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) 1996-2006, 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 1.123 2006/04/30 18:30:39 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include <ctype.h>
  18
  19 #include "access/heapam.h"
  20 #include "catalog/heap.h"
  21 #include "catalog/namespace.h"
  22 #include "catalog/pg_type.h"
  23 #include "funcapi.h"
  24 #include "nodes/makefuncs.h"
  25 #include "parser/parsetree.h"
  26 #include "parser/parse_expr.h"
  27 #include "parser/parse_relation.h"
  28 #include "parser/parse_type.h"
  29 #include "utils/builtins.h"
  30 #include "utils/lsyscache.h"
  31 #include "utils/syscache.h"
  32
  33
  34 /* GUC parameter */
  35 bool            add_missing_from;
  36
  37 static RangeTblEntry *scanNameSpaceForRefname(ParseState *pstate,
  38                                                 const char *refname);
  39 static RangeTblEntry *scanNameSpaceForRelid(ParseState *pstate, Oid relid);
  40 static bool isLockedRel(ParseState *pstate, char *refname);
  41 static void expandRelation(Oid relid, Alias *eref,
  42                            int rtindex, int sublevels_up,
  43                            bool include_dropped,
  44                            List **colnames, List **colvars);
  45 static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
  46                                 int rtindex, int sublevels_up,
  47                                 bool include_dropped,
  48                                 List **colnames, List **colvars);
  49 static int      specialAttNum(const char *attname);
  50 static void warnAutoRange(ParseState *pstate, RangeVar *relation,
  51                                                   int location);
  52
  53
  54 /*
  55  * refnameRangeTblEntry
  56  *        Given a possibly-qualified refname, look to see if it matches any RTE.
  57  *        If so, return a pointer to the RangeTblEntry; else return NULL.
  58  *
  59  *        Optionally get RTE's nesting depth (0 = current) into *sublevels_up.
  60  *        If sublevels_up is NULL, only consider items at the current nesting
  61  *        level.
  62  *
  63  * An unqualified refname (schemaname == NULL) can match any RTE with matching
  64  * alias, or matching unqualified relname in the case of alias-less relation
  65  * RTEs.  It is possible that such a refname matches multiple RTEs in the
  66  * nearest nesting level that has a match; if so, we report an error via
  67  * ereport().
  68  *
  69  * A qualified refname (schemaname != NULL) can only match a relation RTE
  70  * that (a) has no alias and (b) is for the same relation identified by
  71  * schemaname.refname.  In this case we convert schemaname.refname to a
  72  * relation OID and search by relid, rather than by alias name.  This is
  73  * peculiar, but it's what SQL92 says to do.
  74  */
  75 RangeTblEntry *
  76 refnameRangeTblEntry(ParseState *pstate,
  77                                          const char *schemaname,
  78                                          const char *refname,
  79                                          int *sublevels_up)
  80 {
  81         Oid                     relId = InvalidOid;
  82
  83         if (sublevels_up)
  84                 *sublevels_up = 0;
  85
  86         if (schemaname != NULL)
  87         {
  88                 Oid                     namespaceId;
  89
  90                 namespaceId = LookupExplicitNamespace(schemaname);
  91                 relId = get_relname_relid(refname, namespaceId);
  92                 if (!OidIsValid(relId))
  93                         return NULL;
  94         }
  95
  96         while (pstate != NULL)
  97         {
  98                 RangeTblEntry *result;
  99
 100                 if (OidIsValid(relId))
 101                         result = scanNameSpaceForRelid(pstate, relId);
 102                 else
 103                         result = scanNameSpaceForRefname(pstate, refname);
 104
 105                 if (result)
 106                         return result;
 107
 108                 if (sublevels_up)
 109                         (*sublevels_up)++;
 110                 else
 111                         break;
 112
 113                 pstate = pstate->parentParseState;
 114         }
 115         return NULL;
 116 }
 117
 118 /*
 119  * Search the query's table namespace for an RTE matching the
 120  * given unqualified refname.  Return the RTE if a unique match, or NULL
 121  * if no match.  Raise error if multiple matches.
 122  */
 123 static RangeTblEntry *
 124 scanNameSpaceForRefname(ParseState *pstate, const char *refname)
 125 {
 126         RangeTblEntry *result = NULL;
 127         ListCell   *l;
 128
 129         foreach(l, pstate->p_relnamespace)
 130         {
 131                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 132
 133                 if (strcmp(rte->eref->aliasname, refname) == 0)
 134                 {
 135                         if (result)
 136                                 ereport(ERROR,
 137                                                 (errcode(ERRCODE_AMBIGUOUS_ALIAS),
 138                                                  errmsg("table reference \"%s\" is ambiguous",
 139                                                                 refname)));
 140                         result = rte;
 141                 }
 142         }
 143         return result;
 144 }
 145
 146 /*
 147  * Search the query's table namespace for a relation RTE matching the
 148  * given relation OID.  Return the RTE if a unique match, or NULL
 149  * if no match.  Raise error if multiple matches (which shouldn't
 150  * happen if the namespace was checked correctly when it was created).
 151  *
 152  * See the comments for refnameRangeTblEntry to understand why this
 153  * acts the way it does.
 154  */
 155 static RangeTblEntry *
 156 scanNameSpaceForRelid(ParseState *pstate, Oid relid)
 157 {
 158         RangeTblEntry *result = NULL;
 159         ListCell   *l;
 160
 161         foreach(l, pstate->p_relnamespace)
 162         {
 163                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 164
 165                 /* yes, the test for alias == NULL should be there... */
 166                 if (rte->rtekind == RTE_RELATION &&
 167                         rte->relid == relid &&
 168                         rte->alias == NULL)
 169                 {
 170                         if (result)
 171                                 ereport(ERROR,
 172                                                 (errcode(ERRCODE_AMBIGUOUS_ALIAS),
 173                                                  errmsg("table reference %u is ambiguous",
 174                                                                 relid)));
 175                         result = rte;
 176                 }
 177         }
 178         return result;
 179 }
 180
 181 /*
 182  * searchRangeTable
 183  *        See if any RangeTblEntry could possibly match the RangeVar.
 184  *        If so, return a pointer to the RangeTblEntry; else return NULL.
 185  *
 186  * This is different from refnameRangeTblEntry in that it considers every
 187  * entry in the ParseState's rangetable(s), not only those that are currently
 188  * visible in the p_relnamespace lists.  This behavior is invalid per the SQL
 189  * spec, and it may give ambiguous results (there might be multiple equally
 190  * valid matches, but only one will be returned).  This must be used ONLY
 191  * as a heuristic in giving suitable error messages.  See warnAutoRange.
 192  *
 193  * Notice that we consider both matches on actual relation name and matches
 194  * on alias.
 195  */
 196 static RangeTblEntry *
 197 searchRangeTable(ParseState *pstate, RangeVar *relation)
 198 {
 199         Oid                     relId = RangeVarGetRelid(relation, true);
 200         char       *refname = relation->relname;
 201
 202         while (pstate != NULL)
 203         {
 204                 ListCell   *l;
 205
 206                 foreach(l, pstate->p_rtable)
 207                 {
 208                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 209
 210                         if (OidIsValid(relId) &&
 211                                 rte->rtekind == RTE_RELATION &&
 212                                 rte->relid == relId)
 213                                 return rte;
 214                         if (strcmp(rte->eref->aliasname, refname) == 0)
 215                                 return rte;
 216                 }
 217
 218                 pstate = pstate->parentParseState;
 219         }
 220         return NULL;
 221 }
 222
 223 /*
 224  * Check for relation-name conflicts between two relnamespace lists.
 225  * Raise an error if any is found.
 226  *
 227  * Note: we assume that each given argument does not contain conflicts
 228  * itself; we just want to know if the two can be merged together.
 229  *
 230  * Per SQL92, two alias-less plain relation RTEs do not conflict even if
 231  * they have the same eref->aliasname (ie, same relation name), if they
 232  * are for different relation OIDs (implying they are in different schemas).
