1 /*------------------------------------------------------------------------- 2 * 3 * primnodes.h 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 7 * and join trees. 8 * 9 * Portions Copyright (c) 2003-2021, PgPool Global Development Group * 10 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group 11 * Portions Copyright (c) 1994, Regents of the University of California 12 * 13 * src/include/nodes/primnodes.h 14 * 15 *------------------------------------------------------------------------- 16 */ 17 #ifndef PRIMNODES_H 18 #define PRIMNODES_H 19 20 #include "pg_list.h" 21 22 23 /* 24 * include/c.h 25 */ 26 typedef uint32 SubTransactionId; 27 #define InvalidSubTransactionId ((SubTransactionId) 0) 28 29 /* ---------------------------------------------------------------- 30 * node definitions 31 * ---------------------------------------------------------------- 32 */ 33 34 /* 35 * include/nodes/bitmapset.h start 36 */ 37 typedef uint32 bitmapword; /* must be an unsigned type */ 38 39 typedef struct Bitmapset 40 { 41 int nwords; /* number of words in array */ 42 bitmapword words[1]; /* really [nwords] */ 43 } Bitmapset; /* VARIABLE LENGTH STRUCT */ 44 45 extern Bitmapset *bms_copy(const Bitmapset *a); 46 47 /* include/nodes/bitmapset.h end */ 48 49 /* 50 * Alias - 51 * specifies an alias for a range variable; the alias might also 52 * specify renaming of columns within the table. 53 * 54 * Note: colnames is a list of Value nodes (always strings). In Alias structs 55 * associated with RTEs, there may be entries corresponding to dropped 56 * columns; these are normally empty strings (""). See parsenodes.h for info. 57 */ 58 typedef struct Alias 59 { 60 NodeTag type; 61 char *aliasname; /* aliased rel name (never qualified) */ 62 List *colnames; /* optional list of column aliases */ 63 } Alias; 64 65 /* What to do at commit time for temporary relations */ 66 typedef enum OnCommitAction 67 { 68 ONCOMMIT_NOOP, /* No ON COMMIT clause (do nothing) */ 69 ONCOMMIT_PRESERVE_ROWS, /* ON COMMIT PRESERVE ROWS (do nothing) */ 70 ONCOMMIT_DELETE_ROWS, /* ON COMMIT DELETE ROWS */ 71 ONCOMMIT_DROP /* ON COMMIT DROP */ 72 } OnCommitAction; 73 74 /* 75 * RangeVar - range variable, used in FROM clauses 76 * 77 * Also used to represent table names in utility statements; there, the alias 78 * field is not used, and inh tells whether to apply the operation 79 * recursively to child tables. In some contexts it is also useful to carry 80 * a TEMP table indication here. 81 */ 82 typedef struct RangeVar 83 { 84 NodeTag type; 85 char *catalogname; /* the catalog (database) name, or NULL */ 86 char *schemaname; /* the schema name, or NULL */ 87 char *relname; /* the relation/sequence name */ 88 bool inh; /* expand rel by inheritance? recursively act 89 * on children? */ 90 char relpersistence; /* see RELPERSISTENCE_* in pg_class.h */ 91 Alias *alias; /* table alias & optional column aliases */ 92 int location; /* token location, or -1 if unknown */ 93 } RangeVar; 94 95 /* 96 * TableFunc - node for a table function, such as XMLTABLE. 97 * 98 * Entries in the ns_names list are either string Value nodes containing 99 * literal namespace names, or NULL pointers to represent DEFAULT. 100 */ 101 typedef struct TableFunc 102 { 103 NodeTag type; 104 List *ns_uris; /* list of namespace URI expressions */ 105 List *ns_names; /* list of namespace names or NULL */ 106 Node *docexpr; /* input document expression */ 107 Node *rowexpr; /* row filter expression */ 108 List *colnames; /* column names (list of String) */ 109 List *coltypes; /* OID list of column type OIDs */ 110 List *coltypmods; /* integer list of column typmods */ 111 List *colcollations; /* OID list of column collation OIDs */ 112 List *colexprs; /* list of column filter expressions */ 113 List *coldefexprs; /* list of column default expressions */ 114 Bitmapset *notnulls; /* nullability flag for each output column */ 115 int ordinalitycol; /* counts from 0; -1 if none specified */ 116 int location; /* token location, or -1 if unknown */ 117 } TableFunc; 118 119 /* 120 * IntoClause - target information for SELECT INTO, CREATE TABLE AS, and 121 * CREATE MATERIALIZED VIEW 122 * 123 * For CREATE MATERIALIZED VIEW, viewQuery is the parsed-but-not-rewritten 124 * SELECT Query for the view; otherwise it's NULL. (Although it's actually 125 * Query*, we declare it as Node* to avoid a forward reference.) 126 */ 127 typedef struct IntoClause 128 { 129 NodeTag type; 130 131 RangeVar *rel; /* target relation name */ 132 List *colNames; /* column names to assign, or NIL */ 133 char *accessMethod; /* table access method */ 134 List *options; /* options from WITH clause */ 135 OnCommitAction onCommit; /* what do we do at COMMIT? */ 136 char *tableSpaceName; /* table space to use, or NULL */ 137 Node *viewQuery; /* materialized view's SELECT query */ 138 bool skipData; /* true for WITH NO DATA */ 139 } IntoClause; 140 141 142 /* ---------------------------------------------------------------- 143 * node types for executable expressions 144 * ---------------------------------------------------------------- 145 */ 146 147 /* 148 * Expr - generic superclass for executable-expression nodes 149 * 150 * All node types that are used in executable expression trees should derive 151 * from Expr (that is, have Expr as their first field). Since Expr only 152 * contains NodeTag, this is a formality, but it is an easy form of 153 * documentation. See also the ExprState node types in execnodes.h. 154 */ 155 typedef struct Expr 156 { 157 NodeTag type; 158 } Expr; 159 160 /* 161 * Var - expression node representing a variable (ie, a table column) 162 * 163 * In the parser and planner, varno and varattno identify the semantic 164 * referent, which is a base-relation column unless the reference is to a join 165 * USING column that isn't semantically equivalent to either join input column 166 * (because it is a FULL join or the input column requires a type coercion). 167 * In those cases varno and varattno refer to the JOIN RTE. (Early in the 168 * planner, we replace such join references by the implied expression; but up 169 * till then we want join reference Vars to keep their original identity for 170 * query-printing purposes.) 171 * 172 * At the end of planning, Var nodes appearing in upper-level plan nodes are 173 * reassigned to point to the outputs of their subplans; for example, in a 174 * join node varno becomes INNER_VAR or OUTER_VAR and varattno becomes the 175 * index of the proper element of that subplan's target list. Similarly, 176 * INDEX_VAR is used to identify Vars that reference an index column rather 177 * than a heap column. (In ForeignScan and CustomScan plan nodes, INDEX_VAR 178 * is abused to signify references to columns of a custom scan tuple type.) 179 * 180 * ROWID_VAR is used in the planner to identify nonce variables that carry 181 * row identity information during UPDATE/DELETE. This value should never 182 * be seen outside the planner. 183 * 184 * In the parser, varnosyn and varattnosyn are either identical to 185 * varno/varattno, or they specify the column's position in an aliased JOIN 186 * RTE that hides the semantic referent RTE's refname. This is a syntactic 187 * identifier as opposed to the semantic identifier; it tells ruleutils.c 188 * how to print the Var properly. varnosyn/varattnosyn retain their values 189 * throughout planning and execution, so they are particularly helpful to 190 * identify Vars when debugging. Note, however, that a Var that is generated 191 * in the planner and doesn't correspond to any simple relation column may 192 * have varnosyn = varattnosyn = 0. 193 */ 194 #define INNER_VAR 65000 /* reference to inner subplan */ 195 #define OUTER_VAR 65001 /* reference to outer subplan */ 196 #define INDEX_VAR 65002 /* reference to index column */ 197 #define ROWID_VAR 65003 /* row identity column during planning */ 198 199 #define IS_SPECIAL_VARNO(varno) ((varno) >= INNER_VAR) 200 201 /* Symbols for the indexes of the special RTE entries in rules */ 202 #define PRS2_OLD_VARNO 1 203 #define PRS2_NEW_VARNO 2 204 205 typedef struct Var 206 { 207 Expr xpr; 208 Index varno; /* index of this var's relation in the range 209 * table, or INNER_VAR/OUTER_VAR/INDEX_VAR */ 210 AttrNumber varattno; /* attribute number of this var, or zero for 211 * all attrs ("whole-row Var") */ 212 Oid vartype; /* pg_type OID for the type of this var */ 213 int32 vartypmod; /* pg_attribute typmod value */ 214 Oid varcollid; /* OID of collation, or InvalidOid if none */ 215 Index varlevelsup; /* for subquery variables referencing outer 216 * relations; 0 in a normal var, >0 means N 217 * levels up */ 218 Index varnosyn; /* syntactic relation index (0 if unknown) */ 219 AttrNumber varattnosyn; /* syntactic attribute number */ 220 int location; /* token location, or -1 if unknown */ 221 } Var; 222 223 /* 224 * Const 225 * 226 * Note: for varlena data types, we make a rule that a Const node's value 227 * must be in non-extended form (4-byte header, no compression or external 228 * references). This ensures that the Const node is self-contained and makes 229 * it more likely that equal() will see logically identical values as equal. 