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) 1996-2001, PostgreSQL Global Development Group
11 * Portions Copyright (c) 1994, Regents of the University of California
13 * $Id: primnodes.h,v 1.56 2001/10/28 06:26:07 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 * ----------------------------------------------------------------
32 /*--------------------
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 OID.
49 * 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 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 list
79 int fj_nNodes; /* The number of Iter nodes returning sets
80 * 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
89 DatumPtr fj_results; /* The complete (flattened) result vector */
90 BoolPtr fj_alwaysDone; /* a null vector to indicate sets with a
91 * cardinality of 0, we treat them as the
96 /* ----------------------------------------------------------------
97 * node types for executable expressions
98 * ----------------------------------------------------------------
106 OP_EXPR, FUNC_EXPR, OR_EXPR, AND_EXPR, NOT_EXPR, SUBPLAN_EXPR
112 Oid typeOid; /* oid of the type of this expression */
113 OpType opType; /* type of this expression */
114 Node *oper; /* operator node if needed (Oper, Func, or
116 List *args; /* arguments to this expression */
122 * Note: during parsing/planning, varnoold/varoattno are always just copies
123 * of varno/varattno. At the tail end of planning, Var nodes appearing in
124 * upper-level plan nodes are reassigned to point to the outputs of their
125 * subplans; for example, in a join node varno becomes INNER or OUTER and
126 * varattno becomes the index of the proper element of that subplan's target
127 * list. But varnoold/varoattno continue to hold the original values.
128 * The code doesn't really need varnoold/varoattno, but they are very useful
129 * for debugging and interpreting completed plans, so we keep them around.
134 #define PRS2_OLD_VARNO 1
135 #define PRS2_NEW_VARNO 2
140 Index varno; /* index of this var's relation in the
141 * range table (could also be INNER or
143 AttrNumber varattno; /* attribute number of this var, or zero
145 Oid vartype; /* pg_type tuple OID for the type of this
147 int32 vartypmod; /* pg_attribute typmod value */
151 * for subquery variables referencing outer relations; 0 in a normal
152 * var, >0 means N levels up
154 Index varnoold; /* original value of varno, for debugging */
155 AttrNumber varoattno; /* original value of varattno */
158 /*--------------------
161 * NOTE: in the good old days 'opno' used to be both (or either, or
162 * neither) the pg_operator oid, and/or the pg_proc oid depending
163 * on the postgres module in question (parser->pg_operator,
164 * executor->pg_proc, planner->both), the mood of the programmer,
165 * and the phase of the moon (rumors that it was also depending on the day
166 * of the week are probably false). To make things even more postgres-like
167 * (i.e. a mess) some comments were referring to 'opno' using the name
168 * 'opid'. Anyway, now we have two separate fields, and of course that
169 * immediately removes all bugs from the code... [ sp :-) ].
171 * Note also that opid is not necessarily filled in immediately on creation
172 * of the node. The planner makes sure it is valid before passing the node
173 * tree to the executor, but during parsing/planning opid is typically 0.
174 *--------------------
179 Oid opno; /* PG_OPERATOR OID of the operator */
180 Oid opid; /* PG_PROC OID for the operator's
181 * underlying function */
183 /* PG_TYPE OID of the operator's return value */
184 FunctionCachePtr op_fcache;
185 /* runtime state while running the function */
195 Oid consttype; /* PG_TYPE OID of the constant's value */
196 int constlen; /* length in bytes of the constant's value */
197 Datum constvalue; /* the constant's value */
198 bool constisnull; /* whether the constant is null (if true,
199 * the other fields are undefined) */
200 bool constbyval; /* whether the information in constvalue
201 * if passed by value. If true, then all
202 * the information is stored in the datum.
203 * If false, then the datum contains a
204 * pointer to the information. */
205 bool constisset; /* whether the const represents a set. The
206 * const value corresponding will be the
207 * query that defines the set. */
213 * paramkind - specifies the kind of parameter. The possible values
214 * for this field are specified in "params.h", and they are:
216 * PARAM_NAMED: The parameter has a name, i.e. something
217 * like `$.salary' or `$.foobar'.
