1 /*-------------------------------------------------------------------------
4 * Definitions for "primitive" node types, those that are used in more
5 * than one of the parse/plan/execute stages of the query pipeline.
6 * Currently, these are mostly nodes for executable expressions
10 * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
11 * Portions Copyright (c) 1994, Regents of the University of California
13 * $Id: primnodes.h,v 1.50 2001/01/17 06:41:31 momjian Exp $
15 *-------------------------------------------------------------------------
20 #include "access/attnum.h"
21 #include "nodes/pg_list.h"
23 /* FunctionCache is declared in utils/fcache.h */
24 typedef struct FunctionCache *FunctionCachePtr;
27 /* ----------------------------------------------------------------
29 * ----------------------------------------------------------------
33 * Resdom (Result Domain)
36 * ressortgroupref is the parse/plan-time representation of ORDER BY and
37 * GROUP BY items. Targetlist entries with ressortgroupref=0 are not
38 * sort/group items. If ressortgroupref>0, then this item is an ORDER BY or
39 * GROUP BY value. No two entries in a targetlist may have the same nonzero
40 * ressortgroupref --- but there is no particular meaning to the nonzero
41 * values, except as tags. (For example, one must not assume that lower
42 * ressortgroupref means a more significant sort key.) The order of the
43 * associated SortClause or GroupClause lists determine the semantics.
45 * reskey and reskeyop are the execution-time representation of sorting.
46 * reskey must be zero in any non-sort-key item. The reskey of sort key
47 * targetlist items for a sort plan node is 1,2,...,n for the n sort keys.
48 * The reskeyop of each such targetlist item is the sort operator's
49 * regproc OID. reskeyop will be zero in non-sort-key items.
51 * Both reskey and reskeyop are typically zero during parse/plan stages.
52 * The executor does not pay any attention to ressortgroupref.
58 AttrNumber resno; /* attribute number */
59 Oid restype; /* type of the value */
60 int32 restypmod; /* type-specific modifier of the value */
61 char *resname; /* name of the resdom (could be NULL) */
62 Index ressortgroupref;
63 /* nonzero if referenced by a sort/group clause */
64 Index reskey; /* order of key in a sort (for those > 0) */
65 Oid reskeyop; /* sort operator's regproc Oid */
66 bool resjunk; /* set to true to eliminate the attribute
67 * from final target list */
76 bool fj_initialized; /* true if the Fjoin has already been
77 * initialized for the current target
79 int fj_nNodes; /* The number of Iter nodes returning
80 * sets that the node will flatten */
81 List *fj_innerNode; /* exactly one Iter node. We eval every
82 * node in the outerList once then eval
83 * the inner node to completion pair the
84 * outerList result vector with each inner
85 * result to form the full result. When
86 * the inner has been exhausted, we get
87 * the next outer result vector and reset
90 DatumPtr fj_results; /* The complete (flattened) result vector */
91 BoolPtr fj_alwaysDone; /* a null vector to indicate sets with a
92 * cardinality of 0, we treat them as the
98 /* ----------------------------------------------------------------
99 * node types for executable expressions
100 * ----------------------------------------------------------------
108 OP_EXPR, FUNC_EXPR, OR_EXPR, AND_EXPR, NOT_EXPR, SUBPLAN_EXPR
114 Oid typeOid; /* oid of the type of this expression */
115 OpType opType; /* type of this expression */
116 Node *oper; /* operator node if needed (Oper, Func, or
118 List *args; /* arguments to this expression */
124 * Note: during parsing/planning, varnoold/varoattno are always just copies
125 * of varno/varattno. At the tail end of planning, Var nodes appearing in
126 * upper-level plan nodes are reassigned to point to the outputs of their
127 * subplans; for example, in a join node varno becomes INNER or OUTER and
128 * varattno becomes the index of the proper element of that subplan's target
129 * list. But varnoold/varoattno continue to hold the original values.
130 * The code doesn't really need varnoold/varoattno, but they are very useful
131 * for debugging and interpreting completed plans, so we keep them around.