230 */ 231 typedef struct Const 232 { 233 Expr xpr; 234 Oid consttype; /* pg_type OID of the constant's datatype */ 235 int32 consttypmod; /* typmod value, if any */ 236 Oid constcollid; /* OID of collation, or InvalidOid if none */ 237 int constlen; /* typlen of the constant's datatype */ 238 Datum constvalue; /* the constant's value */ 239 bool constisnull; /* whether the constant is null (if true, 240 * constvalue is undefined) */ 241 bool constbyval; /* whether this datatype is passed by value. 242 * If true, then all the information is stored 243 * in the Datum. If false, then the Datum 244 * contains a pointer to the information. */ 245 int location; /* token location, or -1 if unknown */ 246 } Const; 247 248 /* 249 * Param 250 * 251 * paramkind specifies the kind of parameter. The possible values 252 * for this field are: 253 * 254 * PARAM_EXTERN: The parameter value is supplied from outside the plan. 255 * Such parameters are numbered from 1 to n. 256 * 257 * PARAM_EXEC: The parameter is an internal executor parameter, used 258 * for passing values into and out of sub-queries or from 259 * nestloop joins to their inner scans. 260 * For historical reasons, such parameters are numbered from 0. 261 * These numbers are independent of PARAM_EXTERN numbers. 262 * 263 * PARAM_SUBLINK: The parameter represents an output column of a SubLink 264 * node's sub-select. The column number is contained in the 265 * `paramid' field. (This type of Param is converted to 266 * PARAM_EXEC during planning.) 267 * 268 * PARAM_MULTIEXPR: Like PARAM_SUBLINK, the parameter represents an 269 * output column of a SubLink node's sub-select, but here, the 270 * SubLink is always a MULTIEXPR SubLink. The high-order 16 bits 271 * of the `paramid' field contain the SubLink's subLinkId, and 272 * the low-order 16 bits contain the column number. (This type 273 * of Param is also converted to PARAM_EXEC during planning.) 274 */ 275 typedef enum ParamKind 276 { 277 PARAM_EXTERN, 278 PARAM_EXEC, 279 PARAM_SUBLINK, 280 PARAM_MULTIEXPR 281 } ParamKind; 282 283 typedef struct Param 284 { 285 Expr xpr; 286 ParamKind paramkind; /* kind of parameter. See above */ 287 int paramid; /* numeric ID for parameter */ 288 Oid paramtype; /* pg_type OID of parameter's datatype */ 289 int32 paramtypmod; /* typmod value, if known */ 290 Oid paramcollid; /* OID of collation, or InvalidOid if none */ 291 int location; /* token location, or -1 if unknown */ 292 } Param; 293 294 /* 295 * Aggref 296 * 297 * The aggregate's args list is a targetlist, ie, a list of TargetEntry nodes. 298 * 299 * For a normal (non-ordered-set) aggregate, the non-resjunk TargetEntry nodes 300 * represent the aggregate's regular arguments (if any) and resjunk TLEs can 301 * be added at the end to represent ORDER BY expressions that are not also 302 * arguments. As in a top-level Query, the TLEs can be marked with 303 * ressortgroupref indexes to let them be referenced by SortGroupClause 304 * entries in the aggorder and/or aggdistinct lists. This represents ORDER BY 305 * and DISTINCT operations to be applied to the aggregate input rows before 306 * they are passed to the transition function. The grammar only allows a 307 * simple "DISTINCT" specifier for the arguments, but we use the full 308 * query-level representation to allow more code sharing. 309 * 310 * For an ordered-set aggregate, the args list represents the WITHIN GROUP 311 * (aggregated) arguments, all of which will be listed in the aggorder list. 312 * DISTINCT is not supported in this case, so aggdistinct will be NIL. 313 * The direct arguments appear in aggdirectargs (as a list of plain 314 * expressions, not TargetEntry nodes). 315 * 316 * aggtranstype is the data type of the state transition values for this 317 * aggregate (resolved to an actual type, if agg's transtype is polymorphic). 318 * This is determined during planning and is InvalidOid before that. 319 * 320 * aggargtypes is an OID list of the data types of the direct and regular 321 * arguments. Normally it's redundant with the aggdirectargs and args lists, 322 * but in a combining aggregate, it's not because the args list has been 323 * replaced with a single argument representing the partial-aggregate 324 * transition values. 325 * 326 * aggsplit indicates the expected partial-aggregation mode for the Aggref's 327 * parent plan node. It's always set to AGGSPLIT_SIMPLE in the parser, but 328 * the planner might change it to something else. We use this mainly as 329 * a crosscheck that the Aggrefs match the plan; but note that when aggsplit 330 * indicates a non-final mode, aggtype reflects the transition data type 331 * not the SQL-level output type of the aggregate. 332 * 333 * aggno and aggtransno are -1 in the parse stage, and are set in planning. 334 * Aggregates with the same 'aggno' represent the same aggregate expression, 335 * and can share the result. Aggregates with same 'transno' but different 336 * 'aggno' can share the same transition state, only the final function needs 337 * to be called separately. 338 */ 339 typedef struct Aggref 340 { 341 Expr xpr; 342 Oid aggfnoid; /* pg_proc Oid of the aggregate */ 343 Oid aggtype; /* type Oid of result of the aggregate */ 344 Oid aggcollid; /* OID of collation of result */ 345 Oid inputcollid; /* OID of collation that function should use */ 346 Oid aggtranstype; /* type Oid of aggregate's transition value */ 347 List *aggargtypes; /* type Oids of direct and aggregated args */ 348 List *aggdirectargs; /* direct arguments, if an ordered-set agg */ 349 List *args; /* aggregated arguments and sort expressions */ 350 List *aggorder; /* ORDER BY (list of SortGroupClause) */ 351 List *aggdistinct; /* DISTINCT (list of SortGroupClause) */ 352 Expr *aggfilter; /* FILTER expression, if any */ 353 bool aggstar; /* true if argument list was really '*' */ 354 bool aggvariadic; /* true if variadic arguments have been 355 * combined into an array last argument */ 356 char aggkind; /* aggregate kind (see pg_aggregate.h) */ 357 Index agglevelsup; /* > 0 if agg belongs to outer query */ 358 AggSplit aggsplit; /* expected agg-splitting mode of parent Agg */ 359 int aggno; /* unique ID within the Agg node */ 360 int aggtransno; /* unique ID of transition state in the Agg */ 361 int location; /* token location, or -1 if unknown */ 362 } Aggref; 363 364 /* 365 * GroupingFunc 366 * 367 * A GroupingFunc is a GROUPING(...) expression, which behaves in many ways 368 * like an aggregate function (e.g. it "belongs" to a specific query level, 369 * which might not be the one immediately containing it), but also differs in 370 * an important respect: it never evaluates its arguments, they merely 371 * designate expressions from the GROUP BY clause of the query level to which 372 * it belongs. 373 * 374 * The spec defines the evaluation of GROUPING() purely by syntactic 375 * replacement, but we make it a real expression for optimization purposes so 376 * that one Agg node can handle multiple grouping sets at once. Evaluating the 377 * result only needs the column positions to check against the grouping set 378 * being projected. However, for EXPLAIN to produce meaningful output, we have 379 * to keep the original expressions around, since expression deparse does not 380 * give us any feasible way to get at the GROUP BY clause. 381 * 382 * Also, we treat two GroupingFunc nodes as equal if they have equal arguments 383 * lists and agglevelsup, without comparing the refs and cols annotations. 384 * 385 * In raw parse output we have only the args list; parse analysis fills in the 386 * refs list, and the planner fills in the cols list. 387 */ 388 typedef struct GroupingFunc 389 { 390 Expr xpr; 391 List *args; /* arguments, not evaluated but kept for 392 * benefit of EXPLAIN etc. */ 393 List *refs; /* ressortgrouprefs of arguments */ 394 List *cols; /* actual column positions set by planner */ 395 Index agglevelsup; /* same as Aggref.agglevelsup */ 396 int location; /* token location */ 397 } GroupingFunc; 398 399 /* 400 * WindowFunc 401 */ 402 typedef struct WindowFunc 403 { 404 Expr xpr; 405 Oid winfnoid; /* pg_proc Oid of the function */ 406 Oid wintype; /* type Oid of result of the window function */ 407 Oid wincollid; /* OID of collation of result */ 408 Oid inputcollid; /* OID of collation that function should use */ 409 List *args; /* arguments to the window function */ 410 Expr *aggfilter; /* FILTER expression, if any */ 411 Index winref; /* index of associated WindowClause */ 412 bool winstar; /* true if argument list was really '*' */ 413 bool winagg; /* is function a simple aggregate? */ 414 int location; /* token location, or -1 if unknown */ 415 } WindowFunc; 416 417 /* 418 * SubscriptingRef: describes a subscripting operation over a container 419 * (array, etc). 