ListCell   *l;
 170
 171         foreach(l, pstate->p_relnamespace)
 172         {
 173                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 174
 175                 /* yes, the test for alias == NULL should be there... */
 176                 if (rte->rtekind == RTE_RELATION &&
 177                         rte->relid == relid &&
 178                         rte->alias == NULL)
 179                 {
 180                         if (result)
 181                                 ereport(ERROR,
 182                                                 (errcode(ERRCODE_AMBIGUOUS_ALIAS),
 183                                                  errmsg("table reference %u is ambiguous",
 184                                                                 relid),
 185                                                  parser_errposition(pstate, location)));
 186                         result = rte;
 187                 }
 188         }
 189         return result;
 190 }
 191
 192 /*
 193  * Search the query's CTE namespace for a CTE matching the given unqualified
 194  * refname.  Return the CTE (and its levelsup count) if a match, or NULL
 195  * if no match.  We need not worry about multiple matches, since parse_cte.c
 196  * rejects WITH lists containing duplicate CTE names.
 197  */
 198 CommonTableExpr *
 199 scanNameSpaceForCTE(ParseState *pstate, const char *refname,
 200                                         Index *ctelevelsup)
 201 {
 202         Index           levelsup;
 203
 204         for (levelsup = 0;
 205                  pstate != NULL;
 206                  pstate = pstate->parentParseState, levelsup++)
 207         {
 208                 ListCell   *lc;
 209
 210                 foreach(lc, pstate->p_ctenamespace)
 211                 {
 212                         CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
 213
 214                         if (strcmp(cte->ctename, refname) == 0)
 215                         {
 216                                 *ctelevelsup = levelsup;
 217                                 return cte;
 218                         }
 219                 }
 220         }
 221         return NULL;
 222 }
 223
 224 /*
 225  * Search for a possible "future CTE", that is one that is not yet in scope
 226  * according to the WITH scoping rules.  This has nothing to do with valid
 227  * SQL semantics, but it's important for error reporting purposes.
 228  */
 229 static bool
 230 isFutureCTE(ParseState *pstate, const char *refname)
 231 {
 232         for (; pstate != NULL; pstate = pstate->parentParseState)
 233         {
 234                 ListCell   *lc;
 235
 236                 foreach(lc, pstate->p_future_ctes)
 237                 {
 238                         CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
 239
 240                         if (strcmp(cte->ctename, refname) == 0)
 241                                 return true;
 242                 }
 243         }
 244         return false;
 245 }
 246
 247 /*
 248  * searchRangeTable
 249  *        See if any RangeTblEntry could possibly match the RangeVar.
 250  *        If so, return a pointer to the RangeTblEntry; else return NULL.
 251  *
 252  * This is different from refnameRangeTblEntry in that it considers every
 253  * entry in the ParseState's rangetable(s), not only those that are currently
 254  * visible in the p_relnamespace lists.  This behavior is invalid per the SQL
 255  * spec, and it may give ambiguous results (there might be multiple equally
 256  * valid matches, but only one will be returned).  This must be used ONLY
 257  * as a heuristic in giving suitable error messages.  See errorMissingRTE.
 258  *
 259  * Notice that we consider both matches on actual relation (or CTE) name
 260  * and matches on alias.
 261  */
 262 static RangeTblEntry *
 263 searchRangeTable(ParseState *pstate, RangeVar *relation)
 264 {
 265         const char *refname = relation->relname;
 266         Oid                     relId = InvalidOid;
 267         CommonTableExpr *cte = NULL;
 268         Index           ctelevelsup = 0;
 269         Index           levelsup;
 270
 271         /*
 272          * If it's an unqualified name, check for possible CTE matches. A CTE
 273          * hides any real relation matches.  If no CTE, look for a matching
 274          * relation.
 275          */
 276         if (!relation->schemaname)
 277                 cte = scanNameSpaceForCTE(pstate, refname, &ctelevelsup);
 278         if (!cte)
 279                 relId = RangeVarGetRelid(relation, true);
 280
 281         /* Now look for RTEs matching either the relation/CTE or the alias */
 282         for (levelsup = 0;
 283                  pstate != NULL;
 284                  pstate = pstate->parentParseState, levelsup++)
 285         {
 286                 ListCell   *l;
 287
 288                 foreach(l, pstate->p_rtable)
 289                 {
 290                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 291
 292                         if (rte->rtekind == RTE_RELATION &&
 293                                 OidIsValid(relId) &&
 294                                 rte->relid == relId)
 295                                 return rte;
 296                         if (rte->rtekind == RTE_CTE &&
 297                                 cte != NULL &&
 298                                 rte->ctelevelsup + levelsup == ctelevelsup &&
 299                                 strcmp(rte->ctename, refname) == 0)
 300                                 return rte;
 301                         if (strcmp(rte->eref->aliasname, refname) == 0)
 302                                 return rte;
 303                 }
 304         }
 305         return NULL;
 306 }
 307
 308 /*
 309  * Check for relation-name conflicts between two relnamespace lists.
 310  * Raise an error if any is found.
 311  *
 312  * Note: we assume that each given argument does not contain conflicts
 313  * itself; we just want to know if the two can be merged together.
 314  *
 315  * Per SQL92, two alias-less plain relation RTEs do not conflict even if
 316  * they have the same eref->aliasname (ie, same relation name), if they
 317  * are for different relation OIDs (implying they are in different schemas).
 318  */
 319 void
 320 checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
 321                                                 List *namespace2)
 322 {
 323         ListCell   *l1;
 324
 325         foreach(l1, namespace1)
 326         {
 327                 RangeTblEntry *rte1 = (RangeTblEntry *) lfirst(l1);
 328                 const char *aliasname1 = rte1->eref->aliasname;
 329                 ListCell   *l2;
 330
 331                 foreach(l2, namespace2)
 332                 {
 333                         RangeTblEntry *rte2 = (RangeTblEntry *) lfirst(l2);
 334
 335                         if (strcmp(rte2->eref->aliasname, aliasname1) != 0)
 336                                 continue;               /* definitely no conflict */
 337                         if (rte1->rtekind == RTE_RELATION && rte1->alias == NULL &&
 338                                 rte2->rtekind == RTE_RELATION && rte2->alias == NULL &&
 339                                 rte1->relid != rte2->relid)
 340                                 continue;               /* no conflict per SQL92 rule */
 341                         ereport(ERROR,
 342                                         (errcode(ERRCODE_DUPLICATE_ALIAS),
 343                                          errmsg("table name \"%s\" specified more than once",
 344                                                         aliasname1)));
 345                 }
 346         }
 347 }
 348
 349 /*
 350  * given an RTE, return RT index (starting with 1) of the entry,
 351  * and optionally get its nesting depth (0 = current).  If sublevels_up
 352  * is NULL, only consider rels at the current nesting level.
 353  * Raises error if RTE not found.
 354  */
 355 int
 356 RTERangeTablePosn(ParseState *pstate, RangeTblEntry *rte, int *sublevels_up)
 357 {
 358         int                     index;
 359         ListCell   *l;
 360
 361         if (sublevels_up)
 362                 *sublevels_up = 0;
 363
 364         while (pstate != NULL)
 365         {
 366                 index = 1;
 367                 foreach(l, pstate->p_rtable)
 368                 {
 369                         if (rte == (RangeTblEntry *) lfirst(l))
 370                                 return index;
 371                         index++;
 372                 }
 373                 pstate = pstate->parentParseState;
 374                 if (sublevels_up)
 375                         (*sublevels_up)++;
 376                 else
 377                         break;
 378         }
 379
 380         elog(ERROR, "RTE not found (internal error)");
 381         return 0;                                       /* keep compiler quiet */
 382 }
 383
 384 /*
 385  * Given an RT index and nesting depth, find the corresponding RTE.
 386  * This is the inverse of RTERangeTablePosn.
 387  */
 388 RangeTblEntry *
 389 GetRTEByRangeTablePosn(ParseState *pstate,
 390                                            int varno,
 391                                            int sublevels_up)
 392 {
 393         while (sublevels_up-- > 0)
 394         {
 395                 pstate = pstate->parentParseState;
 396                 Assert(pstate != NULL);
 397         }
 398         Assert(varno > 0 && varno <= list_length(pstate->p_rtable));
 399         return rt_fetch(varno, pstate->p_rtable);
 400 }
 401
 402 /*
 403  * Fetch the CTE for a CTE-reference RTE.
 404  *
 405  * rtelevelsup is the number of query levels above the given pstate that the
 406  * RTE came from.  Callers that don't have this information readily available
 407  * may pass -1 instead.
 408  */
 409 CommonTableExpr *
 410 GetCTEForRTE(ParseState *pstate, RangeTblEntry *rte, int rtelevelsup)
 411 {
 412         Index           levelsup;
 413         ListCell   *lc;
 414
 415         /* Determine RTE's levelsup if caller didn't know it */
 416         if (rtelevelsup < 0)
 417                 (void) RTERangeTablePosn(pstate, rte, &rtelevelsup);
 418
 419         Assert(rte->rtekind == RTE_CTE);
 420         levelsup = rte->ctelevelsup + rtelevelsup;
 421         while (levelsup-- > 0)
 422         {
 423                 pstate = pstate->parentParseState;
 424                 if (!pstate)                    /* shouldn't happen */
 425                         elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
 426         }
 427         foreach(lc, pstate->p_ctenamespace)
 428         {
 429                 CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
 430
 431                 if (strcmp(cte->ctename, rte->ctename) == 0)
 432                         return cte;
 433         }
 434         /* shouldn't happen */
 435         elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
 436         return NULL;                            /* keep compiler quiet */
 437 }
 438
 439 /*
 440  * scanRTEForColumn
 441  *        Search the column names of a single RTE for the given name.
 442  *        If found, return an appropriate Var node, else return NULL.
 443  *        If the name proves ambiguous within this RTE, raise error.
 444  *
 445  * Side effect: if we find a match, mark the RTE as requiring read access
 446  * for the column.
 447  */
 448 Node *
 449 scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte, char *colname,
 450                                  int location)
 451 {
 452         Node       *result = NULL;
 453         int                     attnum = 0;
 454         Var                *var;
 455         ListCell   *c;
 456
 457         /*
 458          * Scan the user column names (or aliases) for a match. Complain if
 459          * multiple matches.