218 * In this case field `paramname' must be a valid Name.
220 * PARAM_NUM: The parameter has only a numeric identifier,
221 * i.e. something like `$1', `$2' etc.
222 * The number is contained in the `paramid' field.
224 * PARAM_NEW: Used in PRS2 rule, similar to PARAM_NAMED.
225 * The `paramname' and `paramid' refer to the "NEW" tuple
226 * The `pramname' is the attribute name and `paramid'
227 * is the attribute number.
229 * PARAM_OLD: Same as PARAM_NEW, but in this case we refer to
236 int paramkind; /* specifies the kind of parameter. See
238 AttrNumber paramid; /* numeric identifier for literal-constant
239 * parameters ("$1") */
240 char *paramname; /* attribute name for tuple-substitution
241 * parameters ("$.foo") */
242 Oid paramtype; /* PG_TYPE OID of the parameter's value */
252 Oid funcid; /* PG_PROC OID of the function */
253 Oid functype; /* PG_TYPE OID of the function's return
255 FunctionCachePtr func_fcache;
258 * runtime state while running this function. Where we are in the
259 * execution of the function if it returns more than one value, etc.
266 * can anyone explain what this is for? Seems to have something to do
267 * with evaluation of functions that return sets...
274 Oid itertype; /* type of the iter expr (use for type
281 typedef struct Aggref
284 char *aggname; /* name of the aggregate */
285 Oid basetype; /* base type Oid of the aggregate (ie,
287 Oid aggtype; /* type Oid of final result of the
289 Node *target; /* attribute or expression we are
291 bool aggstar; /* TRUE if argument was really '*' */
292 bool aggdistinct; /* TRUE if it's agg(DISTINCT ...) */
293 int aggno; /* workspace for executor (see nodeAgg.c) */
299 * A SubLink represents a subselect appearing in an expression, and in some
300 * cases also the combining operator(s) just above it. The subLinkType
301 * indicates the form of the expression represented:
302 * EXISTS_SUBLINK EXISTS(SELECT ...)
303 * ALL_SUBLINK (lefthand) op ALL (SELECT ...)
304 * ANY_SUBLINK (lefthand) op ANY (SELECT ...)
305 * MULTIEXPR_SUBLINK (lefthand) op (SELECT ...)
306 * EXPR_SUBLINK (SELECT with single targetlist item ...)
307 * For ALL, ANY, and MULTIEXPR, the lefthand is a list of expressions of the
308 * same length as the subselect's targetlist. MULTIEXPR will *always* have
309 * a list with more than one entry; if the subselect has just one target
310 * then the parser will create an EXPR_SUBLINK instead (and any operator
311 * above the subselect will be represented separately). Note that both
312 * MULTIEXPR and EXPR require the subselect to deliver only one row.
313 * ALL, ANY, and MULTIEXPR require the combining operators to deliver boolean
314 * results. These are reduced to one result per row using OR or AND semantics
315 * depending on the "useor" flag. ALL and ANY combine the per-row results
316 * using AND and OR semantics respectively.
318 * NOTE: lefthand and oper have varying meanings depending on where you look
319 * in the parse/plan pipeline:
320 * 1. gram.y delivers a list of the (untransformed) lefthand expressions in
321 * lefthand, and sets oper to a single A_Expr (not a list!) containing
322 * the string name of the operator, but no arguments.
323 * 2. The parser's expression transformation transforms lefthand normally,
324 * and replaces oper with a list of Oper nodes, one per lefthand
325 * expression. These nodes represent the parser's resolution of exactly
326 * which operator to apply to each pair of lefthand and targetlist
327 * expressions. However, we have not constructed actual Expr trees for
328 * these operators yet. This is the representation seen in saved rules
329 * and in the rewriter.
330 * 3. Finally, the planner converts the oper list to a list of normal Expr
331 * nodes representing the application of the operator(s) to the lefthand
332 * expressions and values from the inner targetlist. The inner
333 * targetlist items are represented by placeholder Param or Const nodes.