420 * 421 * A SubscriptingRef can describe fetching a single element from a container, 422 * fetching a part of a container (e.g. an array slice), storing a single 423 * element into a container, or storing a slice. The "store" cases work with 424 * an initial container value and a source value that is inserted into the 425 * appropriate part of the container; the result of the operation is an 426 * entire new modified container value. 427 * 428 * If reflowerindexpr = NIL, then we are fetching or storing a single container 429 * element at the subscripts given by refupperindexpr. Otherwise we are 430 * fetching or storing a container slice, that is a rectangular subcontainer 431 * with lower and upper bounds given by the index expressions. 432 * reflowerindexpr must be the same length as refupperindexpr when it 433 * is not NIL. 434 * 435 * In the slice case, individual expressions in the subscript lists can be 436 * NULL, meaning "substitute the array's current lower or upper bound". 437 * (Non-array containers may or may not support this.) 438 * 439 * refcontainertype is the actual container type that determines the 440 * subscripting semantics. (This will generally be either the exposed type of 441 * refexpr, or the base type if that is a domain.) refelemtype is the type of 442 * the container's elements; this is saved for the use of the subscripting 443 * functions, but is not used by the core code. refrestype, reftypmod, and 444 * refcollid describe the type of the SubscriptingRef's result. In a store 445 * expression, refrestype will always match refcontainertype; in a fetch, 446 * it could be refelemtype for an element fetch, or refcontainertype for a 447 * slice fetch, or possibly something else as determined by type-specific 448 * subscripting logic. Likewise, reftypmod and refcollid will match the 449 * container's properties in a store, but could be different in a fetch. 450 * 451 * Note: for the cases where a container is returned, if refexpr yields a R/W 452 * expanded container, then the implementation is allowed to modify that 453 * object in-place and return the same object. 454 */ 455 typedef struct SubscriptingRef 456 { 457 Expr xpr; 458 Oid refcontainertype; /* type of the container proper */ 459 Oid refelemtype; /* the container type's pg_type.typelem */ 460 Oid refrestype; /* type of the SubscriptingRef's result */ 461 int32 reftypmod; /* typmod of the result */ 462 Oid refcollid; /* collation of result, or InvalidOid if none */ 463 List *refupperindexpr; /* expressions that evaluate to upper 464 * container indexes */ 465 List *reflowerindexpr; /* expressions that evaluate to lower 466 * container indexes, or NIL for single 467 * container element */ 468 Expr *refexpr; /* the expression that evaluates to a 469 * container value */ 470 Expr *refassgnexpr; /* expression for the source value, or NULL if 471 * fetch */ 472 } SubscriptingRef; 473 474 /* 475 * CoercionContext - distinguishes the allowed set of type casts 476 * 477 * NB: ordering of the alternatives is significant; later (larger) values 478 * allow more casts than earlier ones. 479 */ 480 typedef enum CoercionContext 481 { 482 COERCION_IMPLICIT, /* coercion in context of expression */ 483 COERCION_ASSIGNMENT, /* coercion in context of assignment */ 484 COERCION_PLPGSQL, /* if no assignment cast, use CoerceViaIO */ 485 COERCION_EXPLICIT /* explicit cast operation */ 486 } CoercionContext; 487 488 /* 489 * CoercionForm - how to display a FuncExpr or related node 490 * 491 * "Coercion" is a bit of a misnomer, since this value records other 492 * special syntaxes besides casts, but for now we'll keep this naming. 493 * 494 * NB: equal() ignores CoercionForm fields, therefore this *must* not carry 495 * any semantically significant information. We need that behavior so that 496 * the planner will consider equivalent implicit and explicit casts to be 497 * equivalent. In cases where those actually behave differently, the coercion 498 * function's arguments will be different. 499 */ 500 typedef enum CoercionForm 501 { 502 COERCE_EXPLICIT_CALL, /* display as a function call */ 503 COERCE_EXPLICIT_CAST, /* display as an explicit cast */ 504 COERCE_IMPLICIT_CAST, /* implicit cast, so hide it */ 505 COERCE_SQL_SYNTAX /* display with SQL-mandated special syntax */ 506 } CoercionForm; 507 508 /* 509 * FuncExpr - expression node for a function call 510 */ 511 typedef struct FuncExpr 512 { 513 Expr xpr; 514 Oid funcid; /* PG_PROC OID of the function */ 515 Oid funcresulttype; /* PG_TYPE OID of result value */ 516 bool funcretset; /* true if function returns set */ 517 bool funcvariadic; /* true if variadic arguments have been 518 * combined into an array last argument */ 519 CoercionForm funcformat; /* how to display this function call */ 520 Oid funccollid; /* OID of collation of result */ 521 Oid inputcollid; /* OID of collation that function should use */ 522 List *args; /* arguments to the function */ 523 int location; /* token location, or -1 if unknown */ 524 } FuncExpr; 525 526 /* 527 * NamedArgExpr - a named argument of a function 528 * 529 * This node type can only appear in the args list of a FuncCall or FuncExpr 530 * node. We support pure positional call notation (no named arguments), 531 * named notation (all arguments are named), and mixed notation (unnamed 532 * arguments followed by named ones). 533 * 534 * Parse analysis sets argnumber to the positional index of the argument, 535 * but doesn't rearrange the argument list. 536 * 537 * The planner will convert argument lists to pure positional notation 538 * during expression preprocessing, so execution never sees a NamedArgExpr. 539 */ 540 typedef struct NamedArgExpr 541 { 542 Expr xpr; 543 Expr *arg; /* the argument expression */ 544 char *name; /* the name */ 545 int argnumber; /* argument's number in positional notation */ 546 int location; /* argument name location, or -1 if unknown */ 547 } NamedArgExpr; 548 549 /* 550 * OpExpr - expression node for an operator invocation 551 * 552 * Semantically, this is essentially the same as a function call. 553 * 554 * Note that opfuncid is not necessarily filled in immediately on creation 555 * of the node. The planner makes sure it is valid before passing the node 556 * tree to the executor, but during parsing/planning opfuncid can be 0. 557 */ 558 typedef struct OpExpr 559 { 560 Expr xpr; 561 Oid opno; /* PG_OPERATOR OID of the operator */ 562 Oid opfuncid; /* PG_PROC OID of underlying function */ 563 Oid opresulttype; /* PG_TYPE OID of result value */ 564 bool opretset; /* true if operator returns set */ 565 Oid opcollid; /* OID of collation of result */ 566 Oid inputcollid; /* OID of collation that operator should use */ 567 List *args; /* arguments to the operator (1 or 2) */ 568 int location; /* token location, or -1 if unknown */ 569 } OpExpr; 570 571 /* 572 * DistinctExpr - expression node for "x IS DISTINCT FROM y" 573 * 574 * Except for the nodetag, this is represented identically to an OpExpr 575 * referencing the "=" operator for x and y. 576 * We use "=", not the more obvious "<>", because more datatypes have "=" 577 * than "<>". This means the executor must invert the operator result. 578 * Note that the operator function won't be called at all if either input 579 * is NULL, since then the result can be determined directly. 580 */ 581 typedef OpExpr DistinctExpr; 582 583 /* 584 * NullIfExpr - a NULLIF expression 585 * 586 * Like DistinctExpr, this is represented the same as an OpExpr referencing 587 * the "=" operator for x and y. 588 */ 589 typedef OpExpr NullIfExpr; 590 591 /* 592 * ScalarArrayOpExpr - expression node for "scalar op ANY/ALL (array)" 593 * 594 * The operator must yield boolean. It is applied to the left operand 595 * and each element of the righthand array, and the results are combined 596 * with OR or AND (for ANY or ALL respectively). The node representation 597 * is almost the same as for the underlying operator, but we need a useOr 598 * flag to remember whether it's ANY or ALL, and we don't have to store 599 * the result type (or the collation) because it must be boolean. 