 460          *
 461          * Note: eref->colnames may include entries for dropped columns, but those
 462          * will be empty strings that cannot match any legal SQL identifier, so we
 463          * don't bother to test for that case here.
 464          *
 465          * Should this somehow go wrong and we try to access a dropped column,
 466          * we'll still catch it by virtue of the checks in
 467          * get_rte_attribute_type(), which is called by make_var().  That routine
 468          * has to do a cache lookup anyway, so the check there is cheap.
 469          */
 470         foreach(c, rte->eref->colnames)
 471         {
 472                 attnum++;
 473                 if (strcmp(strVal(lfirst(c)), colname) == 0)
 474                 {
 475                         if (result)
 476                                 ereport(ERROR,
 477                                                 (errcode(ERRCODE_AMBIGUOUS_COLUMN),
 478                                                  errmsg("column reference \"%s\" is ambiguous",
 479                                                                 colname),
 480                                                  parser_errposition(pstate, location)));
 481                         var = make_var(pstate, rte, attnum, location);
 482                         /* Require read access to the column */
 483                         markVarForSelectPriv(pstate, var, rte);
 484                         result = (Node *) var;
 485                 }
 486         }
 487
 488         /*
 489          * If we have a unique match, return it.  Note that this allows a user
 490          * alias to override a system column name (such as OID) without error.
 491          */
 492         if (result)
 493                 return result;
 494
 495         /*
 496          * If the RTE represents a real table, consider system column names.
 497          */
 498         if (rte->rtekind == RTE_RELATION)
 499         {
 500                 /* quick check to see if name could be a system column */
 501                 attnum = specialAttNum(colname);
 502                 if (attnum != InvalidAttrNumber)
 503                 {
 504                         /* now check to see if column actually is defined */
 505                         if (SearchSysCacheExists(ATTNUM,
 506                                                                          ObjectIdGetDatum(rte->relid),
 507                                                                          Int16GetDatum(attnum),
 508                                                                          0, 0))
 509                         {
 510                                 var = make_var(pstate, rte, attnum, location);
 511                                 /* Require read access to the column */
 512                                 markVarForSelectPriv(pstate, var, rte);
 513                                 result = (Node *) var;
 514                         }
 515                 }
 516         }
 517
 518         return result;
 519 }
 520
 521 /*
 522  * colNameToVar
 523  *        Search for an unqualified column name.
 524  *        If found, return the appropriate Var node (or expression).
 525  *        If not found, return NULL.  If the name proves ambiguous, raise error.
 526  *        If localonly is true, only names in the innermost query are considered.
 527  */
 528 Node *
 529 colNameToVar(ParseState *pstate, char *colname, bool localonly,
 530                          int location)
 531 {
 532         Node       *result = NULL;
 533         ParseState *orig_pstate = pstate;
 534
 535         while (pstate != NULL)
 536         {
 537                 ListCell   *l;
 538
 539                 foreach(l, pstate->p_varnamespace)
 540                 {
 541                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 542                         Node       *newresult;
 543
 544                         /* use orig_pstate here to get the right sublevels_up */
 545                         newresult = scanRTEForColumn(orig_pstate, rte, colname, location);
 546
 547                         if (newresult)
 548                         {
 549                                 if (result)
 550                                         ereport(ERROR,
 551                                                         (errcode(ERRCODE_AMBIGUOUS_COLUMN),
 552                                                          errmsg("column reference \"%s\" is ambiguous",
 553                                                                         colname),
 554                                                          parser_errposition(orig_pstate, location)));
 555                                 result = newresult;
 556                         }
 557                 }
 558
 559                 if (result != NULL || localonly)
 560                         break;                          /* found, or don't want to look at parent */
 561
 562                 pstate = pstate->parentParseState;
 563         }
 564
 565         return result;
 566 }
 567
 568 /*
 569  * markRTEForSelectPriv
 570  *         Mark the specified column of an RTE as requiring SELECT privilege
 571  *
 572  * col == InvalidAttrNumber means a "whole row" reference
 573  *
 574  * The caller should pass the actual RTE if it has it handy; otherwise pass
 575  * NULL, and we'll look it up here.  (This uglification of the API is
 576  * worthwhile because nearly all external callers have the RTE at hand.)
 577  */
 578 static void
 579 markRTEForSelectPriv(ParseState *pstate, RangeTblEntry *rte,
 580                                          int rtindex, AttrNumber col)
 581 {
 582         if (rte == NULL)
 583                 rte = rt_fetch(rtindex, pstate->p_rtable);
 584
 585         if (rte->rtekind == RTE_RELATION)
 586         {
 587                 /* Make sure the rel as a whole is marked for SELECT access */
 588                 rte->requiredPerms |= ACL_SELECT;
 589                 /* Must offset the attnum to fit in a bitmapset */
 590                 rte->selectedCols = bms_add_member(rte->selectedCols,
 591                                                                    col - FirstLowInvalidHeapAttributeNumber);
 592         }
 593         else if (rte->rtekind == RTE_JOIN)
 594         {
 595                 if (col == InvalidAttrNumber)
 596                 {
 597                         /*
 598                          * A whole-row reference to a join has to be treated as whole-row
 599                          * references to the two inputs.
 600                          */
 601                         JoinExpr   *j;
 602
 603                         if (rtindex > 0 && rtindex <= list_length(pstate->p_joinexprs))
 604                                 j = (JoinExpr *) list_nth(pstate->p_joinexprs, rtindex - 1);
 605                         else
 606                                 j = NULL;
 607                         if (j == NULL)
 608                                 elog(ERROR, "could not find JoinExpr for whole-row reference");
 609                         Assert(IsA(j, JoinExpr));
 610
 611                         /* Note: we can't see FromExpr here */
 612                         if (IsA(j->larg, RangeTblRef))
 613                         {
 614                                 int                     varno = ((RangeTblRef *) j->larg)->rtindex;
 615
 616                                 markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
 617                         }
 618                         else if (IsA(j->larg, JoinExpr))
 619                         {
 620                                 int                     varno = ((JoinExpr *) j->larg)->rtindex;
 621
 622                                 markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
 623                         }
 624                         else
 625                                 elog(ERROR, "unrecognized node type: %d",
 626                                          (int) nodeTag(j->larg));
 627                         if (IsA(j->rarg, RangeTblRef))
 628                         {
 629                                 int                     varno = ((RangeTblRef *) j->rarg)->rtindex;
 630
 631                                 markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
 632                         }
 633                         else if (IsA(j->rarg, JoinExpr))
 634                         {
 635                                 int                     varno = ((JoinExpr *) j->rarg)->rtindex;
 636
 637                                 markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
 638                         }
 639                         else
 640                                 elog(ERROR, "unrecognized node type: %d",
 641                                          (int) nodeTag(j->rarg));
 642                 }
 643                 else
 644                 {
 645                         /*
 646                          * Regular join attribute, look at the alias-variable list.
 647                          *
 648                          * The aliasvar could be either a Var or a COALESCE expression,
 649                          * but in the latter case we should already have marked the two
 650                          * referent variables as being selected, due to their use in the
 651                          * JOIN clause.  So we need only be concerned with the simple Var
 652                          * case.
 653                          */
 654                         Var                *aliasvar;
 655
 656                         Assert(col > 0 && col <= list_length(rte->joinaliasvars));
 657                         aliasvar = (Var *) list_nth(rte->joinaliasvars, col - 1);
 658                         if (IsA(aliasvar, Var))
 659                                 markVarForSelectPriv(pstate, aliasvar, NULL);
 660                 }
 661         }
 662         /* other RTE types don't require privilege marking */
 663 }
 664
 665 /*
 666  * markVarForSelectPriv
 667  *         Mark the RTE referenced by a Var as requiring SELECT privilege
 668  *
 669  * The caller should pass the Var's referenced RTE if it has it handy
 670  * (nearly all do); otherwise pass NULL.
 671  */
 672 void
 673 markVarForSelectPriv(ParseState *pstate, Var *var, RangeTblEntry *rte)
 674 {
 675         Index           lv;
 676
 677         Assert(IsA(var, Var));
 678         /* Find the appropriate pstate if it's an uplevel Var */
 679         for (lv = 0; lv < var->varlevelsup; lv++)
 680                 pstate = pstate->parentParseState;
 681         markRTEForSelectPriv(pstate, rte, var->varno, var->varattno);
 682 }
 683
 684 /*
 685  * buildRelationAliases
 686  *              Construct the eref column name list for a relation RTE.
 687  *              This code is also used for the case of a function RTE returning
 688  *              a named composite type.
 689  *
 690  * tupdesc: the physical column information
 691  * alias: the user-supplied alias, or NULL if none
 692  * eref: the eref Alias to store column names in
 693  *
 694  * eref->colnames is filled in.  Also, alias->colnames is rebuilt to insert
 695  * empty strings for any dropped columns, so that it will be one-to-one with
 696  * physical column numbers.
 697  */
 698 static void
 699 buildRelationAliases(TupleDesc tupdesc, Alias *alias, Alias *eref)
 700 {
 701         int                     maxattrs = tupdesc->natts;
 702         ListCell   *aliaslc;
 703         int                     numaliases;
 704         int                     varattno;
 705         int                     numdropped = 0;
 706
 707         Assert(eref->colnames == NIL);
 708
 709         if (alias)
 710         {
 711                 aliaslc = list_head(alias->colnames);
 712                 numaliases = list_length(alias->colnames);
 713                 /* We'll rebuild the alias colname list */
 714                 alias->colnames = NIL;
 715         }
 716         else
 717         {
 718                 aliaslc = NULL;
 719                 numaliases = 0;
 720         }
 721
 722         for (varattno = 0; varattno < maxattrs; varattno++)
 723         {
 724                 Form_pg_attribute attr = tupdesc->attrs[varattno];
 725                 Value      *attrname;
 726
 727                 if (attr->attisdropped)
 728                 {
 729                         /* Always insert an empty string for a dropped column */
 730                         attrname = makeString(pstrdup(""));
 731                         if (aliaslc)
 732                                 alias->colnames = lappend(alias->colnames, attrname);
 733                         numdropped++;
 734                 }
 735                 else if (aliaslc)
 736                 {
 737                         /* Use the next user-supplied alias */
 738                         attrname = (Value *) lfirst(aliaslc);
 739                         aliaslc = lnext(aliaslc);
 740                         alias->colnames = lappend(alias->colnames, attrname);
 741                 }
 742                 else
 743                 {
 744                         attrname = makeString(pstrdup(NameStr(attr->attname)));
 745                         /* we're done with the alias if any */
 746                 }
 747
 748                 eref->colnames = lappend(eref->colnames, attrname);
 749         }
 750
 751         /* Too many user-supplied aliases? */
 752         if (aliaslc)
 753                 ereport(ERROR,
 754                                 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
 755                                  errmsg("table \"%s\" has %d columns available but %d columns specified",
 756                                                 eref->aliasname, maxattrs - numdropped, numaliases)));
 757 }
 758
 759 /*
 760  * buildScalarFunctionAlias
 761  *              Construct the eref column name list for a function RTE,
 762  *              when the function returns a scalar type (not composite or RECORD).