 233  */
 234 void
 235 checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
 236                                                 List *namespace2)
 237 {
 238         ListCell   *l1;
 239
 240         foreach(l1, namespace1)
 241         {
 242                 RangeTblEntry *rte1 = (RangeTblEntry *) lfirst(l1);
 243                 const char *aliasname1 = rte1->eref->aliasname;
 244                 ListCell   *l2;
 245
 246                 foreach(l2, namespace2)
 247                 {
 248                         RangeTblEntry *rte2 = (RangeTblEntry *) lfirst(l2);
 249
 250                         if (strcmp(rte2->eref->aliasname, aliasname1) != 0)
 251                                 continue;               /* definitely no conflict */
 252                         if (rte1->rtekind == RTE_RELATION && rte1->alias == NULL &&
 253                                 rte2->rtekind == RTE_RELATION && rte2->alias == NULL &&
 254                                 rte1->relid != rte2->relid)
 255                                 continue;               /* no conflict per SQL92 rule */
 256                         ereport(ERROR,
 257                                         (errcode(ERRCODE_DUPLICATE_ALIAS),
 258                                          errmsg("table name \"%s\" specified more than once",
 259                                                         aliasname1)));
 260                 }
 261         }
 262 }
 263
 264 /*
 265  * given an RTE, return RT index (starting with 1) of the entry,
 266  * and optionally get its nesting depth (0 = current).  If sublevels_up
 267  * is NULL, only consider rels at the current nesting level.
 268  * Raises error if RTE not found.
 269  */
 270 int
 271 RTERangeTablePosn(ParseState *pstate, RangeTblEntry *rte, int *sublevels_up)
 272 {
 273         int                     index;
 274         ListCell   *l;
 275
 276         if (sublevels_up)
 277                 *sublevels_up = 0;
 278
 279         while (pstate != NULL)
 280         {
 281                 index = 1;
 282                 foreach(l, pstate->p_rtable)
 283                 {
 284                         if (rte == (RangeTblEntry *) lfirst(l))
 285                                 return index;
 286                         index++;
 287                 }
 288                 pstate = pstate->parentParseState;
 289                 if (sublevels_up)
 290                         (*sublevels_up)++;
 291                 else
 292                         break;
 293         }
 294
 295         elog(ERROR, "RTE not found (internal error)");
 296         return 0;                                       /* keep compiler quiet */
 297 }
 298
 299 /*
 300  * Given an RT index and nesting depth, find the corresponding RTE.
 301  * This is the inverse of RTERangeTablePosn.
 302  */
 303 RangeTblEntry *
 304 GetRTEByRangeTablePosn(ParseState *pstate,
 305                                            int varno,
 306                                            int sublevels_up)
 307 {
 308         while (sublevels_up-- > 0)
 309         {
 310                 pstate = pstate->parentParseState;
 311                 Assert(pstate != NULL);
 312         }
 313         Assert(varno > 0 && varno <= list_length(pstate->p_rtable));
 314         return rt_fetch(varno, pstate->p_rtable);
 315 }
 316
 317 /*
 318  * scanRTEForColumn
 319  *        Search the column names of a single RTE for the given name.
 320  *        If found, return an appropriate Var node, else return NULL.
 321  *        If the name proves ambiguous within this RTE, raise error.
 322  *
 323  * Side effect: if we find a match, mark the RTE as requiring read access.
 324  * See comments in setTargetTable().
 325  *
 326  * NOTE: if the RTE is for a join, marking it as requiring read access does
 327  * nothing.  It might seem that we need to propagate the mark to all the
 328  * contained RTEs, but that is not necessary.  This is so because a join
 329  * expression can only appear in a FROM clause, and any table named in
 330  * FROM will be marked as requiring read access from the beginning.
 331  */
 332 Node *
 333 scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte, char *colname,
 334                                  int location)
 335 {
 336         Node       *result = NULL;
 337         int                     attnum = 0;
 338         ListCell   *c;
 339
 340         /*
 341          * Scan the user column names (or aliases) for a match. Complain if
 342          * multiple matches.
 343          *
 344          * Note: eref->colnames may include entries for dropped columns, but those
 345          * will be empty strings that cannot match any legal SQL identifier, so we
 346          * don't bother to test for that case here.
 347          *
 348          * Should this somehow go wrong and we try to access a dropped column,
 349          * we'll still catch it by virtue of the checks in
 350          * get_rte_attribute_type(), which is called by make_var().  That routine
 351          * has to do a cache lookup anyway, so the check there is cheap.
 352          */
 353         foreach(c, rte->eref->colnames)
 354         {
 355                 attnum++;
 356                 if (strcmp(strVal(lfirst(c)), colname) == 0)
 357                 {
 358                         if (result)
 359                                 ereport(ERROR,
 360                                                 (errcode(ERRCODE_AMBIGUOUS_COLUMN),
 361                                                  errmsg("column reference \"%s\" is ambiguous",
 362                                                                 colname),
 363                                                  parser_errposition(pstate, location)));
 364                         result = (Node *) make_var(pstate, rte, attnum);
 365                         /* Require read access */
 366                         rte->requiredPerms |= ACL_SELECT;
 367                 }
 368         }
 369
 370         /*
 371          * If we have a unique match, return it.  Note that this allows a user
 372          * alias to override a system column name (such as OID) without error.
 373          */
 374         if (result)
 375                 return result;
 376
 377         /*
 378          * If the RTE represents a real table, consider system column names.
 379          */
 380         if (rte->rtekind == RTE_RELATION)
 381         {
 382                 /* quick check to see if name could be a system column */
 383                 attnum = specialAttNum(colname);
 384                 if (attnum != InvalidAttrNumber)
 385                 {
 386                         /* now check to see if column actually is defined */
 387                         if (SearchSysCacheExists(ATTNUM,
 388                                                                          ObjectIdGetDatum(rte->relid),
 389                                                                          Int16GetDatum(attnum),
 390                                                                          0, 0))
 391                         {
 392                                 result = (Node *) make_var(pstate, rte, attnum);
 393                                 /* Require read access */
 394                                 rte->requiredPerms |= ACL_SELECT;
 395                         }
 396                 }
 397         }
 398
 399         return result;
 400 }
 401
 402 /*
 403  * colNameToVar
 404  *        Search for an unqualified column name.
 405  *        If found, return the appropriate Var node (or expression).
 406  *        If not found, return NULL.  If the name proves ambiguous, raise error.
 407  *        If localonly is true, only names in the innermost query are considered.
 408  */
 409 Node *
 410 colNameToVar(ParseState *pstate, char *colname, bool localonly,
 411                          int location)
 412 {
 413         Node       *result = NULL;
 414         ParseState *orig_pstate = pstate;
 415
 416         while (pstate != NULL)
 417         {
 418                 ListCell   *l;
 419
 420                 foreach(l, pstate->p_varnamespace)
 421                 {
 422                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
 423                         Node       *newresult;
 424
 425                         /* use orig_pstate here to get the right sublevels_up */
 426                         newresult = scanRTEForColumn(orig_pstate, rte, colname, location);
 427
 428                         if (newresult)
 429                         {
 430                                 if (result)
 431                                         ereport(ERROR,
 432                                                         (errcode(ERRCODE_AMBIGUOUS_COLUMN),
 433                                                          errmsg("column reference \"%s\" is ambiguous",
 434                                                                         colname),
 435                                                          parser_errposition(orig_pstate, location)));
 436                                 result = newresult;
 437                         }
 438                 }
 439
 440                 if (result != NULL || localonly)
 441                         break;                          /* found, or don't want to look at parent */
 442
 443                 pstate = pstate->parentParseState;
 444         }
 445
 446         return result;
 447 }
 448
 449 /*
 450  * qualifiedNameToVar
 451  *        Search for a qualified column name: either refname.colname or
 452  *        schemaname.relname.colname.
 453  *
 454  *        If found, return the appropriate Var node.
 455  *        If not found, return NULL.  If the name proves ambiguous, raise error.
 456  */
 457 Node *
 458 qualifiedNameToVar(ParseState *pstate,
 459                                    char *schemaname,
 460                                    char *refname,
 461                                    char *colname,
 462                                    bool implicitRTEOK,
 463                                    int location)
 464 {
 465         RangeTblEntry *rte;
 466         int                     sublevels_up;
 467
 468         rte = refnameRangeTblEntry(pstate, schemaname, refname, &sublevels_up);
 469
 470         if (rte == NULL)
 471         {
 472                 if (!implicitRTEOK)
 473                         return NULL;
 474                 rte = addImplicitRTE(pstate, makeRangeVar(schemaname, refname),
 475                                                          location);
 476         }
 477
 478         return scanRTEForColumn(pstate, rte, colname, location);
 479 }
 480
 481 /*
 482  * buildRelationAliases
 483  *              Construct the eref column name list for a relation RTE.
 484  *              This code is also used for the case of a function RTE returning
 485  *              a named composite type.