600 * 601 * A ScalarArrayOpExpr with a valid hashfuncid is evaluated during execution 602 * by building a hash table containing the Const values from the rhs arg. 603 * This table is probed during expression evaluation. Only useOr=true 604 * ScalarArrayOpExpr with Const arrays on the rhs can have the hashfuncid 605 * field set. See convert_saop_to_hashed_saop(). 606 */ 607 typedef struct ScalarArrayOpExpr 608 { 609 Expr xpr; 610 Oid opno; /* PG_OPERATOR OID of the operator */ 611 Oid opfuncid; /* PG_PROC OID of comparison function */ 612 Oid hashfuncid; /* PG_PROC OID of hash func or InvalidOid */ 613 bool useOr; /* true for ANY, false for ALL */ 614 Oid inputcollid; /* OID of collation that operator should use */ 615 List *args; /* the scalar and array operands */ 616 int location; /* token location, or -1 if unknown */ 617 } ScalarArrayOpExpr; 618 619 /* 620 * BoolExpr - expression node for the basic Boolean operators AND, OR, NOT 621 * 622 * Notice the arguments are given as a List. For NOT, of course the list 623 * must always have exactly one element. For AND and OR, there can be two 624 * or more arguments. 625 */ 626 typedef enum BoolExprType 627 { 628 AND_EXPR, OR_EXPR, NOT_EXPR 629 } BoolExprType; 630 631 typedef struct BoolExpr 632 { 633 Expr xpr; 634 BoolExprType boolop; 635 List *args; /* arguments to this expression */ 636 int location; /* token location, or -1 if unknown */ 637 } BoolExpr; 638 639 /* 640 * SubLink 641 * 642 * A SubLink represents a subselect appearing in an expression, and in some 643 * cases also the combining operator(s) just above it. The subLinkType 644 * indicates the form of the expression represented: 645 * EXISTS_SUBLINK EXISTS(SELECT ...) 646 * ALL_SUBLINK (lefthand) op ALL (SELECT ...) 647 * ANY_SUBLINK (lefthand) op ANY (SELECT ...) 648 * ROWCOMPARE_SUBLINK (lefthand) op (SELECT ...) 649 * EXPR_SUBLINK (SELECT with single targetlist item ...) 650 * MULTIEXPR_SUBLINK (SELECT with multiple targetlist items ...) 651 * ARRAY_SUBLINK ARRAY(SELECT with single targetlist item ...) 652 * CTE_SUBLINK WITH query (never actually part of an expression) 653 * For ALL, ANY, and ROWCOMPARE, the lefthand is a list of expressions of the 654 * same length as the subselect's targetlist. ROWCOMPARE will *always* have 655 * a list with more than one entry; if the subselect has just one target 656 * then the parser will create an EXPR_SUBLINK instead (and any operator 657 * above the subselect will be represented separately). 658 * ROWCOMPARE, EXPR, and MULTIEXPR require the subselect to deliver at most 659 * one row (if it returns no rows, the result is NULL). 660 * ALL, ANY, and ROWCOMPARE require the combining operators to deliver boolean 661 * results. ALL and ANY combine the per-row results using AND and OR 662 * semantics respectively. 663 * ARRAY requires just one target column, and creates an array of the target 664 * column's type using any number of rows resulting from the subselect. 665 * 666 * SubLink is classed as an Expr node, but it is not actually executable; 667 * it must be replaced in the expression tree by a SubPlan node during 668 * planning. 669 * 670 * NOTE: in the raw output of gram.y, testexpr contains just the raw form 671 * of the lefthand expression (if any), and operName is the String name of 672 * the combining operator. Also, subselect is a raw parsetree. During parse 673 * analysis, the parser transforms testexpr into a complete boolean expression 674 * that compares the lefthand value(s) to PARAM_SUBLINK nodes representing the 675 * output columns of the subselect. And subselect is transformed to a Query. 676 * This is the representation seen in saved rules and in the rewriter. 677 * 678 * In EXISTS, EXPR, MULTIEXPR, and ARRAY SubLinks, testexpr and operName 679 * are unused and are always null. 680 * 681 * subLinkId is currently used only for MULTIEXPR SubLinks, and is zero in 682 * other SubLinks. This number identifies different multiple-assignment 683 * subqueries within an UPDATE statement's SET list. It is unique only 684 * within a particular targetlist. The output column(s) of the MULTIEXPR 685 * are referenced by PARAM_MULTIEXPR Params appearing elsewhere in the tlist. 686 * 687 * The CTE_SUBLINK case never occurs in actual SubLink nodes, but it is used 688 * in SubPlans generated for WITH subqueries. 689 */ 690 typedef enum SubLinkType 691 { 692 EXISTS_SUBLINK, 693 ALL_SUBLINK, 694 ANY_SUBLINK, 695 ROWCOMPARE_SUBLINK, 696 EXPR_SUBLINK, 697 MULTIEXPR_SUBLINK, 698 ARRAY_SUBLINK, 699 CTE_SUBLINK /* for SubPlans only */ 700 } SubLinkType; 701 702 703 typedef struct SubLink 704 { 705 Expr xpr; 706 SubLinkType subLinkType; /* see above */ 707 int subLinkId; /* ID (1..n); 0 if not MULTIEXPR */ 708 Node *testexpr; /* outer-query test for ALL/ANY/ROWCOMPARE */ 709 List *operName; /* originally specified operator name */ 710 Node *subselect; /* subselect as Query* or raw parsetree */ 711 int location; /* token location, or -1 if unknown */ 712 } SubLink; 713 714 /* 715 * SubPlan - executable expression node for a subplan (sub-SELECT) 716 * 717 * The planner replaces SubLink nodes in expression trees with SubPlan 718 * nodes after it has finished planning the subquery. SubPlan references 719 * a sub-plantree stored in the subplans list of the toplevel PlannedStmt. 720 * (We avoid a direct link to make it easier to copy expression trees 721 * without causing multiple processing of the subplan.) 722 * 723 * In an ordinary subplan, testexpr points to an executable expression 724 * (OpExpr, an AND/OR tree of OpExprs, or RowCompareExpr) for the combining 725 * operator(s); the left-hand arguments are the original lefthand expressions, 726 * and the right-hand arguments are PARAM_EXEC Param nodes representing the 727 * outputs of the sub-select. (NOTE: runtime coercion functions may be 728 * inserted as well.) This is just the same expression tree as testexpr in 729 * the original SubLink node, but the PARAM_SUBLINK nodes are replaced by 730 * suitably numbered PARAM_EXEC nodes. 731 * 732 * If the sub-select becomes an initplan rather than a subplan, the executable 733 * expression is part of the outer plan's expression tree (and the SubPlan 734 * node itself is not, but rather is found in the outer plan's initPlan 735 * list). In this case testexpr is NULL to avoid duplication. 736 * 737 * The planner also derives lists of the values that need to be passed into 738 * and out of the subplan. Input values are represented as a list "args" of 739 * expressions to be evaluated in the outer-query context (currently these 740 * args are always just Vars, but in principle they could be any expression). 741 * The values are assigned to the global PARAM_EXEC params indexed by parParam 742 * (the parParam and args lists must have the same ordering). setParam is a 743 * list of the PARAM_EXEC params that are computed by the sub-select, if it 744 * is an initplan; they are listed in order by sub-select output column 745 * position. (parParam and setParam are integer Lists, not Bitmapsets, 746 * because their ordering is significant.) 747 * 748 * Also, the planner computes startup and per-call costs for use of the 749 * SubPlan. Note that these include the cost of the subquery proper, 750 * evaluation of the testexpr if any, and any hashtable management overhead. 751 */ 752 typedef struct SubPlan 753 { 754 Expr xpr; 755 /* Fields copied from original SubLink: */ 756 SubLinkType subLinkType; /* see above */ 757 /* The combining operators, transformed to an executable expression: */ 758 Node *testexpr; /* OpExpr or RowCompareExpr expression tree */ 759 List *paramIds; /* IDs of Params embedded in the above */ 760 /* Identification of the Plan tree to use: */ 761 int plan_id; /* Index (from 1) in PlannedStmt.subplans */ 762 /* Identification of the SubPlan for EXPLAIN and debugging purposes: */ 763 char *plan_name; /* A name assigned during planning */ 764 /* Extra data useful for determining subplan's output type: */ 765 Oid firstColType; /* Type of first column of subplan result */ 766 int32 firstColTypmod; /* Typmod of first column of subplan result */ 767 Oid firstColCollation; /* Collation of first column of subplan 768 * result */ 769 /* Information about execution strategy: */ 770 bool useHashTable; /* true to store subselect output in a hash 771 * table (implies we are doing "IN") */ 772 bool unknownEqFalse; /* true if it's okay to return FALSE when the 773 * spec result is UNKNOWN; this allows much 774 * simpler handling of null values */ 775 bool parallel_safe; /* is the subplan parallel-safe? */ 776 /* Note: parallel_safe does not consider contents of testexpr or args */ 777 /* Information for passing params into and out of the subselect: */ 778 /* setParam and parParam are lists of integers (param IDs) */ 779 List *setParam; /* initplan subqueries have to set these 780 * Params for parent plan */ 781 List *parParam; /* indices of input Params from parent plan */ 782 List *args; /* exprs to pass as parParam values */ 783 /* Estimated execution costs: */ 784 Cost startup_cost; /* one-time setup cost */ 785 Cost per_call_cost; /* cost for each subplan evaluation */ 786 } SubPlan; 787 788 /* 789 * AlternativeSubPlan - expression node for a choice among SubPlans 790 * 791 * This is used only transiently during planning: by the time the plan 792 * reaches the executor, all AlternativeSubPlan nodes have been removed. 