 763  *
 764  * funcexpr: transformed expression tree for the function call
 765  * funcname: function name (used only for error message)
 766  * alias: the user-supplied alias, or NULL if none
 767  * eref: the eref Alias to store column names in
 768  *
 769  * eref->colnames is filled in.
 770  */
 771 static void
 772 buildScalarFunctionAlias(Node *funcexpr, char *funcname,
 773                                                  Alias *alias, Alias *eref)
 774 {
 775         char       *pname;
 776
 777         Assert(eref->colnames == NIL);
 778
 779         /* Use user-specified column alias if there is one. */
 780         if (alias && alias->colnames != NIL)
 781         {
 782                 if (list_length(alias->colnames) != 1)
 783                         ereport(ERROR,
 784                                         (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
 785                                   errmsg("too many column aliases specified for function %s",
 786                                                  funcname)));
 787                 eref->colnames = copyObject(alias->colnames);
 788                 return;
 789         }
 790
 791         /*
 792          * If the expression is a simple function call, and the function has a
 793          * single OUT parameter that is named, use the parameter's name.
 794          */
 795         if (funcexpr && IsA(funcexpr, FuncExpr))
 796         {
 797                 pname = get_func_result_name(((FuncExpr *) funcexpr)->funcid);
 798                 if (pname)
 799                 {
 800                         eref->colnames = list_make1(makeString(pname));
 801                         return;
 802                 }
 803         }
 804
 805         /*
 806          * Otherwise use the previously-determined alias (not necessarily the
 807          * function name!)
 808          */
 809         eref->colnames = list_make1(makeString(eref->aliasname));
 810 }
 811
 812 /*
 813  * Open a table during parse analysis
 814  *
 815  * This is essentially just the same as heap_openrv(), except that it caters
 816  * to some parser-specific error reporting needs, notably that it arranges
 817  * to include the RangeVar's parse location in any resulting error.
 818  *
 819  * Note: properly, lockmode should be declared LOCKMODE not int, but that
 820  * would require importing storage/lock.h into parse_relation.h.  Since
 821  * LOCKMODE is typedef'd as int anyway, that seems like overkill.
 822  */
 823 Relation
 824 parserOpenTable(ParseState *pstate, const RangeVar *relation, int lockmode)
 825 {
 826         Relation        rel;
 827         ParseCallbackState pcbstate;
 828
 829         setup_parser_errposition_callback(&pcbstate, pstate, relation->location);
 830         rel = try_heap_openrv(relation, lockmode);
 831         if (rel == NULL)
 832         {
 833                 if (relation->schemaname)
 834                         ereport(ERROR,
 835                                         (errcode(ERRCODE_UNDEFINED_TABLE),
 836                                          errmsg("relation \"%s.%s\" does not exist",
 837                                                         relation->schemaname, relation->relname)));
 838                 else
 839                 {
 840                         /*
 841                          * An unqualified name might have been meant as a reference to
 842                          * some not-yet-in-scope CTE.  The bare "does not exist" message
 843                          * has proven remarkably unhelpful for figuring out such problems,
 844                          * so we take pains to offer a specific hint.
 845                          */
 846                         if (isFutureCTE(pstate, relation->relname))
 847                                 ereport(ERROR,
 848                                                 (errcode(ERRCODE_UNDEFINED_TABLE),
 849                                                  errmsg("relation \"%s\" does not exist",
 850                                                                 relation->relname),
 851                                                  errdetail("There is a WITH item named \"%s\", but it cannot be referenced from this part of the query.",
 852                                                                    relation->relname),
 853                                                  errhint("Use WITH RECURSIVE, or re-order the WITH items to remove forward references.")));
 854                         else
 855                                 ereport(ERROR,
 856                                                 (errcode(ERRCODE_UNDEFINED_TABLE),
 857                                                  errmsg("relation \"%s\" does not exist",
 858                                                                 relation->relname)));
 859                 }
 860         }
 861         cancel_parser_errposition_callback(&pcbstate);
 862         return rel;
 863 }
 864
 865 /*
 866  * Add an entry for a relation to the pstate's range table (p_rtable).
 867  *
 868  * If pstate is NULL, we just build an RTE and return it without adding it
 869  * to an rtable list.
 870  *
 871  * Note: formerly this checked for refname conflicts, but that's wrong.
 872  * Caller is responsible for checking for conflicts in the appropriate scope.
 873  */
 874 RangeTblEntry *
 875 addRangeTableEntry(ParseState *pstate,
 876                                    RangeVar *relation,
 877                                    Alias *alias,
 878                                    bool inh,
 879                                    bool inFromCl)
 880 {
 881         RangeTblEntry *rte = makeNode(RangeTblEntry);
 882         char       *refname = alias ? alias->aliasname : relation->relname;
 883         LOCKMODE        lockmode;
 884         Relation        rel;
 885
 886         rte->rtekind = RTE_RELATION;
 887         rte->alias = alias;
 888
 889         /*
 890          * Get the rel's OID.  This access also ensures that we have an up-to-date
 891          * relcache entry for the rel.  Since this is typically the first access
 892          * to a rel in a statement, be careful to get the right access level
 893          * depending on whether we're doing SELECT FOR UPDATE/SHARE.
 894          */
 895         lockmode = isLockedRefname(pstate, refname) ? RowShareLock : AccessShareLock;
 896         rel = parserOpenTable(pstate, relation, lockmode);
 897         rte->relid = RelationGetRelid(rel);
 898
 899         /*
 900          * Build the list of effective column names using user-supplied aliases
 901          * and/or actual column names.
 902          */
 903         rte->eref = makeAlias(refname, NIL);
 904         buildRelationAliases(rel->rd_att, alias, rte->eref);
 905
 906         /*
 907          * Drop the rel refcount, but keep the access lock till end of transaction
 908          * so that the table can't be deleted or have its schema modified
 909          * underneath us.
 910          */
 911         heap_close(rel, NoLock);
 912
 913         /*----------
 914          * Flags:
 915          * - this RTE should be expanded to include descendant tables,
 916          * - this RTE is in the FROM clause,
 917          * - this RTE should be checked for appropriate access rights.
 918          *
 919          * The initial default on access checks is always check-for-READ-access,
 920          * which is the right thing for all except target tables.
 921          *----------
 922          */
 923         rte->inh = inh;
 924         rte->inFromCl = inFromCl;
 925
 926         rte->requiredPerms = ACL_SELECT;
 927         rte->checkAsUser = InvalidOid;          /* not set-uid by default, either */
 928         rte->selectedCols = NULL;
 929         rte->modifiedCols = NULL;
 930
 931         /*
 932          * Add completed RTE to pstate's range table list, but not to join list
 933          * nor namespace --- caller must do that if appropriate.
 934          */
 935         if (pstate != NULL)
 936                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
 937
 938         return rte;
 939 }
 940
 941 /*
 942  * Add an entry for a relation to the pstate's range table (p_rtable).
 943  *
 944  * This is just like addRangeTableEntry() except that it makes an RTE
 945  * given an already-open relation instead of a RangeVar reference.
 946  */
 947 RangeTblEntry *
 948 addRangeTableEntryForRelation(ParseState *pstate,
 949                                                           Relation rel,
 950                                                           Alias *alias,
 951                                                           bool inh,
 952                                                           bool inFromCl)
 953 {
 954         RangeTblEntry *rte = makeNode(RangeTblEntry);
 955         char       *refname = alias ? alias->aliasname : RelationGetRelationName(rel);
 956
 957         rte->rtekind = RTE_RELATION;
 958         rte->alias = alias;
 959         rte->relid = RelationGetRelid(rel);
 960
 961         /*
 962          * Build the list of effective column names using user-supplied aliases
 963          * and/or actual column names.
 964          */
 965         rte->eref = makeAlias(refname, NIL);
 966         buildRelationAliases(rel->rd_att, alias, rte->eref);
 967
 968         /*----------
 969          * Flags:
 970          * - this RTE should be expanded to include descendant tables,
 971          * - this RTE is in the FROM clause,
 972          * - this RTE should be checked for appropriate access rights.
 973          *
 974          * The initial default on access checks is always check-for-READ-access,
 975          * which is the right thing for all except target tables.
 976          *----------
 977          */
 978         rte->inh = inh;
 979         rte->inFromCl = inFromCl;
 980
 981         rte->requiredPerms = ACL_SELECT;
 982         rte->checkAsUser = InvalidOid;          /* not set-uid by default, either */
 983         rte->selectedCols = NULL;
 984         rte->modifiedCols = NULL;
 985
 986         /*
 987          * Add completed RTE to pstate's range table list, but not to join list
 988          * nor namespace --- caller must do that if appropriate.
 989          */
 990         if (pstate != NULL)
 991                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
 992
 993         return rte;
 994 }
 995
 996 /*
 997  * Add an entry for a subquery to the pstate's range table (p_rtable).
 998  *
 999  * This is just like addRangeTableEntry() except that it makes a subquery RTE.
1000  * Note that an alias clause *must* be supplied.