 486  *
 487  * tupdesc: the physical column information
 488  * alias: the user-supplied alias, or NULL if none
 489  * eref: the eref Alias to store column names in
 490  *
 491  * eref->colnames is filled in.  Also, alias->colnames is rebuilt to insert
 492  * empty strings for any dropped columns, so that it will be one-to-one with
 493  * physical column numbers.
 494  */
 495 static void
 496 buildRelationAliases(TupleDesc tupdesc, Alias *alias, Alias *eref)
 497 {
 498         int                     maxattrs = tupdesc->natts;
 499         ListCell   *aliaslc;
 500         int                     numaliases;
 501         int                     varattno;
 502         int                     numdropped = 0;
 503
 504         Assert(eref->colnames == NIL);
 505
 506         if (alias)
 507         {
 508                 aliaslc = list_head(alias->colnames);
 509                 numaliases = list_length(alias->colnames);
 510                 /* We'll rebuild the alias colname list */
 511                 alias->colnames = NIL;
 512         }
 513         else
 514         {
 515                 aliaslc = NULL;
 516                 numaliases = 0;
 517         }
 518
 519         for (varattno = 0; varattno < maxattrs; varattno++)
 520         {
 521                 Form_pg_attribute attr = tupdesc->attrs[varattno];
 522                 Value      *attrname;
 523
 524                 if (attr->attisdropped)
 525                 {
 526                         /* Always insert an empty string for a dropped column */
 527                         attrname = makeString(pstrdup(""));
 528                         if (aliaslc)
 529                                 alias->colnames = lappend(alias->colnames, attrname);
 530                         numdropped++;
 531                 }
 532                 else if (aliaslc)
 533                 {
 534                         /* Use the next user-supplied alias */
 535                         attrname = (Value *) lfirst(aliaslc);
 536                         aliaslc = lnext(aliaslc);
 537                         alias->colnames = lappend(alias->colnames, attrname);
 538                 }
 539                 else
 540                 {
 541                         attrname = makeString(pstrdup(NameStr(attr->attname)));
 542                         /* we're done with the alias if any */
 543                 }
 544
 545                 eref->colnames = lappend(eref->colnames, attrname);
 546         }
 547
 548         /* Too many user-supplied aliases? */
 549         if (aliaslc)
 550                 ereport(ERROR,
 551                                 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
 552                                  errmsg("table \"%s\" has %d columns available but %d columns specified",
 553                                                 eref->aliasname, maxattrs - numdropped, numaliases)));
 554 }
 555
 556 /*
 557  * buildScalarFunctionAlias
 558  *              Construct the eref column name list for a function RTE,
 559  *              when the function returns a scalar type (not composite or RECORD).
 560  *
 561  * funcexpr: transformed expression tree for the function call
 562  * funcname: function name (used only for error message)
 563  * alias: the user-supplied alias, or NULL if none
 564  * eref: the eref Alias to store column names in
 565  *
 566  * eref->colnames is filled in.
 567  */
 568 static void
 569 buildScalarFunctionAlias(Node *funcexpr, char *funcname,
 570                                                  Alias *alias, Alias *eref)
 571 {
 572         char       *pname;
 573
 574         Assert(eref->colnames == NIL);
 575
 576         /* Use user-specified column alias if there is one. */
 577         if (alias && alias->colnames != NIL)
 578         {
 579                 if (list_length(alias->colnames) != 1)
 580                         ereport(ERROR,
 581                                         (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
 582                                   errmsg("too many column aliases specified for function %s",
 583                                                  funcname)));
 584                 eref->colnames = copyObject(alias->colnames);
 585                 return;
 586         }
 587
 588         /*
 589          * If the expression is a simple function call, and the function has a
 590          * single OUT parameter that is named, use the parameter's name.
 591          */
 592         if (funcexpr && IsA(funcexpr, FuncExpr))
 593         {
 594                 pname = get_func_result_name(((FuncExpr *) funcexpr)->funcid);
 595                 if (pname)
 596                 {
 597                         eref->colnames = list_make1(makeString(pname));
 598                         return;
 599                 }
 600         }
 601
 602         /*
 603          * Otherwise use the previously-determined alias (not necessarily the
 604          * function name!)
 605          */
 606         eref->colnames = list_make1(makeString(eref->aliasname));
 607 }
 608
 609 /*
 610  * Add an entry for a relation to the pstate's range table (p_rtable).
 611  *
 612  * If pstate is NULL, we just build an RTE and return it without adding it
 613  * to an rtable list.
 614  *
 615  * Note: formerly this checked for refname conflicts, but that's wrong.
 616  * Caller is responsible for checking for conflicts in the appropriate scope.
 617  */
 618 RangeTblEntry *
 619 addRangeTableEntry(ParseState *pstate,
 620                                    RangeVar *relation,
 621                                    Alias *alias,
 622                                    bool inh,
 623                                    bool inFromCl)
 624 {
 625         RangeTblEntry *rte = makeNode(RangeTblEntry);
 626         char       *refname = alias ? alias->aliasname : relation->relname;
 627         LOCKMODE        lockmode;
 628         Relation        rel;
 629
 630         rte->rtekind = RTE_RELATION;
 631         rte->alias = alias;
 632
 633         /*
 634          * Get the rel's OID.  This access also ensures that we have an up-to-date
 635          * relcache entry for the rel.  Since this is typically the first access
 636          * to a rel in a statement, be careful to get the right access level
 637          * depending on whether we're doing SELECT FOR UPDATE/SHARE.
 638          */
 639         lockmode = isLockedRel(pstate, refname) ? RowShareLock : AccessShareLock;
 640         rel = heap_openrv(relation, lockmode);
 641         rte->relid = RelationGetRelid(rel);
 642
 643         /*
 644          * Build the list of effective column names using user-supplied aliases
 645          * and/or actual column names.
 646          */
 647         rte->eref = makeAlias(refname, NIL);
 648         buildRelationAliases(rel->rd_att, alias, rte->eref);
 649
 650         /*
 651          * Drop the rel refcount, but keep the access lock till end of transaction
 652          * so that the table can't be deleted or have its schema modified
 653          * underneath us.
 654          */
 655         heap_close(rel, NoLock);
 656
 657         /*----------
 658          * Flags:
 659          * - this RTE should be expanded to include descendant tables,
 660          * - this RTE is in the FROM clause,
 661          * - this RTE should be checked for appropriate access rights.
 662          *
 663          * The initial default on access checks is always check-for-READ-access,
 664          * which is the right thing for all except target tables.
 665          *----------
 666          */
 667         rte->inh = inh;
 668         rte->inFromCl = inFromCl;
 669
 670         rte->requiredPerms = ACL_SELECT;
 671         rte->checkAsUser = InvalidOid;          /* not set-uid by default, either */
 672
 673         /*
 674          * Add completed RTE to pstate's range table list, but not to join list
 675          * nor namespace --- caller must do that if appropriate.
 676          */
 677         if (pstate != NULL)
 678                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
 679
 680         return rte;
 681 }
 682
 683 /*
 684  * Add an entry for a relation to the pstate's range table (p_rtable).
 685  *
 686  * This is just like addRangeTableEntry() except that it makes an RTE
 687  * given an already-open relation instead of a RangeVar reference.
 688  */
 689 RangeTblEntry *
 690 addRangeTableEntryForRelation(ParseState *pstate,
 691                                                           Relation rel,
 692                                                           Alias *alias,
 693                                                           bool inh,
 694                                                           bool inFromCl)
 695 {
 696         RangeTblEntry *rte = makeNode(RangeTblEntry);
 697         char       *refname = alias ? alias->aliasname : RelationGetRelationName(rel);
 698
 699         rte->rtekind = RTE_RELATION;
 700         rte->alias = alias;
 701         rte->relid = RelationGetRelid(rel);
 702
 703         /*
 704          * Build the list of effective column names using user-supplied aliases
 705          * and/or actual column names.
 706          */
 707         rte->eref = makeAlias(refname, NIL);
 708         buildRelationAliases(rel->rd_att, alias, rte->eref);
 709
 710         /*----------
 711          * Flags:
 712          * - this RTE should be expanded to include descendant tables,
 713          * - this RTE is in the FROM clause,
 714          * - this RTE should be checked for appropriate access rights.
 715          *
 716          * The initial default on access checks is always check-for-READ-access,
 717          * which is the right thing for all except target tables.
 718          *----------
 719          */
 720         rte->inh = inh;
 721         rte->inFromCl = inFromCl;
 722
 723         rte->requiredPerms = ACL_SELECT;
 724         rte->checkAsUser = InvalidOid;          /* not set-uid by default, either */
 725
 726         /*
 727          * Add completed RTE to pstate's range table list, but not to join list
 728          * nor namespace --- caller must do that if appropriate.