793 * 794 * The subplans are given as a List so that the node definition need not 795 * change if there's ever more than two alternatives. For the moment, 796 * though, there are always exactly two; and the first one is the fast-start 797 * plan. 798 */ 799 typedef struct AlternativeSubPlan 800 { 801 Expr xpr; 802 List *subplans; /* SubPlan(s) with equivalent results */ 803 } AlternativeSubPlan; 804 805 /* ---------------- 806 * FieldSelect 807 * 808 * FieldSelect represents the operation of extracting one field from a tuple 809 * value. At runtime, the input expression is expected to yield a rowtype 810 * Datum. The specified field number is extracted and returned as a Datum. 811 * ---------------- 812 */ 813 814 typedef struct FieldSelect 815 { 816 Expr xpr; 817 Expr *arg; /* input expression */ 818 AttrNumber fieldnum; /* attribute number of field to extract */ 819 Oid resulttype; /* type of the field (result type of this 820 * node) */ 821 int32 resulttypmod; /* output typmod (usually -1) */ 822 Oid resultcollid; /* OID of collation of the field */ 823 } FieldSelect; 824 825 /* ---------------- 826 * FieldStore 827 * 828 * FieldStore represents the operation of modifying one field in a tuple 829 * value, yielding a new tuple value (the input is not touched!). Like 830 * the assign case of SubscriptingRef, this is used to implement UPDATE of a 831 * portion of a column. 832 * 833 * resulttype is always a named composite type (not a domain). To update 834 * a composite domain value, apply CoerceToDomain to the FieldStore. 835 * 836 * A single FieldStore can actually represent updates of several different 837 * fields. The parser only generates FieldStores with single-element lists, 838 * but the planner will collapse multiple updates of the same base column 839 * into one FieldStore. 840 * ---------------- 841 */ 842 843 typedef struct FieldStore 844 { 845 Expr xpr; 846 Expr *arg; /* input tuple value */ 847 List *newvals; /* new value(s) for field(s) */ 848 List *fieldnums; /* integer list of field attnums */ 849 Oid resulttype; /* type of result (same as type of arg) */ 850 /* Like RowExpr, we deliberately omit a typmod and collation here */ 851 } FieldStore; 852 853 /* ---------------- 854 * RelabelType 855 * 856 * RelabelType represents a "dummy" type coercion between two binary- 857 * compatible datatypes, such as reinterpreting the result of an OID 858 * expression as an int4. It is a no-op at runtime; we only need it 859 * to provide a place to store the correct type to be attributed to 860 * the expression result during type resolution. (We can't get away 861 * with just overwriting the type field of the input expression node, 862 * so we need a separate node to show the coercion's result type.) 863 * ---------------- 864 */ 865 866 typedef struct RelabelType 867 { 868 Expr xpr; 869 Expr *arg; /* input expression */ 870 Oid resulttype; /* output type of coercion expression */ 871 int32 resulttypmod; /* output typmod (usually -1) */ 872 Oid resultcollid; /* OID of collation, or InvalidOid if none */ 873 CoercionForm relabelformat; /* how to display this node */ 874 int location; /* token location, or -1 if unknown */ 875 } RelabelType; 876 877 /* ---------------- 878 * CoerceViaIO 879 * 880 * CoerceViaIO represents a type coercion between two types whose textual 881 * representations are compatible, implemented by invoking the source type's 882 * typoutput function then the destination type's typinput function. 883 * ---------------- 884 */ 885 886 typedef struct CoerceViaIO 887 { 888 Expr xpr; 889 Expr *arg; /* input expression */ 890 Oid resulttype; /* output type of coercion */ 891 /* output typmod is not stored, but is presumed -1 */ 892 Oid resultcollid; /* OID of collation, or InvalidOid if none */ 893 CoercionForm coerceformat; /* how to display this node */ 894 int location; /* token location, or -1 if unknown */ 895 } CoerceViaIO; 896 897 /* ---------------- 898 * ArrayCoerceExpr 899 * 900 * ArrayCoerceExpr represents a type coercion from one array type to another, 901 * which is implemented by applying the per-element coercion expression 902 * "elemexpr" to each element of the source array. Within elemexpr, the 903 * source element is represented by a CaseTestExpr node. Note that even if 904 * elemexpr is a no-op (that is, just CaseTestExpr + RelabelType), the 905 * coercion still requires some effort: we have to fix the element type OID 906 * stored in the array header. 907 * ---------------- 908 */ 909 910 typedef struct ArrayCoerceExpr 911 { 912 Expr xpr; 913 Expr *arg; /* input expression (yields an array) */ 914 Expr *elemexpr; /* expression representing per-element work */ 915 Oid resulttype; /* output type of coercion (an array type) */ 916 int32 resulttypmod; /* output typmod (also element typmod) */ 917 Oid resultcollid; /* OID of collation, or InvalidOid if none */ 918 CoercionForm coerceformat; /* how to display this node */ 919 int location; /* token location, or -1 if unknown */ 920 } ArrayCoerceExpr; 921 922 /* ---------------- 923 * ConvertRowtypeExpr 924 * 925 * ConvertRowtypeExpr represents a type coercion from one composite type 926 * to another, where the source type is guaranteed to contain all the columns 927 * needed for the destination type plus possibly others; the columns need not 928 * be in the same positions, but are matched up by name. This is primarily 929 * used to convert a whole-row value of an inheritance child table into a 930 * valid whole-row value of its parent table's rowtype. Both resulttype 931 * and the exposed type of "arg" must be named composite types (not domains). 932 * ---------------- 933 */ 934 935 typedef struct ConvertRowtypeExpr 936 { 937 Expr xpr; 938 Expr *arg; /* input expression */ 939 Oid resulttype; /* output type (always a composite type) */ 940 /* Like RowExpr, we deliberately omit a typmod and collation here */ 941 CoercionForm convertformat; /* how to display this node */ 942 int location; /* token location, or -1 if unknown */ 943 } ConvertRowtypeExpr; 944 945 /*---------- 946 * CollateExpr - COLLATE 947 * 948 * The planner replaces CollateExpr with RelabelType during expression 949 * preprocessing, so execution never sees a CollateExpr. 950 *---------- 951 */ 952 typedef struct CollateExpr 953 { 954 Expr xpr; 955 Expr *arg; /* input expression */ 956 Oid collOid; /* collation's OID */ 957 int location; /* token location, or -1 if unknown */ 958 } CollateExpr; 959 960 /*---------- 961 * CaseExpr - a CASE expression 962 * 963 * We support two distinct forms of CASE expression: 964 * CASE WHEN boolexpr THEN expr [ WHEN boolexpr THEN expr ... ] 965 * CASE testexpr WHEN compexpr THEN expr [ WHEN compexpr THEN expr ... ] 966 * These are distinguishable by the "arg" field being NULL in the first case 967 * and the testexpr in the second case. 968 * 969 * In the raw grammar output for the second form, the condition expressions 970 * of the WHEN clauses are just the comparison values. Parse analysis 971 * converts these to valid boolean expressions of the form 972 * CaseTestExpr '=' compexpr 973 * where the CaseTestExpr node is a placeholder that emits the correct 974 * value at runtime. This structure is used so that the testexpr need be 975 * evaluated only once. Note that after parse analysis, the condition 976 * expressions always yield boolean. 977 * 978 * Note: we can test whether a CaseExpr has been through parse analysis 979 * yet by checking whether casetype is InvalidOid or not. 980 *---------- 981 */ 982 typedef struct CaseExpr 983 { 984 Expr xpr; 985 Oid casetype; /* type of expression result */ 986 Oid casecollid; /* OID of collation, or InvalidOid if none */ 987 Expr *arg; /* implicit equality comparison argument */ 988 List *args; /* the arguments (list of WHEN clauses) */ 989 Expr *defresult; /* the default result (ELSE clause) */ 990 int location; /* token location, or -1 if unknown */ 991 } CaseExpr; 992 993 /* 994 * CaseWhen - one arm of a CASE expression 995 */ 996 typedef struct CaseWhen 997 { 998 Expr xpr; 999 Expr *expr; /* condition expression */ 1000 Expr *result; /* substitution result */ 1001 int location; /* token location, or -1 if unknown */ 1002 } CaseWhen; 1003 1004 /* 1005 * Placeholder node for the test value to be processed by a CASE expression. 