1001  */
1002 RangeTblEntry *
1003 addRangeTableEntryForSubquery(ParseState *pstate,
1004                                                           Query *subquery,
1005                                                           Alias *alias,
1006                                                           bool inFromCl)
1007 {
1008         RangeTblEntry *rte = makeNode(RangeTblEntry);
1009         char       *refname = alias->aliasname;
1010         Alias      *eref;
1011         int                     numaliases;
1012         int                     varattno;
1013         ListCell   *tlistitem;
1014
1015         rte->rtekind = RTE_SUBQUERY;
1016         rte->relid = InvalidOid;
1017         rte->subquery = subquery;
1018         rte->alias = alias;
1019
1020         eref = copyObject(alias);
1021         numaliases = list_length(eref->colnames);
1022
1023         /* fill in any unspecified alias columns */
1024         varattno = 0;
1025         foreach(tlistitem, subquery->targetList)
1026         {
1027                 TargetEntry *te = (TargetEntry *) lfirst(tlistitem);
1028
1029                 if (te->resjunk)
1030                         continue;
1031                 varattno++;
1032                 Assert(varattno == te->resno);
1033                 if (varattno > numaliases)
1034                 {
1035                         char       *attrname;
1036
1037                         attrname = pstrdup(te->resname);
1038                         eref->colnames = lappend(eref->colnames, makeString(attrname));
1039                 }
1040         }
1041         if (varattno < numaliases)
1042                 ereport(ERROR,
1043                                 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
1044                                  errmsg("table \"%s\" has %d columns available but %d columns specified",
1045                                                 refname, varattno, numaliases)));
1046
1047         rte->eref = eref;
1048
1049         /*----------
1050          * Flags:
1051          * - this RTE should be expanded to include descendant tables,
1052          * - this RTE is in the FROM clause,
1053          * - this RTE should be checked for appropriate access rights.
1054          *
1055          * Subqueries are never checked for access rights.
1056          *----------
1057          */
1058         rte->inh = false;                       /* never true for subqueries */
1059         rte->inFromCl = inFromCl;
1060
1061         rte->requiredPerms = 0;
1062         rte->checkAsUser = InvalidOid;
1063         rte->selectedCols = NULL;
1064         rte->modifiedCols = NULL;
1065
1066         /*
1067          * Add completed RTE to pstate's range table list, but not to join list
1068          * nor namespace --- caller must do that if appropriate.
1069          */
1070         if (pstate != NULL)
1071                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
1072
1073         return rte;
1074 }
1075
1076 /*
1077  * Add an entry for a function to the pstate's range table (p_rtable).
1078  *
1079  * This is just like addRangeTableEntry() except that it makes a function RTE.
1080  */
1081 RangeTblEntry *
1082 addRangeTableEntryForFunction(ParseState *pstate,
1083                                                           char *funcname,
1084                                                           Node *funcexpr,
1085                                                           RangeFunction *rangefunc,
1086                                                           bool inFromCl)
1087 {
1088         RangeTblEntry *rte = makeNode(RangeTblEntry);
1089         TypeFuncClass functypclass;
1090         Oid                     funcrettype;
1091         TupleDesc       tupdesc;
1092         Alias      *alias = rangefunc->alias;
1093         List       *coldeflist = rangefunc->coldeflist;
1094         Alias      *eref;
1095
1096         rte->rtekind = RTE_FUNCTION;
1097         rte->relid = InvalidOid;
1098         rte->subquery = NULL;
1099         rte->funcexpr = funcexpr;
1100         rte->funccoltypes = NIL;
1101         rte->funccoltypmods = NIL;
1102         rte->alias = alias;
1103
1104         eref = makeAlias(alias ? alias->aliasname : funcname, NIL);
1105         rte->eref = eref;
1106
1107         /*
1108          * Now determine if the function returns a simple or composite type.
1109          */
1110         functypclass = get_expr_result_type(funcexpr,
1111                                                                                 &funcrettype,
1112                                                                                 &tupdesc);
1113
1114         /*
1115          * A coldeflist is required if the function returns RECORD and hasn't got
1116          * a predetermined record type, and is prohibited otherwise.
1117          */
1118         if (coldeflist != NIL)
1119         {
1120                 if (functypclass != TYPEFUNC_RECORD)
1121                         ereport(ERROR,
1122                                         (errcode(ERRCODE_SYNTAX_ERROR),
1123                                          errmsg("a column definition list is only allowed for functions returning \"record\""),
1124                                          parser_errposition(pstate, exprLocation(funcexpr))));
1125         }
1126         else
1127         {
1128                 if (functypclass == TYPEFUNC_RECORD)
1129                         ereport(ERROR,
1130                                         (errcode(ERRCODE_SYNTAX_ERROR),
1131                                          errmsg("a column definition list is required for functions returning \"record\""),
1132                                          parser_errposition(pstate, exprLocation(funcexpr))));
1133         }
1134
1135         if (functypclass == TYPEFUNC_COMPOSITE)
1136         {
1137                 /* Composite data type, e.g. a table's row type */
1138                 Assert(tupdesc);
1139                 /* Build the column alias list */
1140                 buildRelationAliases(tupdesc, alias, eref);
1141         }
1142         else if (functypclass == TYPEFUNC_SCALAR)
1143         {
1144                 /* Base data type, i.e. scalar */
1145                 buildScalarFunctionAlias(funcexpr, funcname, alias, eref);
1146         }
1147         else if (functypclass == TYPEFUNC_RECORD)
1148         {
1149                 ListCell   *col;
1150
1151                 /*
1152                  * Use the column definition list to form the alias list and
1153                  * funccoltypes/funccoltypmods lists.
1154                  */
1155                 foreach(col, coldeflist)
1156                 {
1157                         ColumnDef  *n = (ColumnDef *) lfirst(col);
1158                         char       *attrname;
1159                         Oid                     attrtype;
1160                         int32           attrtypmod;
1161
1162                         attrname = pstrdup(n->colname);
1163                         if (n->typeName->setof)
1164                                 ereport(ERROR,
1165                                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
1166                                                  errmsg("column \"%s\" cannot be declared SETOF",
1167                                                                 attrname),
1168                                                  parser_errposition(pstate, n->typeName->location)));
1169                         attrtype = typenameTypeId(pstate, n->typeName, &attrtypmod);
1170                         eref->colnames = lappend(eref->colnames, makeString(attrname));
1171                         rte->funccoltypes = lappend_oid(rte->funccoltypes, attrtype);
1172                         rte->funccoltypmods = lappend_int(rte->funccoltypmods, attrtypmod);
1173                 }
1174         }
1175         else
1176                 ereport(ERROR,
1177                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1178                          errmsg("function \"%s\" in FROM has unsupported return type %s",
1179                                         funcname, format_type_be(funcrettype)),
1180                                  parser_errposition(pstate, exprLocation(funcexpr))));
1181
1182         /*----------
1183          * Flags:
1184          * - this RTE should be expanded to include descendant tables,
1185          * - this RTE is in the FROM clause,
1186          * - this RTE should be checked for appropriate access rights.
1187          *
1188          * Functions are never checked for access rights (at least, not by
1189          * the RTE permissions mechanism).
1190          *----------
1191          */
1192         rte->inh = false;                       /* never true for functions */
1193         rte->inFromCl = inFromCl;
1194
1195         rte->requiredPerms = 0;
1196         rte->checkAsUser = InvalidOid;
1197         rte->selectedCols = NULL;
1198         rte->modifiedCols = NULL;
1199
1200         /*
1201          * Add completed RTE to pstate's range table list, but not to join list
1202          * nor namespace --- caller must do that if appropriate.
1203          */
1204         if (pstate != NULL)
1205                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
1206
1207         return rte;
1208 }
1209
1210 /*
1211  * Add an entry for a VALUES list to the pstate's range table (p_rtable).
1212  *
1213  * This is much like addRangeTableEntry() except that it makes a values RTE.
1214  */
1215 RangeTblEntry *
1216 addRangeTableEntryForValues(ParseState *pstate,
1217                                                         List *exprs,
1218                                                         Alias *alias,
1219                                                         bool inFromCl)
1220 {
1221         RangeTblEntry *rte = makeNode(RangeTblEntry);
1222         char       *refname = alias ? alias->aliasname : pstrdup("*VALUES*");
1223         Alias      *eref;
1224         int                     numaliases;
1225         int                     numcolumns;
1226
1227         rte->rtekind = RTE_VALUES;
1228         rte->relid = InvalidOid;
1229         rte->subquery = NULL;
1230         rte->values_lists = exprs;
1231         rte->alias = alias;
1232
1233         eref = alias ? copyObject(alias) : makeAlias(refname, NIL);
1234
1235         /* fill in any unspecified alias columns */
1236         numcolumns = list_length((List *) linitial(exprs));
1237         numaliases = list_length(eref->colnames);
1238         while (numaliases < numcolumns)
1239         {
1240                 char            attrname[64];
1241
1242                 numaliases++;
1243                 snprintf(attrname, sizeof(attrname), "column%d", numaliases);
1244                 eref->colnames = lappend(eref->colnames,
1245                                                                  makeString(pstrdup(attrname)));
1246         }
1247         if (numcolumns < numaliases)
1248                 ereport(ERROR,
1249                                 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
1250                                  errmsg("VALUES lists \"%s\" have %d columns available but %d columns specified",
1251                                                 refname, numcolumns, numaliases)));
1252
1253         rte->eref = eref;
1254
1255         /*----------
1256          * Flags:
1257          * - this RTE should be expanded to include descendant tables,
1258          * - this RTE is in the FROM clause,
1259          * - this RTE should be checked for appropriate access rights.
1260          *
1261          * Subqueries are never checked for access rights.
1262          *----------
1263          */
1264         rte->inh = false;                       /* never true for values RTEs */
1265         rte->inFromCl = inFromCl;
1266
1267         rte->requiredPerms = 0;
1268         rte->checkAsUser = InvalidOid;
1269         rte->selectedCols = NULL;
1270         rte->modifiedCols = NULL;
1271
1272         /*
1273          * Add completed RTE to pstate's range table list, but not to join list
1274          * nor namespace --- caller must do that if appropriate.
1275          */
1276         if (pstate != NULL)
1277                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
1278
1279         return rte;
1280 }
1281
1282 /*
1283  * Add an entry for a join to the pstate's range table (p_rtable).
