/*------------------------------------------------------------------------- * * primnodes.h * Definitions for "primitive" node types, those that are used in more * than one of the parse/plan/execute stages of the query pipeline. * Currently, these are mostly nodes for executable expressions * and join trees. * * * Portions Copyright (c) 1996-2017, PostgreSQL Global Development PGGroup * Portions Copyright (c) 1994, Regents of the University of California * * src/include/nodes/primnodes.h * *------------------------------------------------------------------------- */ #pragma once #include "access/attnum.hpp" #include "nodes/bitmapset.hpp" #include "nodes/pg_list.hpp" namespace duckdb_libpgquery { /* ---------------------------------------------------------------- * node definitions * ---------------------------------------------------------------- */ /* * PGAlias - * specifies an alias for a range variable; the alias might also * specify renaming of columns within the table. * * Note: colnames is a list of PGValue nodes (always strings). In PGAlias structs * associated with RTEs, there may be entries corresponding to dropped * columns; these are normally empty strings (""). See parsenodes.h for info. */ typedef struct PGAlias { PGNodeTag type; char *aliasname; /* aliased rel name (never qualified) */ PGList *colnames; /* optional list of column aliases */ } PGAlias; /* What to do at commit time for temporary relations */ typedef enum PGOnCommitAction { PG_ONCOMMIT_NOOP, /* No ON COMMIT clause (do nothing) */ PG_ONCOMMIT_PRESERVE_ROWS, /* ON COMMIT PRESERVE ROWS (do nothing) */ PG_ONCOMMIT_DELETE_ROWS, /* ON COMMIT DELETE ROWS */ ONCOMMIT_DROP /* ON COMMIT DROP */ } PGOnCommitAction; /* What to do at commit time for temporary relations */ typedef enum PGOnCreateConflict { // Standard: throw error PG_ERROR_ON_CONFLICT, // CREATE IF NOT EXISTS, silently do nothing on conflict PG_IGNORE_ON_CONFLICT, // CREATE OR REPLACE PG_REPLACE_ON_CONFLICT } PGOnCreateConflict; /* * PGRangeVar - range variable, used in FROM clauses * * Also used to represent table names in utility statements; there, the alias * field is not used, and inh tells whether to apply the operation * recursively to child tables. In some contexts it is also useful to carry * a TEMP table indication here. */ typedef struct PGRangeVar { PGNodeTag type; char *catalogname; /* the catalog (database) name, or NULL */ char *schemaname; /* the schema name, or NULL */ char *relname; /* the relation/sequence name */ bool inh; /* expand rel by inheritance? recursively act * on children? */ char relpersistence; /* see RELPERSISTENCE_* in pg_class.h */ PGNode *at_clause; /* version of the table to read */ PGAlias *alias; /* table alias & optional column aliases */ int location; /* token location, or -1 if unknown */ PGNode *sample; /* sample, if any */ } PGRangeVar; /* * PGTableFunc - node for a table function, such as XMLTABLE. */ typedef struct PGTableFunc { PGNodeTag type; PGList *ns_uris; /* list of namespace uri */ PGList *ns_names; /* list of namespace names */ PGNode *docexpr; /* input document expression */ PGNode *rowexpr; /* row filter expression */ PGList *colnames; /* column names (list of String) */ PGList *coltypes; /* OID list of column type OIDs */ PGList *coltypmods; /* integer list of column typmods */ PGList *colcollations; /* OID list of column collation OIDs */ PGList *colexprs; /* list of column filter expressions */ PGList *coldefexprs; /* list of column default expressions */ PGBitmapset *notnulls; /* nullability flag for each output column */ int ordinalitycol; /* counts from 0; -1 if none specified */ int location; /* token location, or -1 if unknown */ } PGTableFunc; /* * PGIntoClause - target information for SELECT INTO, CREATE TABLE AS, and * CREATE MATERIALIZED VIEW * * For CREATE MATERIALIZED VIEW, viewQuery is the parsed-but-not-rewritten * SELECT PGQuery for the view; otherwise it's NULL. (Although it's actually * PGQuery*, we declare it as PGNode* to avoid a forward reference.) */ typedef struct PGIntoClause { PGNodeTag type; PGRangeVar *rel; /* target relation name */ PGList *colNames; /* column names to assign, or NIL */ PGList *options; /* options from WITH clause */ PGOnCommitAction onCommit; /* what do we do at COMMIT? */ char *tableSpaceName; /* table space to use, or NULL */ PGNode *viewQuery; /* materialized view's SELECT query */ bool skipData; /* true for WITH NO DATA */ } PGIntoClause; /* ---------------------------------------------------------------- * node types for executable expressions * ---------------------------------------------------------------- */ /* * PGExpr - generic superclass for executable-expression nodes * * All node types that are used in executable expression trees should derive * from PGExpr (that is, have PGExpr as their first field). Since PGExpr only * contains PGNodeTag, this is a formality, but it is an easy form of * documentation. See also the ExprState node types in execnodes.h. */ typedef struct PGExpr { PGNodeTag type; } PGExpr; /* * PGVar - expression node representing a variable (ie, a table column) * * Note: during parsing/planning, varnoold/varoattno are always just copies * of varno/varattno. At the tail end of planning, PGVar nodes appearing in * upper-level plan nodes are reassigned to point to the outputs of their * subplans; for example, in a join node varno becomes INNER_VAR or OUTER_VAR * and varattno becomes the index of the proper element of that subplan's * target list. Similarly, INDEX_VAR is used to identify Vars that reference * an index column rather than a heap column. (In PGForeignScan and PGCustomScan * plan nodes, INDEX_VAR is abused to signify references to columns of a * custom scan tuple type.) In all these cases, varnoold/varoattno hold the * original values. The code doesn't really need varnoold/varoattno, but they * are very useful for debugging and interpreting completed plans, so we keep * them around. */ #define INNER_VAR 65000 /* reference to inner subplan */ #define OUTER_VAR 65001 /* reference to outer subplan */ #define INDEX_VAR 65002 /* reference to index column */ #define IS_SPECIAL_VARNO(varno) ((varno) >= INNER_VAR) /* Symbols for the indexes of the special RTE entries in rules */ #define PRS2_OLD_VARNO 1 #define PRS2_NEW_VARNO 2 typedef struct PGVar { PGExpr xpr; PGIndex varno; /* index of this var's relation in the range * table, or INNER_VAR/OUTER_VAR/INDEX_VAR */ PGAttrNumber varattno; /* attribute number of this var, or zero for * all */ PGOid vartype; /* pg_type OID for the type of this var */ int32_t vartypmod; /* pg_attribute typmod value */ PGOid varcollid; /* OID of collation, or InvalidOid if none */ PGIndex varlevelsup; /* for subquery variables referencing outer * relations; 0 in a normal var, >0 means N * levels up */ PGIndex varnoold; /* original value of varno, for debugging */ PGAttrNumber varoattno; /* original value of varattno */ int location; /* token location, or -1 if unknown */ } PGVar; /* * PGConst * * Note: for pg_varlena data types, we make a rule that a PGConst node's value * must be in non-extended form (4-byte header, no compression or external * references). This ensures that the PGConst node is self-contained and makes * it more likely that equal() will see logically identical values as equal. */ typedef struct PGConst { PGExpr xpr; PGOid consttype; /* pg_type OID of the constant's datatype */ int32_t consttypmod; /* typmod value, if any */ PGOid constcollid; /* OID of collation, or InvalidOid if none */ int constlen; /* typlen of the constant's datatype */ PGDatum constvalue; /* the constant's value */ bool constisnull; /* whether the constant is null (if true, * constvalue is undefined) */ bool constbyval; /* whether this datatype is passed by value. * If true, then all the information is stored * in the Datum. If false, then the PGDatum * contains a pointer to the information. */ int location; /* token location, or -1 if unknown */ } PGConst; /* * PGParam * * paramkind specifies the kind of parameter. The possible values * for this field are: * * PG_PARAM_EXTERN: The parameter value is supplied from outside the plan. * Such parameters are numbered from 1 to n. * * PG_PARAM_EXEC: The parameter is an internal executor parameter, used * for passing values into and out of sub-queries or from * nestloop joins to their inner scans. * For historical reasons, such parameters are numbered from 0. * These numbers are independent of PG_PARAM_EXTERN numbers. * * PG_PARAM_SUBLINK: The parameter represents an output column of a PGSubLink * node's sub-select. The column number is contained in the * `paramid' field. (This type of PGParam is converted to * PG_PARAM_EXEC during planning.) * * PG_PARAM_MULTIEXPR: Like PG_PARAM_SUBLINK, the parameter represents an * output column of a PGSubLink node's sub-select, but here, the * PGSubLink is always a MULTIEXPR SubLink. The high-order 16 bits * of the `paramid' field contain the SubLink's subLinkId, and * the low-order 16 bits contain the column number. (This type * of PGParam is also converted to PG_PARAM_EXEC during planning.) */ typedef enum PGParamKind { PG_PARAM_EXTERN, PG_PARAM_EXEC, PG_PARAM_SUBLINK, PG_PARAM_MULTIEXPR } PGParamKind; typedef