1006 * This is effectively like a Param, but can be implemented more simply 1007 * since we need only one replacement value at a time. 1008 * 1009 * We also abuse this node type for some other purposes, including: 1010 * * Placeholder for the current array element value in ArrayCoerceExpr; 1011 * see build_coercion_expression(). 1012 * * Nested FieldStore/SubscriptingRef assignment expressions in INSERT/UPDATE; 1013 * see transformAssignmentIndirection(). 1014 * 1015 * The uses in CaseExpr and ArrayCoerceExpr are safe only to the extent that 1016 * there is not any other CaseExpr or ArrayCoerceExpr between the value source 1017 * node and its child CaseTestExpr(s). This is true in the parse analysis 1018 * output, but the planner's function-inlining logic has to be careful not to 1019 * break it. 1020 * 1021 * The nested-assignment-expression case is safe because the only node types 1022 * that can be above such CaseTestExprs are FieldStore and SubscriptingRef. 1023 */ 1024 typedef struct CaseTestExpr 1025 { 1026 Expr xpr; 1027 Oid typeId; /* type for substituted value */ 1028 int32 typeMod; /* typemod for substituted value */ 1029 Oid collation; /* collation for the substituted value */ 1030 } CaseTestExpr; 1031 1032 /* 1033 * ArrayExpr - an ARRAY[] expression 1034 * 1035 * Note: if multidims is false, the constituent expressions all yield the 1036 * scalar type identified by element_typeid. If multidims is true, the 1037 * constituent expressions all yield arrays of element_typeid (ie, the same 1038 * type as array_typeid); at runtime we must check for compatible subscripts. 1039 */ 1040 typedef struct ArrayExpr 1041 { 1042 Expr xpr; 1043 Oid array_typeid; /* type of expression result */ 1044 Oid array_collid; /* OID of collation, or InvalidOid if none */ 1045 Oid element_typeid; /* common type of array elements */ 1046 List *elements; /* the array elements or sub-arrays */ 1047 bool multidims; /* true if elements are sub-arrays */ 1048 int location; /* token location, or -1 if unknown */ 1049 } ArrayExpr; 1050 1051 /* 1052 * RowExpr - a ROW() expression 1053 * 1054 * Note: the list of fields must have a one-for-one correspondence with 1055 * physical fields of the associated rowtype, although it is okay for it 1056 * to be shorter than the rowtype. That is, the N'th list element must 1057 * match up with the N'th physical field. When the N'th physical field 1058 * is a dropped column (attisdropped) then the N'th list element can just 1059 * be a NULL constant. (This case can only occur for named composite types, 1060 * not RECORD types, since those are built from the RowExpr itself rather 1061 * than vice versa.) It is important not to assume that length(args) is 1062 * the same as the number of columns logically present in the rowtype. 1063 * 1064 * colnames provides field names in cases where the names can't easily be 1065 * obtained otherwise. Names *must* be provided if row_typeid is RECORDOID. 1066 * If row_typeid identifies a known composite type, colnames can be NIL to 1067 * indicate the type's cataloged field names apply. Note that colnames can 1068 * be non-NIL even for a composite type, and typically is when the RowExpr 1069 * was created by expanding a whole-row Var. This is so that we can retain 1070 * the column alias names of the RTE that the Var referenced (which would 1071 * otherwise be very difficult to extract from the parsetree). Like the 1072 * args list, colnames is one-for-one with physical fields of the rowtype. 1073 */ 1074 typedef struct RowExpr 1075 { 1076 Expr xpr; 1077 List *args; /* the fields */ 1078 Oid row_typeid; /* RECORDOID or a composite type's ID */ 1079 1080 /* 1081 * row_typeid cannot be a domain over composite, only plain composite. To 1082 * create a composite domain value, apply CoerceToDomain to the RowExpr. 1083 * 1084 * Note: we deliberately do NOT store a typmod. Although a typmod will be 1085 * associated with specific RECORD types at runtime, it will differ for 1086 * different backends, and so cannot safely be stored in stored 1087 * parsetrees. We must assume typmod -1 for a RowExpr node. 1088 * 1089 * We don't need to store a collation either. The result type is 1090 * necessarily composite, and composite types never have a collation. 1091 */ 1092 CoercionForm row_format; /* how to display this node */ 1093 List *colnames; /* list of String, or NIL */ 1094 int location; /* token location, or -1 if unknown */ 1095 } RowExpr; 1096 1097 /* 1098 * RowCompareExpr - row-wise comparison, such as (a, b) <= (1, 2) 1099 * 1100 * We support row comparison for any operator that can be determined to 1101 * act like =, <>, <, <=, >, or >= (we determine this by looking for the 1102 * operator in btree opfamilies). Note that the same operator name might 1103 * map to a different operator for each pair of row elements, since the 1104 * element datatypes can vary. 1105 * 1106 * A RowCompareExpr node is only generated for the < <= > >= cases; 1107 * the = and <> cases are translated to simple AND or OR combinations 1108 * of the pairwise comparisons. However, we include = and <> in the 1109 * RowCompareType enum for the convenience of parser logic. 1110 */ 1111 typedef enum RowCompareType 1112 { 1113 /* Values of this enum are chosen to match btree strategy numbers */ 1114 ROWCOMPARE_LT = 1, /* BTLessStrategyNumber */ 1115 ROWCOMPARE_LE = 2, /* BTLessEqualStrategyNumber */ 1116 ROWCOMPARE_EQ = 3, /* BTEqualStrategyNumber */ 1117 ROWCOMPARE_GE = 4, /* BTGreaterEqualStrategyNumber */ 1118 ROWCOMPARE_GT = 5, /* BTGreaterStrategyNumber */ 1119 ROWCOMPARE_NE = 6 /* no such btree strategy */ 1120 } RowCompareType; 1121 1122 typedef struct RowCompareExpr 1123 { 1124 Expr xpr; 1125 RowCompareType rctype; /* LT LE GE or GT, never EQ or NE */ 1126 List *opnos; /* OID list of pairwise comparison ops */ 1127 List *opfamilies; /* OID list of containing operator families */ 1128 List *inputcollids; /* OID list of collations for comparisons */ 1129 List *largs; /* the left-hand input arguments */ 1130 List *rargs; /* the right-hand input arguments */ 1131 } RowCompareExpr; 1132 1133 /* 1134 * CoalesceExpr - a COALESCE expression 1135 */ 1136 typedef struct CoalesceExpr 1137 { 1138 Expr xpr; 1139 Oid coalescetype; /* type of expression result */ 1140 Oid coalescecollid; /* OID of collation, or InvalidOid if none */ 1141 List *args; /* the arguments */ 1142 int location; /* token location, or -1 if unknown */ 1143 } CoalesceExpr; 1144 1145 /* 1146 * MinMaxExpr - a GREATEST or LEAST function 1147 */ 1148 typedef enum MinMaxOp 1149 { 1150 IS_GREATEST, 1151 IS_LEAST 1152 } MinMaxOp; 1153 1154 typedef struct MinMaxExpr 1155 { 1156 Expr xpr; 1157 Oid minmaxtype; /* common type of arguments and result */ 1158 Oid minmaxcollid; /* OID of collation of result */ 1159 Oid inputcollid; /* OID of collation that function should use */ 1160 MinMaxOp op; /* function to execute */ 1161 List *args; /* the arguments */ 1162 int location; /* token location, or -1 if unknown */ 1163 } MinMaxExpr; 1164 1165 /* 1166 * SQLValueFunction - parameterless functions with special grammar productions 1167 * 1168 * The SQL standard categorizes some of these as <datetime value function> 1169 * and others as <general value specification>. We call 'em SQLValueFunctions 1170 * for lack of a better term. We store type and typmod of the result so that 1171 * some code doesn't need to know each function individually, and because 1172 * we would need to store typmod anyway for some of the datetime functions. 1173 * Note that currently, all variants return non-collating datatypes, so we do 1174 * not need a collation field; also, all these functions are stable. 1175 */ 1176 typedef enum SQLValueFunctionOp 1177 { 1178 SVFOP_CURRENT_DATE, 1179 SVFOP_CURRENT_TIME, 1180 SVFOP_CURRENT_TIME_N, 1181 SVFOP_CURRENT_TIMESTAMP, 1182 SVFOP_CURRENT_TIMESTAMP_N, 1183 SVFOP_LOCALTIME, 1184 SVFOP_LOCALTIME_N, 1185 SVFOP_LOCALTIMESTAMP, 1186 SVFOP_LOCALTIMESTAMP_N, 1187 SVFOP_CURRENT_ROLE, 1188 SVFOP_CURRENT_USER, 1189 SVFOP_USER, 1190 SVFOP_SESSION_USER, 1191 SVFOP_CURRENT_CATALOG, 1192 SVFOP_CURRENT_SCHEMA 1193 } SQLValueFunctionOp; 1194 1195 typedef struct SQLValueFunction 1196 { 1197 Expr xpr; 1198 SQLValueFunctionOp op; /* which function this is */ 1199 Oid type; /* result type/typmod */ 1200 int32 typmod; 1201 int location; /* token location, or -1 if unknown */ 1202 } SQLValueFunction; 1203 1204 /* 1205 * XmlExpr - various SQL/XML functions requiring special grammar productions 1206 * 1207 * 'name' carries the "NAME foo" argument (already XML-escaped). 