1284  *
1285  * This is much like addRangeTableEntry() except that it makes a join RTE.
1286  */
1287 RangeTblEntry *
1288 addRangeTableEntryForJoin(ParseState *pstate,
1289                                                   List *colnames,
1290                                                   JoinType jointype,
1291                                                   List *aliasvars,
1292                                                   Alias *alias,
1293                                                   bool inFromCl)
1294 {
1295         RangeTblEntry *rte = makeNode(RangeTblEntry);
1296         Alias      *eref;
1297         int                     numaliases;
1298
1299         /*
1300          * Fail if join has too many columns --- we must be able to reference any
1301          * of the columns with an AttrNumber.
1302          */
1303         if (list_length(aliasvars) > MaxAttrNumber)
1304                 ereport(ERROR,
1305                                 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
1306                                  errmsg("joins can have at most %d columns",
1307                                                 MaxAttrNumber)));
1308
1309         rte->rtekind = RTE_JOIN;
1310         rte->relid = InvalidOid;
1311         rte->subquery = NULL;
1312         rte->jointype = jointype;
1313         rte->joinaliasvars = aliasvars;
1314         rte->alias = alias;
1315
1316         eref = alias ? (Alias *) copyObject(alias) : makeAlias("unnamed_join", NIL);
1317         numaliases = list_length(eref->colnames);
1318
1319         /* fill in any unspecified alias columns */
1320         if (numaliases < list_length(colnames))
1321                 eref->colnames = list_concat(eref->colnames,
1322                                                                          list_copy_tail(colnames, numaliases));
1323
1324         rte->eref = eref;
1325
1326         /*----------
1327          * Flags:
1328          * - this RTE should be expanded to include descendant tables,
1329          * - this RTE is in the FROM clause,
1330          * - this RTE should be checked for appropriate access rights.
1331          *
1332          * Joins are never checked for access rights.
1333          *----------
1334          */
1335         rte->inh = false;                       /* never true for joins */
1336         rte->inFromCl = inFromCl;
1337
1338         rte->requiredPerms = 0;
1339         rte->checkAsUser = InvalidOid;
1340         rte->selectedCols = NULL;
1341         rte->modifiedCols = NULL;
1342
1343         /*
1344          * Add completed RTE to pstate's range table list, but not to join list
1345          * nor namespace --- caller must do that if appropriate.
1346          */
1347         if (pstate != NULL)
1348                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
1349
1350         return rte;
1351 }
1352
1353 /*
1354  * Add an entry for a CTE reference to the pstate's range table (p_rtable).
1355  *
1356  * This is much like addRangeTableEntry() except that it makes a CTE RTE.
1357  */
1358 RangeTblEntry *
1359 addRangeTableEntryForCTE(ParseState *pstate,
1360                                                  CommonTableExpr *cte,
1361                                                  Index levelsup,
1362                                                  Alias *alias,
1363                                                  bool inFromCl)
1364 {
1365         RangeTblEntry *rte = makeNode(RangeTblEntry);
1366         char       *refname = alias ? alias->aliasname : cte->ctename;
1367         Alias      *eref;
1368         int                     numaliases;
1369         int                     varattno;
1370         ListCell   *lc;
1371
1372         rte->rtekind = RTE_CTE;
1373         rte->ctename = cte->ctename;
1374         rte->ctelevelsup = levelsup;
1375
1376         /* Self-reference if and only if CTE's parse analysis isn't completed */
1377         rte->self_reference = !IsA(cte->ctequery, Query);
1378         Assert(cte->cterecursive || !rte->self_reference);
1379         /* Bump the CTE's refcount if this isn't a self-reference */
1380         if (!rte->self_reference)
1381                 cte->cterefcount++;
1382
1383         rte->ctecoltypes = cte->ctecoltypes;
1384         rte->ctecoltypmods = cte->ctecoltypmods;
1385
1386         rte->alias = alias;
1387         if (alias)
1388                 eref = copyObject(alias);
1389         else
1390                 eref = makeAlias(refname, NIL);
1391         numaliases = list_length(eref->colnames);
1392
1393         /* fill in any unspecified alias columns */
1394         varattno = 0;
1395         foreach(lc, cte->ctecolnames)
1396         {
1397                 varattno++;
1398                 if (varattno > numaliases)
1399                         eref->colnames = lappend(eref->colnames, lfirst(lc));
1400         }
1401         if (varattno < numaliases)
1402                 ereport(ERROR,
1403                                 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
1404                                  errmsg("table \"%s\" has %d columns available but %d columns specified",
1405                                                 refname, varattno, numaliases)));
1406
1407         rte->eref = eref;
1408
1409         /*----------
1410          * Flags:
1411          * - this RTE should be expanded to include descendant tables,
1412          * - this RTE is in the FROM clause,
1413          * - this RTE should be checked for appropriate access rights.
1414          *
1415          * Subqueries are never checked for access rights.
1416          *----------
1417          */
1418         rte->inh = false;                       /* never true for subqueries */
1419         rte->inFromCl = inFromCl;
1420
1421         rte->requiredPerms = 0;
1422         rte->checkAsUser = InvalidOid;
1423         rte->selectedCols = NULL;
1424         rte->modifiedCols = NULL;
1425
1426         /*
1427          * Add completed RTE to pstate's range table list, but not to join list
1428          * nor namespace --- caller must do that if appropriate.
1429          */
1430         if (pstate != NULL)
1431                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
1432
1433         return rte;
1434 }
1435
1436
1437 /*
1438  * Has the specified refname been selected FOR UPDATE/FOR SHARE?
1439  *
1440  * This is used when we have not yet done transformLockingClause, but need
1441  * to know the correct lock to take during initial opening of relations.
1442  *
1443  * Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE,
1444  * since the table-level lock is the same either way.
1445  */
1446 bool
1447 isLockedRefname(ParseState *pstate, const char *refname)
1448 {
1449         ListCell   *l;
1450
1451         /*
1452          * If we are in a subquery specified as locked FOR UPDATE/SHARE from
1453          * parent level, then act as though there's a generic FOR UPDATE here.
1454          */
1455         if (pstate->p_locked_from_parent)
1456                 return true;
1457
1458         foreach(l, pstate->p_locking_clause)
1459         {
1460                 LockingClause *lc = (LockingClause *) lfirst(l);
1461
1462                 if (lc->lockedRels == NIL)
1463                 {
1464                         /* all tables used in query */
1465                         return true;
1466                 }
1467                 else
1468                 {
1469                         /* just the named tables */
1470                         ListCell   *l2;
1471
1472                         foreach(l2, lc->lockedRels)
1473                         {
1474                                 RangeVar   *thisrel = (RangeVar *) lfirst(l2);
1475
1476                                 if (strcmp(refname, thisrel->relname) == 0)
1477                                         return true;
1478                         }
1479                 }
1480         }
1481         return false;
1482 }
1483
1484 /*
1485  * Add the given RTE as a top-level entry in the pstate's join list
1486  * and/or name space lists.  (We assume caller has checked for any
1487  * namespace conflicts.)
1488  */
1489 void
1490 addRTEtoQuery(ParseState *pstate, RangeTblEntry *rte,
1491                           bool addToJoinList,
1492                           bool addToRelNameSpace, bool addToVarNameSpace)
1493 {
1494         if (addToJoinList)
1495         {
1496                 int                     rtindex = RTERangeTablePosn(pstate, rte, NULL);
1497                 RangeTblRef *rtr = makeNode(RangeTblRef);
1498
1499                 rtr->rtindex = rtindex;
1500                 pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
1501         }
1502         if (addToRelNameSpace)
1503                 pstate->p_relnamespace = lappend(pstate->p_relnamespace, rte);
1504         if (addToVarNameSpace)
1505                 pstate->p_varnamespace = lappend(pstate->p_varnamespace, rte);
1506 }
1507
1508 /*
1509  * expandRTE -- expand the columns of a rangetable entry
1510  *
1511  * This creates lists of an RTE's column names (aliases if provided, else
1512  * real names) and Vars for each column.  Only user columns are considered.
1513  * If include_dropped is FALSE then dropped columns are omitted from the
1514  * results.  If include_dropped is TRUE then empty strings and NULL constants
1515  * (not Vars!) are returned for dropped columns.
1516  *
1517  * rtindex, sublevels_up, and location are the varno, varlevelsup, and location
1518  * values to use in the created Vars.  Ordinarily rtindex should match the
1519  * actual position of the RTE in its rangetable.
1520  *
1521  * The output lists go into *colnames and *colvars.
1522  * If only one of the two kinds of output list is needed, pass NULL for the
1523  * output pointer for the unwanted one.
