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