struct PGParam { PGExpr xpr; PGParamKind paramkind; /* kind of parameter. See above */ int paramid; /* numeric ID for parameter */ PGOid paramtype; /* pg_type OID of parameter's datatype */ int32_t paramtypmod; /* typmod value, if known */ PGOid paramcollid; /* OID of collation, or InvalidOid if none */ int location; /* token location, or -1 if unknown */ } PGParam; /* * PGAggref * * The aggregate's args list is a targetlist, ie, a list of PGTargetEntry nodes. * * For a normal (non-ordered-set) aggregate, the non-resjunk TargetEntries * represent the aggregate's regular arguments (if any) and resjunk TLEs can * be added at the end to represent ORDER BY expressions that are not also * arguments. As in a top-level PGQuery, the TLEs can be marked with * ressortgroupref indexes to let them be referenced by PGSortGroupClause * entries in the aggorder and/or aggdistinct lists. This represents ORDER BY * and DISTINCT operations to be applied to the aggregate input rows before * they are passed to the transition function. The grammar only allows a * simple "DISTINCT" specifier for the arguments, but we use the full * query-level representation to allow more code sharing. * * For an ordered-set aggregate, the args list represents the WITHIN GROUP * (aggregated) arguments, all of which will be listed in the aggorder list. * DISTINCT is not supported in this case, so aggdistinct will be NIL. * The direct arguments appear in aggdirectargs (as a list of plain * expressions, not PGTargetEntry nodes). * * aggtranstype is the data type of the state transition values for this * aggregate (resolved to an actual type, if agg's transtype is polymorphic). * This is determined during planning and is InvalidOid before that. * * aggargtypes is an OID list of the data types of the direct and regular * arguments. Normally it's redundant with the aggdirectargs and args lists, * but in a combining aggregate, it's not because the args list has been * replaced with a single argument representing the partial-aggregate * transition values. * * aggsplit indicates the expected partial-aggregation mode for the Aggref's * parent plan node. It's always set to PG_AGGSPLIT_SIMPLE in the parser, but * the planner might change it to something else. We use this mainly as * a crosscheck that the Aggrefs match the plan; but note that when aggsplit * indicates a non-final mode, aggtype reflects the transition data type * not the SQL-level output type of the aggregate. */ typedef struct PGAggref { PGExpr xpr; PGOid aggfnoid; /* pg_proc PGOid of the aggregate */ PGOid aggtype; /* type PGOid of result of the aggregate */ PGOid aggcollid; /* OID of collation of result */ PGOid inputcollid; /* OID of collation that function should use */ PGOid aggtranstype; /* type PGOid of aggregate's transition value */ PGList *aggargtypes; /* type Oids of direct and aggregated args */ PGList *aggdirectargs; /* direct arguments, if an ordered-set agg */ PGList *args; /* aggregated arguments and sort expressions */ PGList *aggorder; /* ORDER BY (list of PGSortGroupClause) */ PGList *aggdistinct; /* DISTINCT (list of PGSortGroupClause) */ PGExpr *aggfilter; /* FILTER expression, if any */ bool aggstar; /* true if argument list was really '*' */ bool aggvariadic; /* true if variadic arguments have been * combined into an array last argument */ char aggkind; /* aggregate kind (see pg_aggregate.h) */ PGIndex agglevelsup; /* > 0 if agg belongs to outer query */ PGAggSplit aggsplit; /* expected agg-splitting mode of parent PGAgg */ int location; /* token location, or -1 if unknown */ } PGAggref; /* * PGGroupingFunc * * A PGGroupingFunc is a GROUPING(...) expression, which behaves in many ways * like an aggregate function (e.g. it "belongs" to a specific query level, * which might not be the one immediately containing it), but also differs in * an important respect: it never evaluates its arguments, they merely * designate expressions from the GROUP BY clause of the query level to which * it belongs. * * The spec defines the evaluation of GROUPING() purely by syntactic * replacement, but we make it a real expression for optimization purposes so * that one PGAgg node can handle multiple grouping sets at once. Evaluating the * result only needs the column positions to check against the grouping set * being projected. However, for EXPLAIN to produce meaningful output, we have * to keep the original expressions around, since expression deparse does not * give us any feasible way to get at the GROUP BY clause. * * Also, we treat two PGGroupingFunc nodes as equal if they have equal arguments * lists and