334 * The lefthand field is set to NIL, since its expressions are now in
335 * the Expr list. This representation is passed to the executor.
337 * Planner routines that might see either representation 2 or 3 can tell
338 * the difference by checking whether lefthand is NIL or not. Also,
339 * representation 2 appears in a "bare" SubLink, while representation 3 is
340 * found in SubLinks that are children of SubPlan nodes.
342 * In EXISTS and EXPR SubLinks, both lefthand and oper are unused and are
343 * always NIL. useor is not significant either for these sublink types.
346 typedef enum SubLinkType
348 EXISTS_SUBLINK, ALL_SUBLINK, ANY_SUBLINK, MULTIEXPR_SUBLINK, EXPR_SUBLINK
352 typedef struct SubLink
355 SubLinkType subLinkType; /* EXISTS, ALL, ANY, MULTIEXPR, EXPR */
356 bool useor; /* TRUE to combine column results with
358 List *lefthand; /* list of outer-query expressions on the
360 List *oper; /* list of Oper nodes for combining
362 Node *subselect; /* subselect as Query* or parsetree */
366 * ArrayRef: describes an array subscripting operation
368 * An ArrayRef can describe fetching a single element from an array,
369 * fetching a subarray (array slice), storing a single element into
370 * an array, or storing a slice. The "store" cases work with an
371 * initial array value and a source value that is inserted into the
372 * appropriate part of the array; the result of the operation is an
373 * entire new modified array value.
375 * If reflowerindexpr = NIL, then we are fetching or storing a single array
376 * element at the subscripts given by refupperindexpr. Otherwise we are
377 * fetching or storing an array slice, that is a rectangular subarray
378 * with lower and upper bounds given by the index expressions.
379 * reflowerindexpr must be the same length as refupperindexpr when it
382 * Note: array types can be fixed-length (refattrlength > 0), but only
383 * when the element type is itself fixed-length. Otherwise they are
384 * varlena structures and have refattrlength = -1. In any case,
385 * an array type is never pass-by-value.
387 * Note: currently, refelemtype is NOT the element type, but the array type,
388 * when doing subarray fetch or either type of store. It would be cleaner
389 * to add more fields so we can distinguish the array element type from the
390 * result type of the ArrayRef operator...
393 typedef struct ArrayRef
396 int refattrlength; /* typlen of array type */
397 int refelemlength; /* typlen of the array element type */
398 Oid refelemtype; /* type of the result of the ArrayRef
400 bool refelembyval; /* is the element type pass-by-value? */
401 List *refupperindexpr;/* expressions that evaluate to upper
403 List *reflowerindexpr;/* expressions that evaluate to lower
405 Node *refexpr; /* the expression that evaluates to an
407 Node *refassgnexpr; /* expression for the source value, or
414 * FieldSelect represents the operation of extracting one field from a tuple
415 * value. At runtime, the input expression is expected to yield a Datum
416 * that contains a pointer-to-TupleTableSlot. The specified field number
417 * is extracted and returned as a Datum.
421 typedef struct FieldSelect
424 Node *arg; /* input expression */
425 AttrNumber fieldnum; /* attribute number of field to extract */
426 Oid resulttype; /* type of the field (result type of this
428 int32 resulttypmod; /* output typmod (usually -1) */
434 * RelabelType represents a "dummy" type coercion between two binary-
435 * compatible datatypes, such as reinterpreting the result of an OID
436 * expression as an int4. It is a no-op at runtime; we only need it
437 * to provide a place to store the correct type to be attributed to
438 * the expression result during type resolution. (We can't get away
439 * with just overwriting the type field of the input expression node,
440 * so we need a separate node to show the coercion's result type.)