 729          */
 730         if (pstate != NULL)
 731                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
 732
 733         return rte;
 734 }
 735
 736 /*
 737  * Add an entry for a subquery to the pstate's range table (p_rtable).
 738  *
 739  * This is just like addRangeTableEntry() except that it makes a subquery RTE.
 740  * Note that an alias clause *must* be supplied.
 741  */
 742 RangeTblEntry *
 743 addRangeTableEntryForSubquery(ParseState *pstate,
 744                                                           Query *subquery,
 745                                                           Alias *alias,
 746                                                           bool inFromCl)
 747 {
 748         RangeTblEntry *rte = makeNode(RangeTblEntry);
 749         char       *refname = alias->aliasname;
 750         Alias      *eref;
 751         int                     numaliases;
 752         int                     varattno;
 753         ListCell   *tlistitem;
 754
 755         rte->rtekind = RTE_SUBQUERY;
 756         rte->relid = InvalidOid;
 757         rte->subquery = subquery;
 758         rte->alias = alias;
 759
 760         eref = copyObject(alias);
 761         numaliases = list_length(eref->colnames);
 762
 763         /* fill in any unspecified alias columns */
 764         varattno = 0;
 765         foreach(tlistitem, subquery->targetList)
 766         {
 767                 TargetEntry *te = (TargetEntry *) lfirst(tlistitem);
 768
 769                 if (te->resjunk)
 770                         continue;
 771                 varattno++;
 772                 Assert(varattno == te->resno);
 773                 if (varattno > numaliases)
 774                 {
 775                         char       *attrname;
 776
 777                         attrname = pstrdup(te->resname);
 778                         eref->colnames = lappend(eref->colnames, makeString(attrname));
 779                 }
 780         }
 781         if (varattno < numaliases)
 782                 ereport(ERROR,
 783                                 (errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
 784                                  errmsg("table \"%s\" has %d columns available but %d columns specified",
 785                                                 refname, varattno, numaliases)));
 786
 787         rte->eref = eref;
 788
 789         /*----------
 790          * Flags:
 791          * - this RTE should be expanded to include descendant tables,
 792          * - this RTE is in the FROM clause,
 793          * - this RTE should be checked for appropriate access rights.
 794          *
 795          * Subqueries are never checked for access rights.
 796          *----------
 797          */
 798         rte->inh = false;                       /* never true for subqueries */
 799         rte->inFromCl = inFromCl;
 800
 801         rte->requiredPerms = 0;
 802         rte->checkAsUser = InvalidOid;
 803
 804         /*
 805          * Add completed RTE to pstate's range table list, but not to join list
 806          * nor namespace --- caller must do that if appropriate.
 807          */
 808         if (pstate != NULL)
 809                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
 810
 811         return rte;
 812 }
 813
 814 /*
 815  * Add an entry for a function to the pstate's range table (p_rtable).
 816  *
 817  * This is just like addRangeTableEntry() except that it makes a function RTE.
 818  */
 819 RangeTblEntry *
 820 addRangeTableEntryForFunction(ParseState *pstate,
 821                                                           char *funcname,
 822                                                           Node *funcexpr,
 823                                                           RangeFunction *rangefunc,
 824                                                           bool inFromCl)
 825 {
 826         RangeTblEntry *rte = makeNode(RangeTblEntry);
 827         TypeFuncClass functypclass;
 828         Oid                     funcrettype;
 829         TupleDesc       tupdesc;
 830         Alias      *alias = rangefunc->alias;
 831         List       *coldeflist = rangefunc->coldeflist;
 832         Alias      *eref;
 833
 834         rte->rtekind = RTE_FUNCTION;
 835         rte->relid = InvalidOid;
 836         rte->subquery = NULL;
 837         rte->funcexpr = funcexpr;
 838         rte->funccoltypes = NIL;
 839         rte->funccoltypmods = NIL;
 840         rte->alias = alias;
 841
 842         eref = makeAlias(alias ? alias->aliasname : funcname, NIL);
 843         rte->eref = eref;
 844
 845         /*
 846          * Now determine if the function returns a simple or composite type.
 847          */
 848         functypclass = get_expr_result_type(funcexpr,
 849                                                                                 &funcrettype,
 850                                                                                 &tupdesc);
 851
 852         /*
 853          * A coldeflist is required if the function returns RECORD and hasn't got
 854          * a predetermined record type, and is prohibited otherwise.
 855          */
 856         if (coldeflist != NIL)
 857         {
 858                 if (functypclass != TYPEFUNC_RECORD)
 859                         ereport(ERROR,
 860                                         (errcode(ERRCODE_SYNTAX_ERROR),
 861                                          errmsg("a column definition list is only allowed for functions returning \"record\"")));
 862         }
 863         else
 864         {
 865                 if (functypclass == TYPEFUNC_RECORD)
 866                         ereport(ERROR,
 867                                         (errcode(ERRCODE_SYNTAX_ERROR),
 868                                          errmsg("a column definition list is required for functions returning \"record\"")));
 869         }
 870
 871         if (functypclass == TYPEFUNC_COMPOSITE)
 872         {
 873                 /* Composite data type, e.g. a table's row type */
 874                 Assert(tupdesc);
 875                 /* Build the column alias list */
 876                 buildRelationAliases(tupdesc, alias, eref);
 877         }
 878         else if (functypclass == TYPEFUNC_SCALAR)
 879         {
 880                 /* Base data type, i.e. scalar */
 881                 buildScalarFunctionAlias(funcexpr, funcname, alias, eref);
 882         }
 883         else if (functypclass == TYPEFUNC_RECORD)
 884         {
 885                 ListCell   *col;
 886
 887                 /*
 888                  * Use the column definition list to form the alias list and
 889                  * funccoltypes/funccoltypmods lists.
 890                  */
 891                 foreach(col, coldeflist)
 892                 {
 893                         ColumnDef  *n = (ColumnDef *) lfirst(col);
 894                         char       *attrname;
 895                         Oid                     attrtype;
 896                         int32           attrtypmod;
 897
 898                         attrname = pstrdup(n->colname);
 899                         if (n->typename->setof)
 900                                 ereport(ERROR,
 901                                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 902                                                  errmsg("column \"%s\" cannot be declared SETOF",
 903                                                                 attrname)));
 904                         eref->colnames = lappend(eref->colnames, makeString(attrname));
 905                         attrtype = typenameTypeId(pstate, n->typename);
 906                         attrtypmod = n->typename->typmod;
 907                         rte->funccoltypes = lappend_oid(rte->funccoltypes, attrtype);
 908                         rte->funccoltypmods = lappend_int(rte->funccoltypmods, attrtypmod);
 909                 }
 910         }
 911         else
 912                 ereport(ERROR,
 913                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
 914                          errmsg("function \"%s\" in FROM has unsupported return type %s",
 915                                         funcname, format_type_be(funcrettype))));
 916
 917         /*----------
 918          * Flags:
 919          * - this RTE should be expanded to include descendant tables,
 920          * - this RTE is in the FROM clause,
 921          * - this RTE should be checked for appropriate access rights.
 922          *
 923          * Functions are never checked for access rights (at least, not by
 924          * the RTE permissions mechanism).
 925          *----------
 926          */
 927         rte->inh = false;                       /* never true for functions */
 928         rte->inFromCl = inFromCl;
 929
 930         rte->requiredPerms = 0;
 931         rte->checkAsUser = InvalidOid;
 932
 933         /*
 934          * Add completed RTE to pstate's range table list, but not to join list
 935          * nor namespace --- caller must do that if appropriate.
 936          */
 937         if (pstate != NULL)
 938                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
 939
 940         return rte;
 941 }
 942
 943 /*
 944  * Add an entry for a join to the pstate's range table (p_rtable).
 945  *
 946  * This is much like addRangeTableEntry() except that it makes a join RTE.