137 #define PRS2_OLD_VARNO 1
138 #define PRS2_NEW_VARNO 2
143 Index varno; /* index of this var's relation in the range
144 * table (could also be INNER or OUTER) */
145 AttrNumber varattno; /* attribute number of this var, or zero for all */
146 Oid vartype; /* pg_type tuple OID for the type of this var */
147 int32 vartypmod; /* pg_attribute typmod value */
149 /* for subquery variables referencing outer
150 * relations; 0 in a normal var, >0 means N
152 Index varnoold; /* original value of varno, for debugging */
153 AttrNumber varoattno; /* original value of varattno */
159 * NOTE: in the good old days 'opno' used to be both (or either, or
160 * neither) the pg_operator oid, and/or the pg_proc oid depending
161 * on the postgres module in question (parser->pg_operator,
162 * executor->pg_proc, planner->both), the mood of the programmer,
163 * and the phase of the moon (rumors that it was also depending on the day
164 * of the week are probably false). To make things even more postgres-like
165 * (i.e. a mess) some comments were referring to 'opno' using the name
166 * 'opid'. Anyway, now we have two separate fields, and of course that
167 * immediately removes all bugs from the code... [ sp :-) ].
169 * Note also that opid is not necessarily filled in immediately on creation
170 * of the node. The planner makes sure it is valid before passing the node
171 * tree to the executor, but during parsing/planning opid is typically 0.
177 Oid opno; /* PG_OPERATOR OID of the operator */
178 Oid opid; /* PG_PROC OID for the operator's underlying
181 /* PG_TYPE OID of the operator's return value */
182 FunctionCachePtr op_fcache;
183 /* runtime state while running the function */
193 Oid consttype; /* PG_TYPE OID of the constant's value */
194 int constlen; /* length in bytes of the constant's value */
195 Datum constvalue; /* the constant's value */
196 bool constisnull; /* whether the constant is null (if true,
197 * the other fields are undefined) */
198 bool constbyval; /* whether the information in constvalue
199 * if passed by value. If true, then all
200 * the information is stored in the datum.
201 * If false, then the datum contains a pointer
202 * to the information. */
203 bool constisset; /* whether the const represents a set.
204 * The const value corresponding will be the
205 * query that defines the set. */
211 * paramkind - specifies the kind of parameter. The possible values
212 * for this field are specified in "params.h", and they are:
214 * PARAM_NAMED: The parameter has a name, i.e. something
215 * like `$.salary' or `$.foobar'.
216 * In this case field `paramname' must be a valid Name.
218 * PARAM_NUM: The parameter has only a numeric identifier,
219 * i.e. something like `$1', `$2' etc.
220 * The number is contained in the `paramid' field.
222 * PARAM_NEW: Used in PRS2 rule, similar to PARAM_NAMED.
223 * The `paramname' and `paramid' refer to the "NEW" tuple
224 * The `pramname' is the attribute name and `paramid'
225 * is the attribute number.
227 * PARAM_OLD: Same as PARAM_NEW, but in this case we refer to
234 int paramkind; /* specifies the kind of parameter. See above */
235 AttrNumber paramid; /* numeric identifier for literal-constant
236 * parameters ("$1") */
237 char *paramname; /* attribute name for tuple-substitution
238 * parameters ("$.foo") */
239 Oid paramtype; /* PG_TYPE OID of the parameter's value */
249 Oid funcid; /* PG_PROC OID of the function */
250 Oid functype; /* PG_TYPE OID of the function's return value */
251 FunctionCachePtr func_fcache;
252 /* runtime state while running this function.
253 * Where we are in the execution of the function
254 * if it returns more than one value, etc.
255 * See utils/fcache.h */
260 * can anyone explain what this is for? Seems to have something to do
261 * with evaluation of functions that return sets...
268 Oid itertype; /* type of the iter expr (use for type
275 typedef struct Aggref
278 char *aggname; /* name of the aggregate */
279 Oid basetype; /* base type Oid of the aggregate
280 * (ie, input type) */
281 Oid aggtype; /* type Oid of final result of the aggregate */
282 Node *target; /* attribute or expression we are aggregating on */
283 bool aggstar; /* TRUE if argument was really '*' */
284 bool aggdistinct;/* TRUE if it's agg(DISTINCT ...) */
285 int aggno; /* workspace for executor (see nodeAgg.c) */
291 * A SubLink represents a subselect appearing in an expression, and in some
292 * cases also the combining operator(s) just above it. The subLinkType
293 * indicates the form of the expression represented:
294 * EXISTS_SUBLINK EXISTS(SELECT ...)
295 * ALL_SUBLINK (lefthand) op ALL (SELECT ...)
296 * ANY_SUBLINK (lefthand) op ANY (SELECT ...)
297 * MULTIEXPR_SUBLINK (lefthand) op (SELECT ...)
298 * EXPR_SUBLINK (SELECT with single targetlist item ...)
299 * For ALL, ANY, and MULTIEXPR, the lefthand is a list of expressions of the
300 * same length as the subselect's targetlist. MULTIEXPR will *always* have
301 * a list with more than one entry; if the subselect has just one target
302 * then the parser will create an EXPR_SUBLINK instead (and any operator
303 * above the subselect will be represented separately). Note that both
304 * MULTIEXPR and EXPR require the subselect to deliver only one row.