444 typedef struct RelabelType
447 Node *arg; /* input expression */
448 Oid resulttype; /* output type of coercion expression */
449 int32 resulttypmod; /* output typmod (usually -1) */
453 /* ----------------------------------------------------------------
454 * node types for join trees
456 * The leaves of a join tree structure are RangeTblRef nodes. Above
457 * these, JoinExpr nodes can appear to denote a specific kind of join
458 * or qualified join. Also, FromExpr nodes can appear to denote an
459 * ordinary cross-product join ("FROM foo, bar, baz WHERE ...").
460 * FromExpr is like a JoinExpr of jointype JOIN_INNER, except that it
461 * may have any number of child nodes, not just two. Also, there is an
462 * implementation-defined difference: the planner is allowed to join the
463 * children of a FromExpr using whatever join order seems good to it.
464 * At present, JoinExpr nodes are always joined in exactly the order
465 * implied by the jointree structure (except the planner may choose to
466 * swap inner and outer members of a join pair).
468 * NOTE: the top level of a Query's jointree is always a FromExpr.
469 * Even if the jointree contains no rels, there will be a FromExpr.
471 * NOTE: the qualification expressions present in JoinExpr nodes are
472 * *in addition to* the query's main WHERE clause, which appears as the
473 * qual of the top-level FromExpr. The reason for associating quals with
474 * specific nodes in the jointree is that the position of a qual is critical
475 * when outer joins are present. (If we enforce a qual too soon or too late,
476 * that may cause the outer join to produce the wrong set of NULL-extended
477 * rows.) If all joins are inner joins then all the qual positions are
478 * semantically interchangeable.
480 * NOTE: in the raw output of gram.y, a join tree contains RangeVar and
481 * RangeSubselect nodes, which are both replaced by RangeTblRef nodes
482 * during the parse analysis phase. Also, the top-level FromExpr is added
483 * during parse analysis; the grammar regards FROM and WHERE as separate.
484 * ----------------------------------------------------------------
488 * RangeTblRef - reference to an entry in the query's rangetable
490 * We could use direct pointers to the RT entries and skip having these
491 * nodes, but multiple pointers to the same node in a querytree cause
492 * lots of headaches, so it seems better to store an index into the RT.
494 typedef struct RangeTblRef
501 * JoinExpr - for SQL JOIN expressions
503 * isNatural, using, and quals are interdependent. The user can write only
504 * one of NATURAL, USING(), or ON() (this is enforced by the grammar).
505 * If he writes NATURAL then parse analysis generates the equivalent USING()
506 * list, and from that fills in "quals" with the right equality comparisons.
507 * If he writes USING() then "quals" is filled with equality comparisons.
508 * If he writes ON() then only "quals" is set. Note that NATURAL/USING
509 * are not equivalent to ON() since they also affect the output column list.
511 * alias is an Attr node representing the AS alias-clause attached to the
512 * join expression, or NULL if no clause. NB: presence or absence of the
513 * alias has a critical impact on semantics, because a join with an alias
514 * restricts visibility of the tables/columns inside it.
516 * During parse analysis, colnames is filled with a list of String nodes
517 * giving the column names (real or alias) of the output of the join,
518 * and colvars is filled with a list of expressions that can be copied to
519 * reference the output columns.
522 typedef struct JoinExpr
525 JoinType jointype; /* type of join */
526 bool isNatural; /* Natural join? Will need to shape table */
527 Node *larg; /* left subtree */
528 Node *rarg; /* right subtree */
529 List *using; /* USING clause, if any (list of String) */
530 Node *quals; /* qualifiers on join, if any */
531 struct Attr *alias; /* user-written alias clause, if any */
532 List *colnames; /* output column names (list of String) */
533 List *colvars; /* output column nodes (list of
538 * FromExpr - represents a FROM ... WHERE ... construct
540 * This is both more flexible than a JoinExpr (it can have any number of
541 * children, including zero) and less so --- we don't need to deal with
542 * aliases and so on. The output column set is implicitly just the union
543 * of the outputs of the children.
546 typedef struct FromExpr
549 List *fromlist; /* List of join subtrees */
550 Node *quals; /* qualifiers on join, if any */
553 #endif /* PRIMNODES_H */