 947  */
 948 RangeTblEntry *
 949 addRangeTableEntryForJoin(ParseState *pstate,
 950                                                   List *colnames,
 951                                                   JoinType jointype,
 952                                                   List *aliasvars,
 953                                                   Alias *alias,
 954                                                   bool inFromCl)
 955 {
 956         RangeTblEntry *rte = makeNode(RangeTblEntry);
 957         Alias      *eref;
 958         int                     numaliases;
 959
 960         rte->rtekind = RTE_JOIN;
 961         rte->relid = InvalidOid;
 962         rte->subquery = NULL;
 963         rte->jointype = jointype;
 964         rte->joinaliasvars = aliasvars;
 965         rte->alias = alias;
 966
 967         eref = alias ? (Alias *) copyObject(alias) : makeAlias("unnamed_join", NIL);
 968         numaliases = list_length(eref->colnames);
 969
 970         /* fill in any unspecified alias columns */
 971         if (numaliases < list_length(colnames))
 972                 eref->colnames = list_concat(eref->colnames,
 973                                                                          list_copy_tail(colnames, numaliases));
 974
 975         rte->eref = eref;
 976
 977         /*----------
 978          * Flags:
 979          * - this RTE should be expanded to include descendant tables,
 980          * - this RTE is in the FROM clause,
 981          * - this RTE should be checked for appropriate access rights.
 982          *
 983          * Joins are never checked for access rights.
 984          *----------
 985          */
 986         rte->inh = false;                       /* never true for joins */
 987         rte->inFromCl = inFromCl;
 988
 989         rte->requiredPerms = 0;
 990         rte->checkAsUser = InvalidOid;
 991
 992         /*
 993          * Add completed RTE to pstate's range table list, but not to join list
 994          * nor namespace --- caller must do that if appropriate.
 995          */
 996         if (pstate != NULL)
 997                 pstate->p_rtable = lappend(pstate->p_rtable, rte);
 998
 999         return rte;
1000 }
1001
1002 /*
1003  * Has the specified refname been selected FOR UPDATE/FOR SHARE?
1004  *
1005  * Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE.
1006  */
1007 static bool
1008 isLockedRel(ParseState *pstate, char *refname)
1009 {
1010         /* Outer loop to check parent query levels as well as this one */
1011         while (pstate != NULL)
1012         {
1013                 ListCell   *l;
1014
1015                 foreach(l, pstate->p_locking_clause)
1016                 {
1017                         LockingClause *lc = (LockingClause *) lfirst(l);
1018
1019                         if (lc->lockedRels == NIL)
1020                         {
1021                                 /* all tables used in query */
1022                                 return true;
1023                         }
1024                         else
1025                         {
1026                                 /* just the named tables */
1027                                 ListCell   *l2;
1028
1029                                 foreach(l2, lc->lockedRels)
1030                                 {
1031                                         char       *rname = strVal(lfirst(l2));
1032
1033                                         if (strcmp(refname, rname) == 0)
1034                                                 return true;
1035                                 }
1036                         }
1037                 }
1038                 pstate = pstate->parentParseState;
1039         }
1040         return false;
1041 }
1042
1043 /*
1044  * Add the given RTE as a top-level entry in the pstate's join list
1045  * and/or name space lists.  (We assume caller has checked for any
1046  * namespace conflicts.)
1047  */
1048 void
1049 addRTEtoQuery(ParseState *pstate, RangeTblEntry *rte,
1050                           bool addToJoinList,
1051                           bool addToRelNameSpace, bool addToVarNameSpace)
1052 {
1053         if (addToJoinList)
1054         {
1055                 int                     rtindex = RTERangeTablePosn(pstate, rte, NULL);
1056                 RangeTblRef *rtr = makeNode(RangeTblRef);
1057
1058                 rtr->rtindex = rtindex;
1059                 pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
1060         }
1061         if (addToRelNameSpace)
1062                 pstate->p_relnamespace = lappend(pstate->p_relnamespace, rte);
1063         if (addToVarNameSpace)
1064                 pstate->p_varnamespace = lappend(pstate->p_varnamespace, rte);
1065 }
1066
1067 /*
1068  * Add a POSTQUEL-style implicit RTE.
1069  *
1070  * We assume caller has already checked that there is no RTE or join with
1071  * a conflicting name.
1072  */
1073 RangeTblEntry *
1074 addImplicitRTE(ParseState *pstate, RangeVar *relation, int location)
1075 {
1076         RangeTblEntry *rte;
1077
1078         /* issue warning or error as needed */
1079         warnAutoRange(pstate, relation, location);
1080         /*
1081          * Note that we set inFromCl true, so that the RTE will be listed
1082          * explicitly if the parsetree is ever decompiled by ruleutils.c. This
1083          * provides a migration path for views/rules that were originally written
1084          * with implicit-RTE syntax.
1085          */
1086         rte = addRangeTableEntry(pstate, relation, NULL, false, true);
1087         /* Add to joinlist and relnamespace, but not varnamespace */
1088         addRTEtoQuery(pstate, rte, true, true, false);
1089
1090         return rte;
1091 }
1092
1093 /*
1094  * expandRTE -- expand the columns of a rangetable entry
1095  *
1096  * This creates lists of an RTE's column names (aliases if provided, else
1097  * real names) and Vars for each column.  Only user columns are considered.
1098  * If include_dropped is FALSE then dropped columns are omitted from the
1099  * results.  If include_dropped is TRUE then empty strings and NULL constants
1100  * (not Vars!) are returned for dropped columns.
1101  *
1102  * rtindex and sublevels_up are the varno and varlevelsup values to use
1103  * in the created Vars.  Ordinarily rtindex should match the actual position
1104  * of the RTE in its rangetable.
1105  *
1106  * The output lists go into *colnames and *colvars.
1107  * If only one of the two kinds of output list is needed, pass NULL for the
1108  * output pointer for the unwanted one.
1109  */
1110 void
1111 expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
1112                   bool include_dropped,
1113                   List **colnames, List **colvars)
1114 {
1115         int                     varattno;
1116
1117         if (colnames)
1118                 *colnames = NIL;
1119         if (colvars)
1120                 *colvars = NIL;
1121
1122         switch (rte->rtekind)
1123         {
1124                 case RTE_RELATION:
1125                         /* Ordinary relation RTE */
1126                         expandRelation(rte->relid, rte->eref, rtindex, sublevels_up,
1127                                                    include_dropped, colnames, colvars);
1128                         break;
1129                 case RTE_SUBQUERY:
1130                         {
1131                                 /* Subquery RTE */
1132                                 ListCell   *aliasp_item = list_head(rte->eref->colnames);
1133                                 ListCell   *tlistitem;
1134
1135                                 varattno = 0;
1136                                 foreach(tlistitem, rte->subquery->targetList)
1137                                 {
1138                                         TargetEntry *te = (TargetEntry *) lfirst(tlistitem);
1139
1140                                         if (te->resjunk)
1141                                                 continue;
1142                                         varattno++;
1143                                         Assert(varattno == te->resno);
1144
1145                                         if (colnames)
1146                                         {
1147                                                 /* Assume there is one alias per target item */
1148                                                 char       *label = strVal(lfirst(aliasp_item));
1149
1150                                                 *colnames = lappend(*colnames, makeString(pstrdup(label)));
1151                                                 aliasp_item = lnext(aliasp_item);
1152                                         }
1153
1154                                         if (colvars)
1155                                         {
1156                                                 Var                *varnode;
1157
1158                                                 varnode = makeVar(rtindex, varattno,
1159                                                                                   exprType((Node *) te->expr),
1160                                                                                   exprTypmod((Node *) te->expr),
1161                                                                                   sublevels_up);
1162
1163                                                 *colvars = lappend(*colvars, varnode);
1164                                         }
1165                                 }
1166                         }
1167                         break;
1168                 case RTE_FUNCTION:
1169                         {
1170                                 /* Function RTE */
1171                                 TypeFuncClass functypclass;
1172                                 Oid                     funcrettype;
1173                                 TupleDesc       tupdesc;
1174
1175                                 functypclass = get_expr_result_type(rte->funcexpr,
1176                                                                                                         &funcrettype,
1177                                                                                                         &tupdesc);
1178                                 if (functypclass == TYPEFUNC_COMPOSITE)
1179                                 {
1180                                         /* Composite data type, e.g. a table's row type */
1181                                         Assert(tupdesc);
1182                                         expandTupleDesc(tupdesc, rte->eref, rtindex, sublevels_up,
1183                                                                         include_dropped, colnames, colvars);
1184                                 }
1185                                 else if (functypclass == TYPEFUNC_SCALAR)
1186                                 {
1187                                         /* Base data type, i.e. scalar */
1188                                         if (colnames)
1189                                                 *colnames = lappend(*colnames,
1190                                                                                         linitial(rte->eref->colnames));
1191
1192                                         if (colvars)
1193                                         {
1194                                                 Var                *varnode;
1195
1196                                                 varnode = makeVar(rtindex, 1,
1197                                                                                   funcrettype, -1,
1198                                                                                   sublevels_up);
1199
1200                                                 *colvars = lappend(*colvars, varnode);
1201                                         }
1202                                 }
1203                                 else if (functypclass == TYPEFUNC_RECORD)
1204                                 {
1205                                         if (colnames)
1206                                                 *colnames = copyObject(rte->eref->colnames);
1207                                         if (colvars)
1208                                         {
1209                                                 ListCell   *l1;
1210                                                 ListCell   *l2;
1211                                                 int                     attnum = 0;
1212
1213                                                 forboth(l1, rte->funccoltypes, l2, rte->funccoltypmods)
1214                                                 {
1215                                                         Oid                     attrtype = lfirst_oid(l1);
1216                                                         int32           attrtypmod = lfirst_int(l2);
1217                                                         Var                *varnode;
1218
1219                                                         attnum++;
1220                                                         varnode = makeVar(rtindex,
1221                                                                                           attnum,
1222                                                                                           attrtype,
1223                                                                                           attrtypmod,
1224                                                                                           sublevels_up);
1225                                                         *colvars = lappend(*colvars, varnode);
1226                                                 }
1227                                         }
1228                                 }
1229                                 else
1230                                 {
1231                                         /* addRangeTableEntryForFunction should've caught this */
1232                                         elog(ERROR, "function in FROM has unsupported return type");
1233                                 }
1234                         }
1235                         break;
1236                 case RTE_JOIN:
1237                         {
1238                                 /* Join RTE */
1239                                 ListCell   *colname;
1240                                 ListCell   *aliasvar;
1241
1242                                 Assert(list_length(rte->eref->colnames) == list_length(rte->joinaliasvars));
1243
1244                                 varattno = 0;
1245                                 forboth(colname, rte->eref->colnames, aliasvar, rte->joinaliasvars)
1246                                 {
1247                                         Node       *avar = (Node *) lfirst(aliasvar);
1248
1249                                         varattno++;
1250
1251                                         /*
1252                                          * During ordinary parsing, there will never be any
1253                                          * deleted columns in the join; but we have to check since
1254                                          * this routine is also used by the rewriter, and joins
1255                                          * found in stored rules might have join columns for
1256                                          * since-deleted columns.  This will be signaled by a NULL
1257                                          * Const in the alias-vars list.