305 * ALL, ANY, and MULTIEXPR require the combining operators to deliver boolean
306 * results. These are reduced to one result per row using OR or AND semantics
307 * depending on the "useor" flag. ALL and ANY combine the per-row results
308 * using AND and OR semantics respectively.
310 * NOTE: lefthand and oper have varying meanings depending on where you look
311 * in the parse/plan pipeline:
312 * 1. gram.y delivers a list of the (untransformed) lefthand expressions in
313 * lefthand, and sets oper to a single A_Expr (not a list!) containing
314 * the string name of the operator, but no arguments.
315 * 2. The parser's expression transformation transforms lefthand normally,
316 * and replaces oper with a list of Oper nodes, one per lefthand
317 * expression. These nodes represent the parser's resolution of exactly
318 * which operator to apply to each pair of lefthand and targetlist
319 * expressions. However, we have not constructed actual Expr trees for
320 * these operators yet. This is the representation seen in saved rules
321 * and in the rewriter.
322 * 3. Finally, the planner converts the oper list to a list of normal Expr
323 * nodes representing the application of the operator(s) to the lefthand
324 * expressions and values from the inner targetlist. The inner
325 * targetlist items are represented by placeholder Param or Const nodes.
326 * The lefthand field is set to NIL, since its expressions are now in
327 * the Expr list. This representation is passed to the executor.
329 * Planner routines that might see either representation 2 or 3 can tell
330 * the difference by checking whether lefthand is NIL or not. Also,
331 * representation 2 appears in a "bare" SubLink, while representation 3 is
332 * found in SubLinks that are children of SubPlan nodes.
334 * In EXISTS and EXPR SubLinks, both lefthand and oper are unused and are
335 * always NIL. useor is not significant either for these sublink types.
338 typedef enum SubLinkType
340 EXISTS_SUBLINK, ALL_SUBLINK, ANY_SUBLINK, MULTIEXPR_SUBLINK, EXPR_SUBLINK
344 typedef struct SubLink
347 SubLinkType subLinkType;/* EXISTS, ALL, ANY, MULTIEXPR, EXPR */
348 bool useor; /* TRUE to combine column results with "OR"
350 List *lefthand; /* list of outer-query expressions on the left */
351 List *oper; /* list of Oper nodes for combining operators */
352 Node *subselect; /* subselect as Query* or parsetree */
356 * ArrayRef: describes an array subscripting operation
358 * An ArrayRef can describe fetching a single element from an array,
359 * fetching a subarray (array slice), storing a single element into
360 * an array, or storing a slice. The "store" cases work with an
361 * initial array value and a source value that is inserted into the
362 * appropriate part of the array; the result of the operation is an
363 * entire new modified array value.
365 * If reflowerindexpr = NIL, then we are fetching or storing a single array
366 * element at the subscripts given by refupperindexpr. Otherwise we are
367 * fetching or storing an array slice, that is a rectangular subarray
368 * with lower and upper bounds given by the index expressions.
369 * reflowerindexpr must be the same length as refupperindexpr when it
372 * Note: array types can be fixed-length (refattrlength > 0), but only
373 * when the element type is itself fixed-length. Otherwise they are
374 * varlena structures and have refattrlength = -1. In any case,
375 * an array type is never pass-by-value.
377 * Note: currently, refelemtype is NOT the element type, but the array type,
378 * when doing subarray fetch or either type of store. It would be cleaner
379 * to add more fields so we can distinguish the array element type from the
380 * result type of the ArrayRef operator...
383 typedef struct ArrayRef
386 int refattrlength; /* typlen of array type */
387 int refelemlength; /* typlen of the array element type */
388 Oid refelemtype; /* type of the result of the ArrayRef
390 bool refelembyval; /* is the element type pass-by-value? */
391 List *refupperindexpr; /* expressions that evaluate to upper
393 List *reflowerindexpr; /* expressions that evaluate to lower
395 Node *refexpr; /* the expression that evaluates to an
397 Node *refassgnexpr; /* expression for the source value, or NULL
404 * FieldSelect represents the operation of extracting one field from a tuple
405 * value. At runtime, the input expression is expected to yield a Datum
406 * that contains a pointer-to-TupleTableSlot. The specified field number
407 * is extracted and returned as a Datum.