1208 * 'named_args' and 'arg_names' represent an xml_attribute list. 1209 * 'args' carries all other arguments. 1210 * 1211 * Note: result type/typmod/collation are not stored, but can be deduced 1212 * from the XmlExprOp. The type/typmod fields are just used for display 1213 * purposes, and are NOT necessarily the true result type of the node. 1214 */ 1215 typedef enum XmlExprOp 1216 { 1217 IS_XMLCONCAT, /* XMLCONCAT(args) */ 1218 IS_XMLELEMENT, /* XMLELEMENT(name, xml_attributes, args) */ 1219 IS_XMLFOREST, /* XMLFOREST(xml_attributes) */ 1220 IS_XMLPARSE, /* XMLPARSE(text, is_doc, preserve_ws) */ 1221 IS_XMLPI, /* XMLPI(name [, args]) */ 1222 IS_XMLROOT, /* XMLROOT(xml, version, standalone) */ 1223 IS_XMLSERIALIZE, /* XMLSERIALIZE(is_document, xmlval) */ 1224 IS_DOCUMENT /* xmlval IS DOCUMENT */ 1225 } XmlExprOp; 1226 1227 typedef enum 1228 { 1229 XMLOPTION_DOCUMENT, 1230 XMLOPTION_CONTENT 1231 } XmlOptionType; 1232 1233 typedef struct XmlExpr 1234 { 1235 Expr xpr; 1236 XmlExprOp op; /* xml function ID */ 1237 char *name; /* name in xml(NAME foo ...) syntaxes */ 1238 List *named_args; /* non-XML expressions for xml_attributes */ 1239 List *arg_names; /* parallel list of Value strings */ 1240 List *args; /* list of expressions */ 1241 XmlOptionType xmloption; /* DOCUMENT or CONTENT */ 1242 Oid type; /* target type/typmod for XMLSERIALIZE */ 1243 int32 typmod; 1244 int location; /* token location, or -1 if unknown */ 1245 } XmlExpr; 1246 1247 /* ---------------- 1248 * NullTest 1249 * 1250 * NullTest represents the operation of testing a value for NULLness. 1251 * The appropriate test is performed and returned as a boolean Datum. 1252 * 1253 * When argisrow is false, this simply represents a test for the null value. 1254 * 1255 * When argisrow is true, the input expression must yield a rowtype, and 1256 * the node implements "row IS [NOT] NULL" per the SQL standard. This 1257 * includes checking individual fields for NULLness when the row datum 1258 * itself isn't NULL. 1259 * 1260 * NOTE: the combination of a rowtype input and argisrow==false does NOT 1261 * correspond to the SQL notation "row IS [NOT] NULL"; instead, this case 1262 * represents the SQL notation "row IS [NOT] DISTINCT FROM NULL". 1263 * ---------------- 1264 */ 1265 1266 typedef enum NullTestType 1267 { 1268 IS_NULL, IS_NOT_NULL 1269 } NullTestType; 1270 1271 typedef struct NullTest 1272 { 1273 Expr xpr; 1274 Expr *arg; /* input expression */ 1275 NullTestType nulltesttype; /* IS NULL, IS NOT NULL */ 1276 bool argisrow; /* T to perform field-by-field null checks */ 1277 int location; /* token location, or -1 if unknown */ 1278 } NullTest; 1279 1280 /* 1281 * BooleanTest 1282 * 1283 * BooleanTest represents the operation of determining whether a boolean 1284 * is TRUE, FALSE, or UNKNOWN (ie, NULL). All six meaningful combinations 1285 * are supported. Note that a NULL input does *not* cause a NULL result. 1286 * The appropriate test is performed and returned as a boolean Datum. 1287 */ 1288 1289 typedef enum BoolTestType 1290 { 1291 IS_TRUE, IS_NOT_TRUE, IS_FALSE, IS_NOT_FALSE, IS_UNKNOWN, IS_NOT_UNKNOWN 1292 } BoolTestType; 1293 1294 typedef struct BooleanTest 1295 { 1296 Expr xpr; 1297 Expr *arg; /* input expression */ 1298 BoolTestType booltesttype; /* test type */ 1299 int location; /* token location, or -1 if unknown */ 1300 } BooleanTest; 1301 1302 /* 1303 * CoerceToDomain 1304 * 1305 * CoerceToDomain represents the operation of coercing a value to a domain 1306 * type. At runtime (and not before) the precise set of constraints to be 1307 * checked will be determined. If the value passes, it is returned as the 1308 * result; if not, an error is raised. Note that this is equivalent to 1309 * RelabelType in the scenario where no constraints are applied. 1310 */ 1311 typedef struct CoerceToDomain 1312 { 1313 Expr xpr; 1314 Expr *arg; /* input expression */ 1315 Oid resulttype; /* domain type ID (result type) */ 1316 int32 resulttypmod; /* output typmod (currently always -1) */ 1317 Oid resultcollid; /* OID of collation, or InvalidOid if none */ 1318 CoercionForm coercionformat; /* how to display this node */ 1319 int location; /* token location, or -1 if unknown */ 1320 } CoerceToDomain; 1321 1322 /* 1323 * Placeholder node for the value to be processed by a domain's check 1324 * constraint. This is effectively like a Param, but can be implemented more 1325 * simply since we need only one replacement value at a time. 1326 * 1327 * Note: the typeId/typeMod/collation will be set from the domain's base type, 1328 * not the domain itself. This is because we shouldn't consider the value 1329 * to be a member of the domain if we haven't yet checked its constraints. 1330 */ 1331 typedef struct CoerceToDomainValue 1332 { 1333 Expr xpr; 1334 Oid typeId; /* type for substituted value */ 1335 int32 typeMod; /* typemod for substituted value */ 1336 Oid collation; /* collation for the substituted value */ 1337 int location; /* token location, or -1 if unknown */ 1338 } CoerceToDomainValue; 1339 1340 /* 1341 * Placeholder node for a DEFAULT marker in an INSERT or UPDATE command. 1342 * 1343 * This is not an executable expression: it must be replaced by the actual 1344 * column default expression during rewriting. But it is convenient to 1345 * treat it as an expression node during parsing and rewriting. 1346 */ 1347 typedef struct SetToDefault 1348 { 1349 Expr xpr; 1350 Oid typeId; /* type for substituted value */ 1351 int32 typeMod; /* typemod for substituted value */ 1352 Oid collation; /* collation for the substituted value */ 1353 int location; /* token location, or -1 if unknown */ 1354 } SetToDefault; 1355 1356 /* 1357 * Node representing [WHERE] CURRENT OF cursor_name 1358 * 1359 * CURRENT OF is a bit like a Var, in that it carries the rangetable index 1360 * of the target relation being constrained; this aids placing the expression 1361 * correctly during planning. We can assume however that its "levelsup" is 1362 * always zero, due to the syntactic constraints on where it can appear. 1363 * 1364 * The referenced cursor can be represented either as a hardwired string 1365 * or as a reference to a run-time parameter of type REFCURSOR. The latter 1366 * case is for the convenience of plpgsql. 1367 */ 1368 typedef struct CurrentOfExpr 1369 { 1370 Expr xpr; 1371 Index cvarno; /* RT index of target relation */ 1372 char *cursor_name; /* name of referenced cursor, or NULL */ 1373 int cursor_param; /* refcursor parameter number, or 0 */ 1374 } CurrentOfExpr; 1375 1376 /* 1377 * NextValueExpr - get next value from sequence 1378 * 1379 * This has the same effect as calling the nextval() function, but it does not 1380 * check permissions on the sequence. This is used for identity columns, 1381 * where the sequence is an implicit dependency without its own permissions. 1382 */ 1383 typedef struct NextValueExpr 1384 { 1385 Expr xpr; 1386 Oid seqid; 1387 Oid typeId; 1388 } NextValueExpr; 1389 1390 /* 1391 * InferenceElem - an element of a unique index inference specification 1392 * 1393 * This mostly matches the structure of IndexElems, but having a dedicated 1394 * primnode allows for a clean separation between the use of index parameters 1395 * by utility commands, and this node. 1396 */ 1397 typedef struct InferenceElem 1398 { 1399 Expr xpr; 1400 Node *expr; /* expression to infer from, or NULL */ 1401 Oid infercollid; /* OID of collation, or InvalidOid */ 1402 Oid inferopclass; /* OID of att opclass, or InvalidOid */ 1403 } InferenceElem; 1404 1405 /*-------------------- 1406 * TargetEntry - 1407 * a target entry (used in query target lists) 1408 * 1409 * Strictly speaking, a TargetEntry isn't an expression node (since it can't 1410 * be evaluated by ExecEvalExpr). But we treat it as one anyway, since in 1411 * very many places it's convenient to process a whole query targetlist as a 1412 * single expression tree. 1413 * 1414 * In a SELECT's targetlist, resno should always be equal to the item's 1415 * ordinal position (counting from 1). However, in an INSERT or UPDATE 1416 * targetlist, resno represents the attribute number of the destination 1417 * column for the item; so there may be missing or out-of-order resnos. 1418 * It is even legal to have duplicated resnos; consider 1419 * UPDATE table SET arraycol[1] = ..., arraycol[2] = ..., ... 1420 * In an INSERT, the rewriter and planner will normalize the tlist by 1421 * reordering it into physical column order and filling in default values 1422 * for any columns not assigned values by the original query. In an UPDATE, 1423 * after the rewriter merges multiple assignments for the same column, the 1424 * planner extracts the target-column numbers into a separate "update_colnos" 1425 * list, and then renumbers the tlist elements serially. Thus, tlist resnos 1426 * match ordinal position in all tlists seen by the executor; but it is wrong 1427 * to assume that before planning has happened. 