1258                                          */
1259                                         if (IsA(avar, Const))
1260                                         {
1261                                                 if (include_dropped)
1262                                                 {
1263                                                         if (colnames)
1264                                                                 *colnames = lappend(*colnames,
1265                                                                                                         makeString(pstrdup("")));
1266                                                         if (colvars)
1267                                                                 *colvars = lappend(*colvars,
1268                                                                                                    copyObject(avar));
1269                                                 }
1270                                                 continue;
1271                                         }
1272
1273                                         if (colnames)
1274                                         {
1275                                                 char       *label = strVal(lfirst(colname));
1276
1277                                                 *colnames = lappend(*colnames,
1278                                                                                         makeString(pstrdup(label)));
1279                                         }
1280
1281                                         if (colvars)
1282                                         {
1283                                                 Var                *varnode;
1284
1285                                                 varnode = makeVar(rtindex, varattno,
1286                                                                                   exprType(avar),
1287                                                                                   exprTypmod(avar),
1288                                                                                   sublevels_up);
1289
1290                                                 *colvars = lappend(*colvars, varnode);
1291                                         }
1292                                 }
1293                         }
1294                         break;
1295                 default:
1296                         elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
1297         }
1298 }
1299
1300 /*
1301  * expandRelation -- expandRTE subroutine
1302  */
1303 static void
1304 expandRelation(Oid relid, Alias *eref, int rtindex, int sublevels_up,
1305                            bool include_dropped,
1306                            List **colnames, List **colvars)
1307 {
1308         Relation        rel;
1309
1310         /* Get the tupledesc and turn it over to expandTupleDesc */
1311         rel = relation_open(relid, AccessShareLock);
1312         expandTupleDesc(rel->rd_att, eref, rtindex, sublevels_up, include_dropped,
1313                                         colnames, colvars);
1314         relation_close(rel, AccessShareLock);
1315 }
1316
1317 /*
1318  * expandTupleDesc -- expandRTE subroutine
1319  */
1320 static void
1321 expandTupleDesc(TupleDesc tupdesc, Alias *eref,
1322                                 int rtindex, int sublevels_up,
1323                                 bool include_dropped,
1324                                 List **colnames, List **colvars)
1325 {
1326         int                     maxattrs = tupdesc->natts;
1327         int                     numaliases = list_length(eref->colnames);
1328         int                     varattno;
1329
1330         for (varattno = 0; varattno < maxattrs; varattno++)
1331         {
1332                 Form_pg_attribute attr = tupdesc->attrs[varattno];
1333
1334                 if (attr->attisdropped)
1335                 {
1336                         if (include_dropped)
1337                         {
1338                                 if (colnames)
1339                                         *colnames = lappend(*colnames, makeString(pstrdup("")));
1340                                 if (colvars)
1341                                 {
1342                                         /*
1343                                          * can't use atttypid here, but it doesn't really matter
1344                                          * what type the Const claims to be.
1345                                          */
1346                                         *colvars = lappend(*colvars, makeNullConst(INT4OID));
1347                                 }
1348                         }
1349                         continue;
1350                 }
1351
1352                 if (colnames)
1353                 {
1354                         char       *label;
1355
1356                         if (varattno < numaliases)
1357                                 label = strVal(list_nth(eref->colnames, varattno));
1358                         else
1359                                 label = NameStr(attr->attname);
1360                         *colnames = lappend(*colnames, makeString(pstrdup(label)));
1361                 }
1362
1363                 if (colvars)
1364                 {
1365                         Var                *varnode;
1366
1367                         varnode = makeVar(rtindex, attr->attnum,
1368                                                           attr->atttypid, attr->atttypmod,
1369                                                           sublevels_up);
1370
1371                         *colvars = lappend(*colvars, varnode);
1372                 }
1373         }
1374 }
1375
1376 /*
1377  * expandRelAttrs -
1378  *        Workhorse for "*" expansion: produce a list of targetentries
1379  *        for the attributes of the rte
1380  *
1381  * As with expandRTE, rtindex/sublevels_up determine the varno/varlevelsup
1382  * fields of the Vars produced.  pstate->p_next_resno determines the resnos
1383  * assigned to the TLEs.
1384  */
1385 List *
1386 expandRelAttrs(ParseState *pstate, RangeTblEntry *rte,
1387                            int rtindex, int sublevels_up)
1388 {
1389         List       *names,
1390                            *vars;
1391         ListCell   *name,
1392                            *var;
1393         List       *te_list = NIL;
1394
1395         expandRTE(rte, rtindex, sublevels_up, false,
1396                           &names, &vars);
1397
1398         forboth(name, names, var, vars)
1399         {
1400                 char       *label = strVal(lfirst(name));
1401                 Node       *varnode = (Node *) lfirst(var);
1402                 TargetEntry *te;
1403
1404                 te = makeTargetEntry((Expr *) varnode,
1405                                                          (AttrNumber) pstate->p_next_resno++,
1406                                                          label,
1407                                                          false);
1408                 te_list = lappend(te_list, te);
1409         }
1410
1411         Assert(name == NULL && var == NULL);            /* lists not the same length? */
1412
1413         return te_list;
1414 }
1415
1416 /*
1417  * get_rte_attribute_name
1418  *              Get an attribute name from a RangeTblEntry
1419  *
1420  * This is unlike get_attname() because we use aliases if available.
1421  * In particular, it will work on an RTE for a subselect or join, whereas
1422  * get_attname() only works on real relations.
1423  *
1424  * "*" is returned if the given attnum is InvalidAttrNumber --- this case
1425  * occurs when a Var represents a whole tuple of a relation.
1426  */
1427 char *
1428 get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum)
1429 {
1430         if (attnum == InvalidAttrNumber)
1431                 return "*";
1432
1433         /*
1434          * If there is a user-written column alias, use it.
1435          */
1436         if (rte->alias &&
1437                 attnum > 0 && attnum <= list_length(rte->alias->colnames))
1438                 return strVal(list_nth(rte->alias->colnames, attnum - 1));
1439
1440         /*
1441          * If the RTE is a relation, go to the system catalogs not the
1442          * eref->colnames list.  This is a little slower but it will give the
1443          * right answer if the column has been renamed since the eref list was
1444          * built (which can easily happen for rules).