411 typedef struct FieldSelect
414 Node *arg; /* input expression */
415 AttrNumber fieldnum; /* attribute number of field to extract */
416 Oid resulttype; /* type of the field (result type of this
418 int32 resulttypmod; /* output typmod (usually -1) */
424 * RelabelType represents a "dummy" type coercion between two binary-
425 * compatible datatypes, such as reinterpreting the result of an OID
426 * expression as an int4. It is a no-op at runtime; we only need it
427 * to provide a place to store the correct type to be attributed to
428 * the expression result during type resolution. (We can't get away
429 * with just overwriting the type field of the input expression node,
430 * so we need a separate node to show the coercion's result type.)
434 typedef struct RelabelType
437 Node *arg; /* input expression */
438 Oid resulttype; /* output type of coercion expression */
439 int32 resulttypmod; /* output typmod (usually -1) */
443 /* ----------------------------------------------------------------
444 * node types for join trees
446 * The leaves of a join tree structure are RangeTblRef nodes. Above
447 * these, JoinExpr nodes can appear to denote a specific kind of join
448 * or qualified join. Also, FromExpr nodes can appear to denote an
449 * ordinary cross-product join ("FROM foo, bar, baz WHERE ...").
450 * FromExpr is like a JoinExpr of jointype JOIN_INNER, except that it
451 * may have any number of child nodes, not just two. Also, there is an
452 * implementation-defined difference: the planner is allowed to join the
453 * children of a FromExpr using whatever join order seems good to it.
454 * At present, JoinExpr nodes are always joined in exactly the order
455 * implied by the jointree structure (except the planner may choose to
456 * swap inner and outer members of a join pair).
458 * NOTE: the top level of a Query's jointree is always a FromExpr.
459 * Even if the jointree contains no rels, there will be a FromExpr.
461 * NOTE: the qualification expressions present in JoinExpr nodes are
462 * *in addition to* the query's main WHERE clause, which appears as the
463 * qual of the top-level FromExpr. The reason for associating quals with
464 * specific nodes in the jointree is that the position of a qual is critical
465 * when outer joins are present. (If we enforce a qual too soon or too late,
466 * that may cause the outer join to produce the wrong set of NULL-extended
467 * rows.) If all joins are inner joins then all the qual positions are
468 * semantically interchangeable.
470 * NOTE: in the raw output of gram.y, a join tree contains RangeVar and
471 * RangeSubselect nodes, which are both replaced by RangeTblRef nodes
472 * during the parse analysis phase. Also, the top-level FromExpr is added
473 * during parse analysis; the grammar regards FROM and WHERE as separate.
474 * ----------------------------------------------------------------
478 * RangeTblRef - reference to an entry in the query's rangetable
480 * We could use direct pointers to the RT entries and skip having these
481 * nodes, but multiple pointers to the same node in a querytree cause
482 * lots of headaches, so it seems better to store an index into the RT.
484 typedef struct RangeTblRef
491 * JoinExpr - for SQL JOIN expressions
493 * isNatural, using, and quals are interdependent. The user can write only
494 * one of NATURAL, USING(), or ON() (this is enforced by the grammar).
495 * If he writes NATURAL then parse analysis generates the equivalent USING()
496 * list, and from that fills in "quals" with the right equality comparisons.
497 * If he writes USING() then "quals" is filled with equality comparisons.
498 * If he writes ON() then only "quals" is set. Note that NATURAL/USING
499 * are not equivalent to ON() since they also affect the output column list.
501 * alias is an Attr node representing the AS alias-clause attached to the
502 * join expression, or NULL if no clause. During parse analysis, colnames
503 * is filled with a list of String nodes giving the column names (real or
504 * alias) of the output of the join, and colvars is filled with a list of
505 * expressions that can be copied to reference the output columns.
508 typedef struct JoinExpr
511 JoinType jointype; /* type of join */
512 bool isNatural; /* Natural join? Will need to shape table */
513 Node *larg; /* left subtree */
514 Node *rarg; /* right subtree */
515 List *using; /* USING clause, if any (list of String) */
516 Node *quals; /* qualifiers on join, if any */
517 struct Attr *alias; /* user-written alias clause, if any */
518 List *colnames; /* output column names (list of String) */
519 List *colvars; /* output column nodes (list of expressions) */
523 * FromExpr - represents a FROM ... WHERE ... construct
525 * This is both more flexible than a JoinExpr (it can have any number of
526 * children, including zero) and less so --- we don't need to deal with
527 * aliases and so on. The output column set is implicitly just the union
528 * of the outputs of the children.
531 typedef struct FromExpr
534 List *fromlist; /* List of join subtrees */
535 Node *quals; /* qualifiers on join, if any */
538 #endif /* PRIMNODES_H */