1524  */
1525 void
1526 expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
1527                   int location, bool include_dropped,
1528                   List **colnames, List **colvars)
1529 {
1530         int                     varattno;
1531
1532         if (colnames)
1533                 *colnames = NIL;
1534         if (colvars)
1535                 *colvars = NIL;
1536
1537         switch (rte->rtekind)
1538         {
1539                 case RTE_RELATION:
1540                         /* Ordinary relation RTE */
1541                         expandRelation(rte->relid, rte->eref,
1542                                                    rtindex, sublevels_up, location,
1543                                                    include_dropped, colnames, colvars);
1544                         break;
1545                 case RTE_SUBQUERY:
1546                         {
1547                                 /* Subquery RTE */
1548                                 ListCell   *aliasp_item = list_head(rte->eref->colnames);
1549                                 ListCell   *tlistitem;
1550
1551                                 varattno = 0;
1552                                 foreach(tlistitem, rte->subquery->targetList)
1553                                 {
1554                                         TargetEntry *te = (TargetEntry *) lfirst(tlistitem);
1555
1556                                         if (te->resjunk)
1557                                                 continue;
1558                                         varattno++;
1559                                         Assert(varattno == te->resno);
1560
1561                                         if (colnames)
1562                                         {
1563                                                 /* Assume there is one alias per target item */
1564                                                 char       *label = strVal(lfirst(aliasp_item));
1565
1566                                                 *colnames = lappend(*colnames, makeString(pstrdup(label)));
1567                                                 aliasp_item = lnext(aliasp_item);
1568                                         }
1569
1570                                         if (colvars)
1571                                         {
1572                                                 Var                *varnode;
1573
1574                                                 varnode = makeVar(rtindex, varattno,
1575                                                                                   exprType((Node *) te->expr),
1576                                                                                   exprTypmod((Node *) te->expr),
1577                                                                                   sublevels_up);
1578                                                 varnode->location = location;
1579
1580                                                 *colvars = lappend(*colvars, varnode);
1581                                         }
1582                                 }
1583                         }
1584                         break;
1585                 case RTE_FUNCTION:
1586                         {
1587                                 /* Function RTE */
1588                                 TypeFuncClass functypclass;
1589                                 Oid                     funcrettype;
1590                                 TupleDesc       tupdesc;
1591
1592                                 functypclass = get_expr_result_type(rte->funcexpr,
1593                                                                                                         &funcrettype,
1594                                                                                                         &tupdesc);
1595                                 if (functypclass == TYPEFUNC_COMPOSITE)
1596                                 {
1597                                         /* Composite data type, e.g. a table's row type */
1598                                         Assert(tupdesc);
1599                                         expandTupleDesc(tupdesc, rte->eref,
1600                                                                         rtindex, sublevels_up, location,
1601                                                                         include_dropped, colnames, colvars);
1602                                 }
1603                                 else if (functypclass == TYPEFUNC_SCALAR)
1604                                 {
1605                                         /* Base data type, i.e. scalar */
1606                                         if (colnames)
1607                                                 *colnames = lappend(*colnames,
1608                                                                                         linitial(rte->eref->colnames));
1609
1610                                         if (colvars)
1611                                         {
1612                                                 Var                *varnode;
1613
1614                                                 varnode = makeVar(rtindex, 1,
1615                                                                                   funcrettype, -1,
1616                                                                                   sublevels_up);
1617                                                 varnode->location = location;
1618
1619                                                 *colvars = lappend(*colvars, varnode);
1620                                         }
1621                                 }
1622                                 else if (functypclass == TYPEFUNC_RECORD)
1623                                 {
1624                                         if (colnames)
1625                                                 *colnames = copyObject(rte->eref->colnames);
1626                                         if (colvars)
1627                                         {
1628                                                 ListCell   *l1;
1629                                                 ListCell   *l2;
1630                                                 int                     attnum = 0;
1631
1632                                                 forboth(l1, rte->funccoltypes, l2, rte->funccoltypmods)
1633                                                 {
1634                                                         Oid                     attrtype = lfirst_oid(l1);
1635                                                         int32           attrtypmod = lfirst_int(l2);
1636                                                         Var                *varnode;
1637
1638                                                         attnum++;
1639                                                         varnode = makeVar(rtindex,
1640                                                                                           attnum,
1641                                                                                           attrtype,
1642                                                                                           attrtypmod,
1643                                                                                           sublevels_up);
1644                                                         varnode->location = location;
1645                                                         *colvars = lappend(*colvars, varnode);
1646                                                 }
1647                                         }
1648                                 }
1649                                 else
1650                                 {
1651                                         /* addRangeTableEntryForFunction should've caught this */
1652                                         elog(ERROR, "function in FROM has unsupported return type");
1653                                 }
1654                         }
1655                         break;
1656                 case RTE_VALUES:
1657                         {
1658                                 /* Values RTE */
1659                                 ListCell   *aliasp_item = list_head(rte->eref->colnames);
1660                                 ListCell   *lc;
1661
1662                                 varattno = 0;
1663                                 foreach(lc, (List *) linitial(rte->values_lists))
1664                                 {
1665                                         Node       *col = (Node *) lfirst(lc);
1666
1667                                         varattno++;
1668                                         if (colnames)
1669                                         {
1670                                                 /* Assume there is one alias per column */
1671                                                 char       *label = strVal(lfirst(aliasp_item));
1672
1673                                                 *colnames = lappend(*colnames,
1674                                                                                         makeString(pstrdup(label)));
1675                                                 aliasp_item = lnext(aliasp_item);
1676                                         }
1677
1678                                         if (colvars)
1679                                         {
1680                                                 Var                *varnode;
1681
1682                                                 varnode = makeVar(rtindex, varattno,
1683                                                                                   exprType(col),
1684                                                                                   exprTypmod(col),
1685                                                                                   sublevels_up);
1686                                                 varnode->location = location;
1687                                                 *colvars = lappend(*colvars, varnode);
1688                                         }
1689                                 }
1690                         }
1691                         break;
1692                 case RTE_JOIN:
1693                         {
1694                                 /* Join RTE */
1695                                 ListCell   *colname;
1696                                 ListCell   *aliasvar;
1697
1698                                 Assert(list_length(rte->eref->colnames) == list_length(rte->joinaliasvars));
1699
1700                                 varattno = 0;
1701                                 forboth(colname, rte->eref->colnames, aliasvar, rte->joinaliasvars)
1702                                 {
1703                                         Node       *avar = (Node *) lfirst(aliasvar);
1704
1705                                         varattno++;
1706
1707                                         /*
1708                                          * During ordinary parsing, there will never be any
1709                                          * deleted columns in the join; but we have to check since
1710                                          * this routine is also used by the rewriter, and joins
1711                                          * found in stored rules might have join columns for
1712                                          * since-deleted columns.  This will be signaled by a NULL
1713                                          * Const in the alias-vars list.
1714                                          */
1715                                         if (IsA(avar, Const))
1716                                         {
1717                                                 if (include_dropped)
1718                                                 {
1719                                                         if (colnames)
1720                                                                 *colnames = lappend(*colnames,
1721                                                                                                         makeString(pstrdup("")));
1722                                                         if (colvars)
1723                                                                 *colvars = lappend(*colvars,
1724                                                                                                    copyObject(avar));
1725                                                 }
1726                                                 continue;
1727                                         }
1728
1729                                         if (colnames)
1730                                         {
1731                                                 char       *label = strVal(lfirst(colname));
1732
1733                                                 *colnames = lappend(*colnames,
1734                                                                                         makeString(pstrdup(label)));
1735                                         }
1736
1737                                         if (colvars)
1738                                         {
1739                                                 Var                *varnode;
1740
1741                                                 varnode = makeVar(rtindex, varattno,
1742                                                                                   exprType(avar),
1743                                                                                   exprTypmod(avar),
1744                                                                                   sublevels_up);
1745                                                 varnode->location = location;
1746
1747                                                 *colvars = lappend(*colvars, varnode);
1748                                         }
1749                                 }
1750                         }
1751                         break;
1752                 case RTE_CTE:
1753                         {
1754                                 ListCell   *aliasp_item = list_head(rte->eref->colnames);
1755                                 ListCell   *lct;
1756                                 ListCell   *lcm;
1757
1758                                 varattno = 0;
1759                                 forboth(lct, rte->ctecoltypes, lcm, rte->ctecoltypmods)
1760                                 {
1761                                         Oid                     coltype = lfirst_oid(lct);
1762                                         int32           coltypmod = lfirst_int(lcm);
1763
1764                                         varattno++;
1765
1766                                         if (colnames)
1767                                         {
1768                                                 /* Assume there is one alias per output column */
1769                                                 char       *label = strVal(lfirst(aliasp_item));
1770
1771                                                 *colnames = lappend(*colnames, makeString(pstrdup(label)));
1772                                                 aliasp_item = lnext(aliasp_item);
1773                                         }
1774
1775                                         if (colvars)
1776                                         {
1777                                                 Var                *varnode;
1778
1779                                                 varnode = makeVar(rtindex, varattno,
1780                                                                                   coltype, coltypmod,
1781                                                                                   sublevels_up);
1782                                                 *colvars = lappend(*colvars, varnode);
1783                                         }
1784                                 }
1785                         }
1786                         break;
1787                 default:
1788                         elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
1789         }
1790 }
1791
1792 /*
1793  * expandRelation -- expandRTE subroutine
1794  */
1795 static void
1796 expandRelation(Oid relid, Alias *eref, int rtindex, int sublevels_up,
1797                            int location, bool include_dropped,
1798                            List **colnames, List **colvars)
1799 {
1800         Relation        rel;
1801
1802         /* Get the tupledesc and turn it over to expandTupleDesc */
1803         rel = relation_open(relid, AccessShareLock);
1804         expandTupleDesc(rel->rd_att, eref, rtindex, sublevels_up,
1805                                         location, include_dropped,
1806                                         colnames, colvars);
1807         relation_close(rel, AccessShareLock);
1808 }
1809
1810 /*
1811  * expandTupleDesc -- expandRTE subroutine
1812  */
1813 static void
1814 expandTupleDesc(TupleDesc tupdesc, Alias *eref,
1815                                 int rtindex, int sublevels_up,
1816                                 int location, bool include_dropped,
1817                                 List **colnames, List **colvars)
1818 {
1819         int                     maxattrs = tupdesc->natts;
1820         int                     numaliases = list_length(eref->colnames);
1821         int                     varattno;
1822
1823         for (varattno = 0; varattno < maxattrs; varattno++)
1824         {
1825                 Form_pg_attribute attr = tupdesc->attrs[varattno];
1826
1827                 if (attr->attisdropped)
1828                 {
1829                         if (include_dropped)
1830                         {
1831                                 if (colnames)
1832                                         *colnames = lappend(*colnames, makeString(pstrdup("")));
1833                                 if (colvars)
1834                                 {
1835                                         /*
1836                                          * can't use atttypid here, but it doesn't really matter
1837                                          * what type the Const claims to be.
1838                                          */
1839                                         *colvars = lappend(*colvars, makeNullConst(INT4OID, -1));
1840                                 }
1841                         }
1842                         continue;
1843                 }
1844
1845                 if (colnames)
1846                 {
1847                         char       *label;
1848
1849                         if (varattno < numaliases)
1850                                 label = strVal(list_nth(eref->colnames, varattno));
1851                         else
1852                                 label = NameStr(attr->attname);
1853                         *colnames = lappend(*colnames, makeString(pstrdup(label)));
1854                 }
1855
1856                 if (colvars)
1857                 {
1858                         Var                *varnode;
1859
1860                         varnode = makeVar(rtindex, attr->attnum,
1861                                                           attr->atttypid, attr->atttypmod,
1862                                                           sublevels_up);
1863                         varnode->location = location;
1864
1865                         *colvars = lappend(*colvars, varnode);
1866                 }
1867         }
1868 }
1869
1870 /*
1871  * expandRelAttrs -
1872  *        Workhorse for "*" expansion: produce a list of targetentries
1873  *        for the attributes of the RTE
1874  *
1875  * As with expandRTE, rtindex/sublevels_up determine the varno/varlevelsup
1876  * fields of the Vars produced, and location sets their location.