1445          */
1446         if (rte->rtekind == RTE_RELATION)
1447                 return get_relid_attribute_name(rte->relid, attnum);
1448
1449         /*
1450          * Otherwise use the column name from eref.  There should always be one.
1451          */
1452         if (attnum > 0 && attnum <= list_length(rte->eref->colnames))
1453                 return strVal(list_nth(rte->eref->colnames, attnum - 1));
1454
1455         /* else caller gave us a bogus attnum */
1456         elog(ERROR, "invalid attnum %d for rangetable entry %s",
1457                  attnum, rte->eref->aliasname);
1458         return NULL;                            /* keep compiler quiet */
1459 }
1460
1461 /*
1462  * get_rte_attribute_type
1463  *              Get attribute type information from a RangeTblEntry
1464  */
1465 void
1466 get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
1467                                            Oid *vartype, int32 *vartypmod)
1468 {
1469         switch (rte->rtekind)
1470         {
1471                 case RTE_RELATION:
1472                         {
1473                                 /* Plain relation RTE --- get the attribute's type info */
1474                                 HeapTuple       tp;
1475                                 Form_pg_attribute att_tup;
1476
1477                                 tp = SearchSysCache(ATTNUM,
1478                                                                         ObjectIdGetDatum(rte->relid),
1479                                                                         Int16GetDatum(attnum),
1480                                                                         0, 0);
1481                                 if (!HeapTupleIsValid(tp))              /* shouldn't happen */
1482                                         elog(ERROR, "cache lookup failed for attribute %d of relation %u",
1483                                                  attnum, rte->relid);
1484                                 att_tup = (Form_pg_attribute) GETSTRUCT(tp);
1485
1486                                 /*
1487                                  * If dropped column, pretend it ain't there.  See notes in
1488                                  * scanRTEForColumn.
1489                                  */
1490                                 if (att_tup->attisdropped)
1491                                         ereport(ERROR,
1492                                                         (errcode(ERRCODE_UNDEFINED_COLUMN),
1493                                         errmsg("column \"%s\" of relation \"%s\" does not exist",
1494                                                    NameStr(att_tup->attname),
1495                                                    get_rel_name(rte->relid))));
1496                                 *vartype = att_tup->atttypid;
1497                                 *vartypmod = att_tup->atttypmod;
1498                                 ReleaseSysCache(tp);
1499                         }
1500                         break;
1501                 case RTE_SUBQUERY:
1502                         {
1503                                 /* Subselect RTE --- get type info from subselect's tlist */
1504                                 TargetEntry *te = get_tle_by_resno(rte->subquery->targetList,
1505                                                                                                    attnum);
1506
1507                                 if (te == NULL || te->resjunk)
1508                                         elog(ERROR, "subquery %s does not have attribute %d",
1509                                                  rte->eref->aliasname, attnum);
1510                                 *vartype = exprType((Node *) te->expr);
1511                                 *vartypmod = exprTypmod((Node *) te->expr);
1512                         }
1513                         break;
1514                 case RTE_FUNCTION:
1515                         {
1516                                 /* Function RTE */
1517                                 TypeFuncClass functypclass;
1518                                 Oid                     funcrettype;
1519                                 TupleDesc       tupdesc;
1520
1521                                 functypclass = get_expr_result_type(rte->funcexpr,
1522                                                                                                         &funcrettype,
1523                                                                                                         &tupdesc);
1524
1525                                 if (functypclass == TYPEFUNC_COMPOSITE)
1526                                 {
1527                                         /* Composite data type, e.g. a table's row type */
1528                                         Form_pg_attribute att_tup;
1529
1530                                         Assert(tupdesc);
1531                                         /* this is probably a can't-happen case */
1532                                         if (attnum < 1 || attnum > tupdesc->natts)
1533                                                 ereport(ERROR,
1534                                                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
1535                                                 errmsg("column %d of relation \"%s\" does not exist",
1536                                                            attnum,
1537                                                            rte->eref->aliasname)));
1538
1539                                         att_tup = tupdesc->attrs[attnum - 1];
1540
1541                                         /*
1542                                          * If dropped column, pretend it ain't there.  See notes
1543                                          * in scanRTEForColumn.
1544                                          */
1545                                         if (att_tup->attisdropped)
1546                                                 ereport(ERROR,
1547                                                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
1548                                                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
1549                                                                                 NameStr(att_tup->attname),
1550                                                                                 rte->eref->aliasname)));
1551                                         *vartype = att_tup->atttypid;
1552                                         *vartypmod = att_tup->atttypmod;
1553                                 }
1554                                 else if (functypclass == TYPEFUNC_SCALAR)
1555                                 {
1556                                         /* Base data type, i.e. scalar */
1557                                         *vartype = funcrettype;
1558                                         *vartypmod = -1;
1559                                 }
1560                                 else if (functypclass == TYPEFUNC_RECORD)
1561                                 {
1562                                         *vartype = list_nth_oid(rte->funccoltypes, attnum - 1);
1563                                         *vartypmod = list_nth_int(rte->funccoltypmods, attnum - 1);
1564                                 }
1565                                 else
1566                                 {
1567                                         /* addRangeTableEntryForFunction should've caught this */
1568                                         elog(ERROR, "function in FROM has unsupported return type");
1569                                 }
1570                         }
1571                         break;
1572                 case RTE_JOIN:
1573                         {
1574                                 /*
1575                                  * Join RTE --- get type info from join RTE's alias variable
1576                                  */
1577                                 Node       *aliasvar;
1578
1579                                 Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
1580                                 aliasvar = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
1581                                 *vartype = exprType(aliasvar);
1582                                 *vartypmod = exprTypmod(aliasvar);
1583                         }
1584                         break;
1585                 default:
1586                         elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
1587         }
1588 }
1589
1590 /*
1591  * get_rte_attribute_is_dropped
1592  *              Check whether attempted attribute ref is to a dropped column
1593  */
1594 bool
1595 get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
1596 {
1597         bool            result;
1598
1599         switch (rte->rtekind)
1600         {
1601                 case RTE_RELATION:
1602                         {
1603                                 /*
1604                                  * Plain relation RTE --- get the attribute's catalog entry
1605                                  */
1606                                 HeapTuple       tp;
1607                                 Form_pg_attribute att_tup;
1608
1609                                 tp = SearchSysCache(ATTNUM,
1610                                                                         ObjectIdGetDatum(rte->relid),
1611                                                                         Int16GetDatum(attnum),
1612                                                                         0, 0);
1613                                 if (!HeapTupleIsValid(tp))              /* shouldn't happen */
1614                                         elog(ERROR, "cache lookup failed for attribute %d of relation %u",
1615                                                  attnum, rte->relid);
1616                                 att_tup = (Form_pg_attribute) GETSTRUCT(tp);
1617                                 result = att_tup->attisdropped;
1618                                 ReleaseSysCache(tp);
1619                         }
1620                         break;
1621                 case RTE_SUBQUERY:
1622                         /* Subselect RTEs never have dropped columns */
1623                         result = false;
1624                         break;
1625                 case RTE_JOIN:
1626                         {
1627                                 /*
1628                                  * A join RTE would not have dropped columns when constructed,
1629                                  * but one in a stored rule might contain columns that were
1630                                  * dropped from the underlying tables, if said columns are
1631                                  * nowhere explicitly referenced in the rule.  This will be
1632                                  * signaled to us by a NULL Const in the joinaliasvars list.
1633                                  */
1634                                 Var                *aliasvar;
1635
1636                                 if (attnum <= 0 ||
1637                                         attnum > list_length(rte->joinaliasvars))
1638                                         elog(ERROR, "invalid varattno %d", attnum);
1639                                 aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
1640
1641                                 result = IsA(aliasvar, Const);
1642                         }
1643                         break;
1644                 case RTE_FUNCTION:
1645                         {
1646                                 /* Function RTE */
1647                                 Oid                     funcrettype = exprType(rte->funcexpr);
1648                                 Oid                     funcrelid = typeidTypeRelid(funcrettype);
1649
1650                                 if (OidIsValid(funcrelid))
1651                                 {
1652                                         /*
1653                                          * Composite data type, i.e. a table's row type
1654                                          *
1655                                          * Same as ordinary relation RTE
1656                                          */
1657                                         HeapTuple       tp;
1658                                         Form_pg_attribute att_tup;
1659
1660                                         tp = SearchSysCache(ATTNUM,
1661                                                                                 ObjectIdGetDatum(funcrelid),
1662                                                                                 Int16GetDatum(attnum),
1663                                                                                 0, 0);
1664                                         if (!HeapTupleIsValid(tp))      /* shouldn't happen */
1665                                                 elog(ERROR, "cache lookup failed for attribute %d of relation %u",
1666                                                          attnum, funcrelid);
1667                                         att_tup = (Form_pg_attribute) GETSTRUCT(tp);
1668                                         result = att_tup->attisdropped;
1669                                         ReleaseSysCache(tp);
1670                                 }
1671                                 else
1672                                 {
1673                                         /*
1674                                          * Must be a base data type, i.e. scalar
1675                                          */
1676                                         result = false;
1677                                 }
1678                         }
1679                         break;
1680                 default:
1681                         elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
1682                         result = false;         /* keep compiler quiet */
1683         }
1684
1685         return result;
1686 }
1687
1688 /*
1689  * Given a targetlist and a resno, return the matching TargetEntry
1690  *
1691  * Returns NULL if resno is not present in list.