1428 * 1429 * resname is required to represent the correct column name in non-resjunk 1430 * entries of top-level SELECT targetlists, since it will be used as the 1431 * column title sent to the frontend. In most other contexts it is only 1432 * a debugging aid, and may be wrong or even NULL. (In particular, it may 1433 * be wrong in a tlist from a stored rule, if the referenced column has been 1434 * renamed by ALTER TABLE since the rule was made. Also, the planner tends 1435 * to store NULL rather than look up a valid name for tlist entries in 1436 * non-toplevel plan nodes.) In resjunk entries, resname should be either 1437 * a specific system-generated name (such as "ctid") or NULL; anything else 1438 * risks confusing ExecGetJunkAttribute! 1439 * 1440 * ressortgroupref is used in the representation of ORDER BY, GROUP BY, and 1441 * DISTINCT items. Targetlist entries with ressortgroupref=0 are not 1442 * sort/group items. If ressortgroupref>0, then this item is an ORDER BY, 1443 * GROUP BY, and/or DISTINCT target value. No two entries in a targetlist 1444 * may have the same nonzero ressortgroupref --- but there is no particular 1445 * meaning to the nonzero values, except as tags. (For example, one must 1446 * not assume that lower ressortgroupref means a more significant sort key.) 1447 * The order of the associated SortGroupClause lists determine the semantics. 1448 * 1449 * resorigtbl/resorigcol identify the source of the column, if it is a 1450 * simple reference to a column of a base table (or view). If it is not 1451 * a simple reference, these fields are zeroes. 1452 * 1453 * If resjunk is true then the column is a working column (such as a sort key) 1454 * that should be removed from the final output of the query. Resjunk columns 1455 * must have resnos that cannot duplicate any regular column's resno. Also 1456 * note that there are places that assume resjunk columns come after non-junk 1457 * columns. 1458 *-------------------- 1459 */ 1460 typedef struct TargetEntry 1461 { 1462 Expr xpr; 1463 Expr *expr; /* expression to evaluate */ 1464 AttrNumber resno; /* attribute number (see notes above) */ 1465 char *resname; /* name of the column (could be NULL) */ 1466 Index ressortgroupref; /* nonzero if referenced by a sort/group 1467 * clause */ 1468 Oid resorigtbl; /* OID of column's source table */ 1469 AttrNumber resorigcol; /* column's number in source table */ 1470 bool resjunk; /* set to true to eliminate the attribute from 1471 * final target list */ 1472 } TargetEntry; 1473 1474 1475 /* ---------------------------------------------------------------- 1476 * node types for join trees 1477 * 1478 * The leaves of a join tree structure are RangeTblRef nodes. Above 1479 * these, JoinExpr nodes can appear to denote a specific kind of join 1480 * or qualified join. Also, FromExpr nodes can appear to denote an 1481 * ordinary cross-product join ("FROM foo, bar, baz WHERE ..."). 1482 * FromExpr is like a JoinExpr of jointype JOIN_INNER, except that it 1483 * may have any number of child nodes, not just two. 1484 * 1485 * NOTE: the top level of a Query's jointree is always a FromExpr. 1486 * Even if the jointree contains no rels, there will be a FromExpr. 1487 * 1488 * NOTE: the qualification expressions present in JoinExpr nodes are 1489 * *in addition to* the query's main WHERE clause, which appears as the 1490 * qual of the top-level FromExpr. The reason for associating quals with 1491 * specific nodes in the jointree is that the position of a qual is critical 1492 * when outer joins are present. (If we enforce a qual too soon or too late, 1493 * that may cause the outer join to produce the wrong set of NULL-extended 1494 * rows.) If all joins are inner joins then all the qual positions are 1495 * semantically interchangeable. 1496 * 1497 * NOTE: in the raw output of gram.y, a join tree contains RangeVar, 1498 * RangeSubselect, and RangeFunction nodes, which are all replaced by 1499 * RangeTblRef nodes during the parse analysis phase. Also, the top-level 1500 * FromExpr is added during parse analysis; the grammar regards FROM and 1501 * WHERE as separate. 1502 * ---------------------------------------------------------------- 1503 */ 1504 1505 /* 1506 * RangeTblRef - reference to an entry in the query's rangetable 1507 * 1508 * We could use direct pointers to the RT entries and skip having these 1509 * nodes, but multiple pointers to the same node in a querytree cause 1510 * lots of headaches, so it seems better to store an index into the RT. 1511 */ 1512 typedef struct RangeTblRef 1513 { 1514 NodeTag type; 1515 int rtindex; 1516 } RangeTblRef; 1517 1518 /*---------- 1519 * JoinExpr - for SQL JOIN expressions 1520 * 1521 * isNatural, usingClause, and quals are interdependent. The user can write 1522 * only one of NATURAL, USING(), or ON() (this is enforced by the grammar). 1523 * If he writes NATURAL then parse analysis generates the equivalent USING() 1524 * list, and from that fills in "quals" with the right equality comparisons. 1525 * If he writes USING() then "quals" is filled with equality comparisons. 1526 * If he writes ON() then only "quals" is set. Note that NATURAL/USING 1527 * are not equivalent to ON() since they also affect the output column list. 1528 * 1529 * alias is an Alias node representing the AS alias-clause attached to the 1530 * join expression, or NULL if no clause. NB: presence or absence of the 1531 * alias has a critical impact on semantics, because a join with an alias 1532 * restricts visibility of the tables/columns inside it. 1533 * 1534 * join_using_alias is an Alias node representing the join correlation 1535 * name that SQL:2016 and later allow to be attached to JOIN/USING. 1536 * Its column alias list includes only the common column names from USING, 1537 * and it does not restrict visibility of the join's input tables. 1538 * 1539 * During parse analysis, an RTE is created for the Join, and its index 1540 * is filled into rtindex. This RTE is present mainly so that Vars can 1541 * be created that refer to the outputs of the join. The planner sometimes 1542 * generates JoinExprs internally; these can have rtindex = 0 if there are 1543 * no join alias variables referencing such joins. 1544 *---------- 1545 */ 1546 typedef struct JoinExpr 1547 { 1548 NodeTag type; 1549 JoinType jointype; /* type of join */ 1550 bool isNatural; /* Natural join? Will need to shape table */ 1551 Node *larg; /* left subtree */ 1552 Node *rarg; /* right subtree */ 1553 List *usingClause; /* USING clause, if any (list of String) */ 1554 Alias *join_using_alias; /* alias attached to USING clause, if any */ 1555 Node *quals; /* qualifiers on join, if any */ 1556 Alias *alias; /* user-written alias clause, if any */ 1557 int rtindex; /* RT index assigned for join, or 0 */ 1558 } JoinExpr; 1559 1560 /*---------- 1561 * FromExpr - represents a FROM ... WHERE ... construct 1562 * 1563 * This is both more flexible than a JoinExpr (it can have any number of 1564 * children, including zero) and less so --- we don't need to deal with 1565 * aliases and so on. The output column set is implicitly just the union 1566 * of the outputs of the children. 1567 *---------- 1568 */ 1569 typedef struct FromExpr 1570 { 1571 NodeTag type; 1572 List *fromlist; /* List of join subtrees */ 1573 Node *quals; /* qualifiers on join, if any */ 1574 } FromExpr; 1575 1576 /*---------- 1577 * OnConflictExpr - represents an ON CONFLICT DO ... expression 1578 * 1579 * The optimizer requires a list of inference elements, and optionally a WHERE 1580 * clause to infer a unique index. The unique index (or, occasionally, 1581 * indexes) inferred are used to arbitrate whether or not the alternative ON 1582 * CONFLICT path is taken. 1583 *---------- 1584 */ 1585 typedef struct OnConflictExpr 1586 { 1587 NodeTag type; 1588 OnConflictAction action; /* DO NOTHING or UPDATE? */ 1589 1590 /* Arbiter */ 1591 List *arbiterElems; /* unique index arbiter list (of 1592 * InferenceElem's) */ 1593 Node *arbiterWhere; /* unique index arbiter WHERE clause */ 1594 Oid constraint; /* pg_constraint OID for arbiter */ 1595 1596 /* ON CONFLICT UPDATE */ 1597 List *onConflictSet; /* List of ON CONFLICT SET TargetEntry nodes */ 1598 Node *onConflictWhere; /* qualifiers to restrict UPDATE to */ 1599 int exclRelIndex; /* RT index of 'excluded' relation */ 1600 List *exclRelTlist; /* tlist of the EXCLUDED pseudo relation */ 1601 } OnConflictExpr; 1602 1603 #endif /* PRIMNODES_H */ 1604