1877  * pstate->p_next_resno determines the resnos assigned to the TLEs.
1878  * The referenced columns are marked as requiring SELECT access.
1879  */
1880 List *
1881 expandRelAttrs(ParseState *pstate, RangeTblEntry *rte,
1882                            int rtindex, int sublevels_up, int location)
1883 {
1884         List       *names,
1885                            *vars;
1886         ListCell   *name,
1887                            *var;
1888         List       *te_list = NIL;
1889
1890         expandRTE(rte, rtindex, sublevels_up, location, false,
1891                           &names, &vars);
1892
1893         /*
1894          * Require read access to the table.  This is normally redundant with the
1895          * markVarForSelectPriv calls below, but not if the table has zero
1896          * columns.
1897          */
1898         rte->requiredPerms |= ACL_SELECT;
1899
1900         forboth(name, names, var, vars)
1901         {
1902                 char       *label = strVal(lfirst(name));
1903                 Var                *varnode = (Var *) lfirst(var);
1904                 TargetEntry *te;
1905
1906                 te = makeTargetEntry((Expr *) varnode,
1907                                                          (AttrNumber) pstate->p_next_resno++,
1908                                                          label,
1909                                                          false);
1910                 te_list = lappend(te_list, te);
1911
1912                 /* Require read access to each column */
1913                 markVarForSelectPriv(pstate, varnode, rte);
1914         }
1915
1916         Assert(name == NULL && var == NULL);            /* lists not the same length? */
1917
1918         return te_list;
1919 }
1920
1921 /*
1922  * get_rte_attribute_name
1923  *              Get an attribute name from a RangeTblEntry
1924  *
1925  * This is unlike get_attname() because we use aliases if available.
1926  * In particular, it will work on an RTE for a subselect or join, whereas
1927  * get_attname() only works on real relations.
1928  *
1929  * "*" is returned if the given attnum is InvalidAttrNumber --- this case
1930  * occurs when a Var represents a whole tuple of a relation.
1931  */
1932 char *
1933 get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum)
1934 {
1935         if (attnum == InvalidAttrNumber)
1936                 return "*";
1937
1938         /*
1939          * If there is a user-written column alias, use it.
1940          */
1941         if (rte->alias &&
1942                 attnum > 0 && attnum <= list_length(rte->alias->colnames))
1943                 return strVal(list_nth(rte->alias->colnames, attnum - 1));
1944
1945         /*
1946          * If the RTE is a relation, go to the system catalogs not the
1947          * eref->colnames list.  This is a little slower but it will give the
1948          * right answer if the column has been renamed since the eref list was
1949          * built (which can easily happen for rules).
1950          */
1951         if (rte->rtekind == RTE_RELATION)
1952                 return get_relid_attribute_name(rte->relid, attnum);
1953
1954         /*
1955          * Otherwise use the column name from eref.  There should always be one.
1956          */
1957         if (attnum > 0 && attnum <= list_length(rte->eref->colnames))
1958                 return strVal(list_nth(rte->eref->colnames, attnum - 1));
1959
1960         /* else caller gave us a bogus attnum */
1961         elog(ERROR, "invalid attnum %d for rangetable entry %s",
1962                  attnum, rte->eref->aliasname);
1963         return NULL;                            /* keep compiler quiet */
1964 }
1965
1966 /*
1967  * get_rte_attribute_type
1968  *              Get attribute type information from a RangeTblEntry
1969  */
1970 void
1971 get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
1972                                            Oid *vartype, int32 *vartypmod)
1973 {
1974         switch (rte->rtekind)
1975         {
1976                 case RTE_RELATION:
1977                         {
1978                                 /* Plain relation RTE --- get the attribute's type info */
1979                                 HeapTuple       tp;
1980                                 Form_pg_attribute att_tup;
1981
1982                                 tp = SearchSysCache(ATTNUM,
1983                                                                         ObjectIdGetDatum(rte->relid),
1984                                                                         Int16GetDatum(attnum),
1985                                                                         0, 0);
1986                                 if (!HeapTupleIsValid(tp))              /* shouldn't happen */
1987                                         elog(ERROR, "cache lookup failed for attribute %d of relation %u",
1988                                                  attnum, rte->relid);
1989                                 att_tup = (Form_pg_attribute) GETSTRUCT(tp);
1990
1991                                 /*
1992                                  * If dropped column, pretend it ain't there.  See notes in
1993                                  * scanRTEForColumn.
1994                                  */
1995                                 if (att_tup->attisdropped)
1996                                         ereport(ERROR,
1997                                                         (errcode(ERRCODE_UNDEFINED_COLUMN),
1998                                         errmsg("column \"%s\" of relation \"%s\" does not exist",
1999                                                    NameStr(att_tup->attname),
2000                                                    get_rel_name(rte->relid))));
2001                                 *vartype = att_tup->atttypid;
2002                                 *vartypmod = att_tup->atttypmod;
2003                                 ReleaseSysCache(tp);
2004                         }
2005                         break;
2006                 case RTE_SUBQUERY:
2007                         {
2008                                 /* Subselect RTE --- get type info from subselect's tlist */
2009                                 TargetEntry *te = get_tle_by_resno(rte->subquery->targetList,
2010                                                                                                    attnum);
2011
2012                                 if (te == NULL || te->resjunk)
2013                                         elog(ERROR, "subquery %s does not have attribute %d",
2014                                                  rte->eref->aliasname, attnum);
2015                                 *vartype = exprType((Node *) te->expr);
2016                                 *vartypmod = exprTypmod((Node *) te->expr);
2017                         }
2018                         break;
2019                 case RTE_FUNCTION:
2020                         {
2021                                 /* Function RTE */
2022                                 TypeFuncClass functypclass;
2023                                 Oid                     funcrettype;
2024                                 TupleDesc       tupdesc;
2025
2026                                 functypclass = get_expr_result_type(rte->funcexpr,
2027                                                                                                         &funcrettype,
2028                                                                                                         &tupdesc);
2029
2030                                 if (functypclass == TYPEFUNC_COMPOSITE)
2031                                 {
2032                                         /* Composite data type, e.g. a table's row type */
2033                                         Form_pg_attribute att_tup;
2034
2035                                         Assert(tupdesc);
2036                                         /* this is probably a can't-happen case */
2037                                         if (attnum < 1 || attnum > tupdesc->natts)
2038                                                 ereport(ERROR,
2039                                                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
2040                                                 errmsg("column %d of relation \"%s\" does not exist",
2041                                                            attnum,
2042                                                            rte->eref->aliasname)));
2043
2044                                         att_tup = tupdesc->attrs[attnum - 1];
2045
2046                                         /*
2047                                          * If dropped column, pretend it ain't there.  See notes
2048                                          * in scanRTEForColumn.
2049                                          */
2050                                         if (att_tup->attisdropped)
2051                                                 ereport(ERROR,
2052                                                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
2053                                                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
2054                                                                                 NameStr(att_tup->attname),
2055                                                                                 rte->eref->aliasname)));
2056                                         *vartype = att_tup->atttypid;
2057                                         *vartypmod = att_tup->atttypmod;
2058                                 }
2059                                 else if (functypclass == TYPEFUNC_SCALAR)
2060                                 {
2061                                         /* Base data type, i.e. scalar */
2062                                         *vartype = funcrettype;
2063                                         *vartypmod = -1;
2064                                 }
2065                                 else if (functypclass == TYPEFUNC_RECORD)
2066                                 {
2067                                         *vartype = list_nth_oid(rte->funccoltypes, attnum - 1);
2068                                         *vartypmod = list_nth_int(rte->funccoltypmods, attnum - 1);
2069                                 }
2070                                 else
2071                                 {
2072                                         /* addRangeTableEntryForFunction should've caught this */
2073                                         elog(ERROR, "function in FROM has unsupported return type");
2074                                 }
2075                         }
2076                         break;
2077                 case RTE_VALUES:
2078                         {
2079                                 /* Values RTE --- get type info from first sublist */
2080                                 List       *collist = (List *) linitial(rte->values_lists);
2081                                 Node       *col;
2082
2083                                 if (attnum < 1 || attnum > list_length(collist))
2084                                         elog(ERROR, "values list %s does not have attribute %d",
2085                                                  rte->eref->aliasname, attnum);
2086                                 col = (Node *) list_nth(collist, attnum - 1);
2087                                 *vartype = exprType(col);
2088                                 *vartypmod = exprTypmod(col);
2089                         }
2090                         break;
2091                 case RTE_JOIN:
2092                         {
2093                                 /*
2094                                  * Join RTE --- get type info from join RTE's alias variable
2095                                  */
2096                                 Node       *aliasvar;
2097
2098                                 Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
2099                                 aliasvar = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
2100                                 *vartype = exprType(aliasvar);
2101                                 *vartypmod = exprTypmod(aliasvar);
2102                         }
2103                         break;
2104                 case RTE_CTE:
2105                         {
2106                                 /* CTE RTE --- get type info from lists in the RTE */
2107                                 Assert(attnum > 0 && attnum <= list_length(rte->ctecoltypes));
2108                                 *vartype = list_nth_oid(rte->ctecoltypes, attnum - 1);
2109                                 *vartypmod = list_nth_int(rte->ctecoltypmods, attnum - 1);
2110                         }
2111                         break;
2112                 default:
2113                         elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
2114         }
2115 }
2116
2117 /*
2118  * get_rte_attribute_is_dropped
2119  *              Check whether attempted attribute ref is to a dropped column
2120  */
2121 bool
2122 get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
2123 {
2124         bool            result;
2125
2126         switch (rte->rtekind)
2127         {
2128                 case RTE_RELATION:
2129                         {
2130                                 /*
2131                                  * Plain relation RTE --- get the attribute's catalog entry
2132                                  */
2133                                 HeapTuple       tp;
2134                                 Form_pg_attribute att_tup;
2135
2136                                 tp = SearchSysCache(ATTNUM,
2137                                                                         ObjectIdGetDatum(rte->relid),
2138                                                                         Int16GetDatum(attnum),
2139                                                                         0, 0);
2140                                 if (!HeapTupleIsValid(tp))              /* shouldn't happen */
2141                                         elog(ERROR, "cache lookup failed for attribute %d of relation %u",
2142                                                  attnum, rte->relid);
2143                                 att_tup = (Form_pg_attribute) GETSTRUCT(tp);
2144                                 result = att_tup->attisdropped;
2145                                 ReleaseSysCache(tp);
2146                         }
2147                         break;
2148                 case RTE_SUBQUERY:
2149                 case RTE_VALUES:
2150                 case RTE_CTE:
2151                         /* Subselect, Values, CTE RTEs never have dropped columns */
2152                         result = false;
2153                         break;
2154                 case RTE_JOIN:
2155                         {
2156                                 /*
2157                                  * A join RTE would not have dropped columns when constructed,
2158                                  * but one in a stored rule might contain columns that were
2159                                  * dropped from the underlying tables, if said columns are
2160                                  * nowhere explicitly referenced in the rule.  This will be
2161                                  * signaled to us by a NULL Const in the joinaliasvars list.