1692  *
1693  * Note: we need to search, rather than just indexing with list_nth(),
1694  * because not all tlists are sorted by resno.
1695  */
1696 TargetEntry *
1697 get_tle_by_resno(List *tlist, AttrNumber resno)
1698 {
1699         ListCell   *l;
1700
1701         foreach(l, tlist)
1702         {
1703                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1704
1705                 if (tle->resno == resno)
1706                         return tle;
1707         }
1708         return NULL;
1709 }
1710
1711 /*
1712  * Given a Query and rangetable index, return relation's RowMarkClause if any
1713  *
1714  * Returns NULL if relation is not selected FOR UPDATE/SHARE
1715  */
1716 RowMarkClause *
1717 get_rowmark(Query *qry, Index rtindex)
1718 {
1719         ListCell   *l;
1720
1721         foreach(l, qry->rowMarks)
1722         {
1723                 RowMarkClause *rc = (RowMarkClause *) lfirst(l);
1724
1725                 if (rc->rti == rtindex)
1726                         return rc;
1727         }
1728         return NULL;
1729 }
1730
1731 /*
1732  *      given relation and att name, return attnum of variable
1733  *
1734  *      Returns InvalidAttrNumber if the attr doesn't exist (or is dropped).
1735  *
1736  *      This should only be used if the relation is already
1737  *      heap_open()'ed.  Use the cache version get_attnum()
1738  *      for access to non-opened relations.
1739  */
1740 int
1741 attnameAttNum(Relation rd, const char *attname, bool sysColOK)
1742 {
1743         int                     i;
1744
1745         for (i = 0; i < rd->rd_rel->relnatts; i++)
1746         {
1747                 Form_pg_attribute att = rd->rd_att->attrs[i];
1748
1749                 if (namestrcmp(&(att->attname), attname) == 0 && !att->attisdropped)
1750                         return i + 1;
1751         }
1752
1753         if (sysColOK)
1754         {
1755                 if ((i = specialAttNum(attname)) != InvalidAttrNumber)
1756                 {
1757                         if (i != ObjectIdAttributeNumber || rd->rd_rel->relhasoids)
1758                                 return i;
1759                 }
1760         }
1761
1762         /* on failure */
1763         return InvalidAttrNumber;
1764 }
1765
1766 /* specialAttNum()
1767  *
1768  * Check attribute name to see if it is "special", e.g. "oid".
1769  * - thomas 2000-02-07
1770  *
1771  * Note: this only discovers whether the name could be a system attribute.
1772  * Caller needs to verify that it really is an attribute of the rel,
1773  * at least in the case of "oid", which is now optional.
1774  */
1775 static int
1776 specialAttNum(const char *attname)
1777 {
1778         Form_pg_attribute sysatt;
1779
1780         sysatt = SystemAttributeByName(attname,
1781                                                                    true /* "oid" will be accepted */ );
1782         if (sysatt != NULL)
1783                 return sysatt->attnum;
1784         return InvalidAttrNumber;
1785 }
1786
1787
1788 /*
1789  * given attribute id, return name of that attribute
1790  *
1791  *      This should only be used if the relation is already
1792  *      heap_open()'ed.  Use the cache version get_atttype()
1793  *      for access to non-opened relations.
1794  */
1795 Name
1796 attnumAttName(Relation rd, int attid)
1797 {
1798         if (attid <= 0)
1799         {
1800                 Form_pg_attribute sysatt;
1801
1802                 sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
1803                 return &sysatt->attname;
1804         }
1805         if (attid > rd->rd_att->natts)
1806                 elog(ERROR, "invalid attribute number %d", attid);
1807         return &rd->rd_att->attrs[attid - 1]->attname;
1808 }
1809
1810 /*
1811  * given attribute id, return type of that attribute
1812  *
1813  *      This should only be used if the relation is already
1814  *      heap_open()'ed.  Use the cache version get_atttype()
1815  *      for access to non-opened relations.
1816  */
1817 Oid
1818 attnumTypeId(Relation rd, int attid)
1819 {
1820         if (attid <= 0)
1821         {
1822                 Form_pg_attribute sysatt;
1823
1824                 sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
1825                 return sysatt->atttypid;
1826         }
1827         if (attid > rd->rd_att->natts)
1828                 elog(ERROR, "invalid attribute number %d", attid);
1829         return rd->rd_att->attrs[attid - 1]->atttypid;
1830 }
1831
1832 /*
1833  * Generate a warning or error about an implicit RTE, if appropriate.
1834  *
1835  * If ADD_MISSING_FROM is not enabled, raise an error. Otherwise, emit
1836  * a warning.
1837  */
1838 static void
1839 warnAutoRange(ParseState *pstate, RangeVar *relation, int location)
1840 {
1841         RangeTblEntry *rte;
1842         int                     sublevels_up;
1843         const char *badAlias = NULL;
1844
1845         /*
1846          * Check to see if there are any potential matches in the query's
1847          * rangetable.  This affects the message we provide.
1848          */
1849         rte = searchRangeTable(pstate, relation);
1850
1851         /*
1852          * If we found a match that has an alias and the alias is visible in
1853          * the namespace, then the problem is probably use of the relation's
1854          * real name instead of its alias, ie "SELECT foo.* FROM foo f".
1855          * This mistake is common enough to justify a specific hint.
1856          *
1857          * If we found a match that doesn't meet those criteria, assume the
1858          * problem is illegal use of a relation outside its scope, as in the
1859          * MySQL-ism "SELECT ... FROM a, b LEFT JOIN c ON (a.x = c.y)".
1860          */
1861         if (rte && rte->alias &&
1862                 strcmp(rte->eref->aliasname, relation->relname) != 0 &&
1863                 refnameRangeTblEntry(pstate, NULL, rte->eref->aliasname,
1864                                                          &sublevels_up) == rte)
1865                 badAlias = rte->eref->aliasname;
1866
1867         if (!add_missing_from)
1868         {
1869                 if (rte)
1870                         ereport(ERROR,
1871                                         (errcode(ERRCODE_UNDEFINED_TABLE),
1872                                          errmsg("invalid reference to FROM-clause entry for table \"%s\"",
1873                                                         relation->relname),
1874                                          (badAlias ?
1875                                           errhint("Perhaps you meant to reference the table alias \"%s\".",
1876                                                           badAlias) :
1877                                           errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
1878                                                           rte->eref->aliasname)),
1879                                          parser_errposition(pstate, location)));
1880                 else
1881                         ereport(ERROR,
1882                                         (errcode(ERRCODE_UNDEFINED_TABLE),
1883                                          (pstate->parentParseState ?
1884                                           errmsg("missing FROM-clause entry in subquery for table \"%s\"",
1885                                                          relation->relname) :
1886                                           errmsg("missing FROM-clause entry for table \"%s\"",
1887                                                          relation->relname)),
1888                                          parser_errposition(pstate, location)));
1889         }
1890         else
1891         {
1892                 /* just issue a warning */
1893                 ereport(NOTICE,
1894                                 (errcode(ERRCODE_UNDEFINED_TABLE),
1895                                  (pstate->parentParseState ?
1896                                   errmsg("adding missing FROM-clause entry in subquery for table \"%s\"",
1897                                                  relation->relname) :
1898                                   errmsg("adding missing FROM-clause entry for table \"%s\"",
1899                                                  relation->relname)),
1900                                  (badAlias ?
1901                                   errhint("Perhaps you meant to reference the table alias \"%s\".",
1902                                                   badAlias) :
1903                                   (rte ?
1904                                    errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
1905                                                    rte->eref->aliasname) : 0)),
1906                                  parser_errposition(pstate, location)));
1907         }
1908 }