2162                                  */
2163                                 Var                *aliasvar;
2164
2165                                 if (attnum <= 0 ||
2166                                         attnum > list_length(rte->joinaliasvars))
2167                                         elog(ERROR, "invalid varattno %d", attnum);
2168                                 aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
2169
2170                                 result = IsA(aliasvar, Const);
2171                         }
2172                         break;
2173                 case RTE_FUNCTION:
2174                         {
2175                                 /* Function RTE */
2176                                 Oid                     funcrettype = exprType(rte->funcexpr);
2177                                 Oid                     funcrelid = typeidTypeRelid(funcrettype);
2178
2179                                 if (OidIsValid(funcrelid))
2180                                 {
2181                                         /*
2182                                          * Composite data type, i.e. a table's row type
2183                                          *
2184                                          * Same as ordinary relation RTE
2185                                          */
2186                                         HeapTuple       tp;
2187                                         Form_pg_attribute att_tup;
2188
2189                                         tp = SearchSysCache(ATTNUM,
2190                                                                                 ObjectIdGetDatum(funcrelid),
2191                                                                                 Int16GetDatum(attnum),
2192                                                                                 0, 0);
2193                                         if (!HeapTupleIsValid(tp))      /* shouldn't happen */
2194                                                 elog(ERROR, "cache lookup failed for attribute %d of relation %u",
2195                                                          attnum, funcrelid);
2196                                         att_tup = (Form_pg_attribute) GETSTRUCT(tp);
2197                                         result = att_tup->attisdropped;
2198                                         ReleaseSysCache(tp);
2199                                 }
2200                                 else
2201                                 {
2202                                         /*
2203                                          * Must be a base data type, i.e. scalar
2204                                          */
2205                                         result = false;
2206                                 }
2207                         }
2208                         break;
2209                 default:
2210                         elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
2211                         result = false;         /* keep compiler quiet */
2212         }
2213
2214         return result;
2215 }
2216
2217 /*
2218  * Given a targetlist and a resno, return the matching TargetEntry
2219  *
2220  * Returns NULL if resno is not present in list.
2221  *
2222  * Note: we need to search, rather than just indexing with list_nth(),
2223  * because not all tlists are sorted by resno.
2224  */
2225 TargetEntry *
2226 get_tle_by_resno(List *tlist, AttrNumber resno)
2227 {
2228         ListCell   *l;
2229
2230         foreach(l, tlist)
2231         {
2232                 TargetEntry *tle = (TargetEntry *) lfirst(l);
2233
2234                 if (tle->resno == resno)
2235                         return tle;
2236         }
2237         return NULL;
2238 }
2239
2240 /*
2241  * Given a Query and rangetable index, return relation's RowMarkClause if any
2242  *
2243  * Returns NULL if relation is not selected FOR UPDATE/SHARE
2244  */
2245 RowMarkClause *
2246 get_parse_rowmark(Query *qry, Index rtindex)
2247 {
2248         ListCell   *l;
2249
2250         foreach(l, qry->rowMarks)
2251         {
2252                 RowMarkClause *rc = (RowMarkClause *) lfirst(l);
2253
2254                 if (rc->rti == rtindex)
2255                         return rc;
2256         }
2257         return NULL;
2258 }
2259
2260 /*
2261  *      given relation and att name, return attnum of variable
2262  *
2263  *      Returns InvalidAttrNumber if the attr doesn't exist (or is dropped).
2264  *
2265  *      This should only be used if the relation is already
2266  *      heap_open()'ed.  Use the cache version get_attnum()
2267  *      for access to non-opened relations.
2268  */
2269 int
2270 attnameAttNum(Relation rd, const char *attname, bool sysColOK)
2271 {
2272         int                     i;
2273
2274         for (i = 0; i < rd->rd_rel->relnatts; i++)
2275         {
2276                 Form_pg_attribute att = rd->rd_att->attrs[i];
2277
2278                 if (namestrcmp(&(att->attname), attname) == 0 && !att->attisdropped)
2279                         return i + 1;
2280         }
2281
2282         if (sysColOK)
2283         {
2284                 if ((i = specialAttNum(attname)) != InvalidAttrNumber)
2285                 {
2286                         if (i != ObjectIdAttributeNumber || rd->rd_rel->relhasoids)
2287                                 return i;
2288                 }
2289         }
2290
2291         /* on failure */
2292         return InvalidAttrNumber;
2293 }
2294
2295 /* specialAttNum()
2296  *
2297  * Check attribute name to see if it is "special", e.g. "oid".
2298  * - thomas 2000-02-07
2299  *
2300  * Note: this only discovers whether the name could be a system attribute.
2301  * Caller needs to verify that it really is an attribute of the rel,
2302  * at least in the case of "oid", which is now optional.
2303  */
2304 static int
2305 specialAttNum(const char *attname)
2306 {
2307         Form_pg_attribute sysatt;
2308
2309         sysatt = SystemAttributeByName(attname,
2310                                                                    true /* "oid" will be accepted */ );
2311         if (sysatt != NULL)
2312                 return sysatt->attnum;
2313         return InvalidAttrNumber;
2314 }
2315
2316
2317 /*
2318  * given attribute id, return name of that attribute
2319  *
2320  *      This should only be used if the relation is already
2321  *      heap_open()'ed.  Use the cache version get_atttype()
2322  *      for access to non-opened relations.
2323  */
2324 Name
2325 attnumAttName(Relation rd, int attid)
2326 {
2327         if (attid <= 0)
2328         {
2329                 Form_pg_attribute sysatt;
2330
2331                 sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
2332                 return &sysatt->attname;
2333         }
2334         if (attid > rd->rd_att->natts)
2335                 elog(ERROR, "invalid attribute number %d", attid);
2336         return &rd->rd_att->attrs[attid - 1]->attname;
2337 }
2338
2339 /*
2340  * given attribute id, return type of that attribute
2341  *
2342  *      This should only be used if the relation is already
2343  *      heap_open()'ed.  Use the cache version get_atttype()
2344  *      for access to non-opened relations.
2345  */
2346 Oid
2347 attnumTypeId(Relation rd, int attid)
2348 {
2349         if (attid <= 0)
2350         {
2351                 Form_pg_attribute sysatt;
2352
2353                 sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
2354                 return sysatt->atttypid;
2355         }
2356         if (attid > rd->rd_att->natts)
2357                 elog(ERROR, "invalid attribute number %d", attid);
2358         return rd->rd_att->attrs[attid - 1]->atttypid;
2359 }
2360
2361 /*
2362  * Generate a suitable error about a missing RTE.
2363  *
2364  * Since this is a very common type of error, we work rather hard to
2365  * produce a helpful message.
2366  */
2367 void
2368 errorMissingRTE(ParseState *pstate, RangeVar *relation)
2369 {
2370         RangeTblEntry *rte;
2371         int                     sublevels_up;
2372         const char *badAlias = NULL;
2373
2374         /*
2375          * Check to see if there are any potential matches in the query's
2376          * rangetable.  (Note: cases involving a bad schema name in the
2377          * RangeVar will throw error immediately here.  That seems OK.)
2378          */
2379         rte = searchRangeTable(pstate, relation);
2380
2381         /*
2382          * If we found a match that has an alias and the alias is visible in the
2383          * namespace, then the problem is probably use of the relation's real name
2384          * instead of its alias, ie "SELECT foo.* FROM foo f". This mistake is
2385          * common enough to justify a specific hint.
2386          *
2387          * If we found a match that doesn't meet those criteria, assume the
2388          * problem is illegal use of a relation outside its scope, as in the
2389          * MySQL-ism "SELECT ... FROM a, b LEFT JOIN c ON (a.x = c.y)".
2390          */
2391         if (rte && rte->alias &&
2392                 strcmp(rte->eref->aliasname, relation->relname) != 0 &&
2393                 refnameRangeTblEntry(pstate, NULL, rte->eref->aliasname,
2394                                                          relation->location,
2395                                                          &sublevels_up) == rte)
2396                 badAlias = rte->eref->aliasname;
2397
2398         if (rte)
2399                 ereport(ERROR,
2400                                 (errcode(ERRCODE_UNDEFINED_TABLE),
2401                                  errmsg("invalid reference to FROM-clause entry for table \"%s\"",
2402                                                 relation->relname),
2403                                  (badAlias ?
2404                                   errhint("Perhaps you meant to reference the table alias \"%s\".",
2405                                                   badAlias) :
2406                                   errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
2407                                                   rte->eref->aliasname)),
2408                                  parser_errposition(pstate, relation->location)));
2409         else
2410                 ereport(ERROR,
2411                                 (errcode(ERRCODE_UNDEFINED_TABLE),
2412                                  errmsg("missing FROM-clause entry for table \"%s\"",
2413                                                 relation->relname),
2414                                  parser_errposition(pstate, relation->location)));
2415 }