agglevelsup, without comparing the refs and cols annotations. * * In raw parse output we have only the args list; parse analysis fills in the * refs list, and the planner fills in the cols list. */ typedef struct PGGroupingFunc { PGExpr xpr; PGList *args; /* arguments, not evaluated but kept for * benefit of EXPLAIN etc. */ PGList *refs; /* ressortgrouprefs of arguments */ PGList *cols; /* actual column positions set by planner */ PGIndex agglevelsup; /* same as Aggref.agglevelsup */ int location; /* token location */ } PGGroupingFunc; /* * PGWindowFunc */ typedef struct PGWindowFunc { PGExpr xpr; PGOid winfnoid; /* pg_proc PGOid of the function */ PGOid wintype; /* type PGOid of result of the window function */ PGOid wincollid; /* OID of collation of result */ PGOid inputcollid; /* OID of collation that function should use */ PGList *args; /* arguments to the window function */ PGExpr *aggfilter; /* FILTER expression, if any */ PGIndex winref; /* index of associated PGWindowClause */ bool winstar; /* true if argument list was really '*' */ bool winagg; /* is function a simple aggregate? */ int location; /* token location, or -1 if unknown */ } PGWindowFunc; /* ---------------- * PGArrayRef: describes an array subscripting operation * * An PGArrayRef can describe fetching a single element from an array, * fetching a subarray (array slice), storing a single element into * an array, or storing a slice. The "store" cases work with an * initial array value and a source value that is inserted into the * appropriate part of the array; the result of the operation is an * entire new modified array value. * * If reflowerindexpr = NIL, then we are fetching or storing a single array * element at the subscripts given by refupperindexpr. Otherwise we are * fetching or storing an array slice, that is a rectangular subarray * with lower and upper bounds given by the index expressions. * reflowerindexpr must be the same length as refupperindexpr when it * is not NIL. * * In the slice case, individual expressions in the subscript lists can be * NULL, meaning "substitute the array's current lower or upper bound". * * Note: the result datatype is the element type when fetching a single * element; but it is the array type when doing subarray fetch or either * type of store. * * Note: for the cases where an array is returned, if refexpr yields a R/W * expanded array, then the implementation is allowed to modify that object * in-place and return the same object.) * ---------------- */ typedef struct PGArrayRef { PGExpr xpr; PGOid refarraytype; /* type of the array proper */ PGOid refelemtype; /* type of the array elements */ int32_t reftypmod; /* typmod of the array (and elements too) */ PGOid refcollid; /* OID of collation, or InvalidOid if none */ PGList *refupperindexpr; /* expressions that evaluate to upper * array indexes */ PGList *reflowerindexpr; /* expressions that evaluate to lower * array indexes, or NIL for single array * element */ PGExpr *refexpr; /* the expression that evaluates to an array * value */ PGExpr *refassgnexpr; /* expression for the source value, or NULL if * fetch */ } PGArrayRef; /* * PGCoercionContext - distinguishes the allowed set of type casts * * NB: ordering of the alternatives is significant; later (larger) values * allow more casts than earlier ones. */ typedef enum PGCoercionContext { PG_COERCION_IMPLICIT, /* coercion in context of expression */ PG_COERCION_ASSIGNMENT, /* coercion in context of assignment */ PG_COERCION_EXPLICIT /* explicit cast operation */ } PGCoercionContext; /* * PGCoercionForm - how to display a node that could have come from a cast * * NB: equal() ignores PGCoercionForm fields, therefore this *must* not carry * any semantically significant information. We need that behavior so that * the planner will consider equivalent implicit and explicit casts to be * equivalent. In cases where those actually behave differently, the coercion * function's arguments will be different. */ typedef enum PGCoercionForm { PG_COERCE_EXPLICIT_CALL, /* display as a function call */ PG_COERCE_EXPLICIT_CAST, /* display as an explicit cast */ PG_COERCE_IMPLICIT_CAST /* implicit cast, so hide it */ } PGCoercionForm; /* * PGFuncExpr - expression node for a function call */ typedef struct PGFuncExpr { PGExpr xpr; PGOid funcid; /* PG_PROC OID of the function */ PGOid funcresulttype; /* PG_TYPE OID of result value */ bool funcretset; /* true if function returns set */ bool funcvariadic; /* true if variadic arguments have been * combined into an array last argument */ PGCoercionForm funcformat; /* how to display this function call */ PGOid funccollid; /* OID of collation of result */ PGOid inputcollid; /* OID of collation that function should use */ PGList *args; /* arguments to the function */ int location; /* token location, or -1 if unknown */ } PGFuncExpr; /* * PGNamedArgExpr - a named argument of a function * * This node type can only appear in the args list of a PGFuncCall or PGFuncExpr * node. We support pure positional call notation (no named arguments), * named notation (all arguments are named), and mixed notation (unnamed * arguments followed by named ones). * * Parse analysis sets argnumber to the positional index of the argument, * but doesn't rearrange the argument list. * * The planner will convert argument lists to pure positional notation * during expression preprocessing, so execution never sees a NamedArgExpr. */ typedef struct PGNamedArgExpr { PGExpr xpr; PGExpr *arg; /* the argument expression */ char *name; /* the name */ int argnumber; /* argument's number in positional notation */ int location; /* argument name location, or -1 if unknown */ } PGNamedArgExpr; /* * PGOpExpr - expression node for an operator invocation * * Semantically, this is essentially the same as a function call. * * Note that opfuncid is not necessarily filled in immediately on creation * of the node. The planner makes sure it is valid before passing the node * tree to the executor, but during parsing/planning opfuncid can be 0. */ typedef struct PGOpExpr { PGExpr xpr; PGOid opno; /* PG_OPERATOR OID of the operator */ PGOid opfuncid; /* PG_PROC OID of underlying function */ PGOid opresulttype; /* PG_TYPE OID of result value */ bool opretset; /* true if operator returns set */ PGOid opcollid; /* OID of collation of result */ PGOid inputcollid; /* OID of collation that operator should use */ PGList *args; /* arguments to the operator (1 or 2) */ int location; /* token location, or -1 if unknown */ } PGOpExpr; /* * DistinctExpr - expression node for "x IS DISTINCT FROM y" * * Except for the nodetag, this is represented identically to an PGOpExpr * referencing the "=" operator for x and y. * We use "=", not the more obvious "<>", because more datatypes have "=" * than "<>". This means the executor must invert the operator result. * Note that the operator function won't be called at all if either input * is NULL, since then the result can be determined directly. */ typedef PGOpExpr DistinctExpr; /* * NullIfExpr - a NULLIF expression * * Like DistinctExpr, this is represented the same as an PGOpExpr referencing * the "=" operator for x and y. */ typedef PGOpExpr NullIfExpr; /* * PGScalarArrayOpExpr - expression node for "scalar op ANY/ALL (array)" * * The operator must yield boolean. It is applied to the left operand * and each element of the righthand array, and the results are combined * with OR or AND (for ANY or ALL respectively). The node representation * is almost the same as for the underlying operator, but we need a useOr * flag to remember whether it's ANY or ALL, and we don't have to store * the result type (or the collation) because it must be boolean. */ typedef struct PGScalarArrayOpExpr { PGExpr xpr; PGOid opno; /* PG_OPERATOR OID of the operator */ PGOid opfuncid; /* PG_PROC OID of underlying function */ bool useOr; /* true for ANY, false for ALL */ PGOid inputcollid; /* OID of collation that operator should use */ PGList *args; /* the scalar and array operands */ int location; /* token location, or -1 if unknown */ } PGScalarArrayOpExpr; /* * PGBoolExpr - expression node for the basic Boolean operators AND, OR, NOT * * Notice the arguments are given as a List. For NOT, of course the list * must always have exactly one element. For AND and OR, there can be two * or more arguments. */ typedef enum PGBoolExprType { PG_AND_EXPR, PG_OR_EXPR, PG_NOT_EXPR } PGBoolExprType; typedef struct PGBoolExpr { PGExpr xpr; PGBoolExprType boolop; PGList *args; /* arguments to this expression */ int location; /* token location, or -1 if unknown */ } PGBoolExpr; /* * PGSubLink * * A PGSubLink represents a subselect appearing in an expression, and in some * cases also the combining operator(s) just above it. The subLinkType * indicates the form of the expression represented: * PG_EXISTS_SUBLINK EXISTS(SELECT ...) * PG_ALL_SUBLINK (lefthand) op ALL (SELECT ...) * PG_ANY_SUBLINK (lefthand) op ANY (SELECT ...) * PG_ROWCOMPARE_SUBLINK (lefthand) op (SELECT ...) * PG_EXPR_SUBLINK (SELECT with single targetlist item ...) * PG_MULTIEXPR_SUBLINK (SELECT with multiple targetlist items ...) * PG_ARRAY_SUBLINK ARRAY(SELECT with single targetlist item ...) * PG_CTE_SUBLINK WITH query (never actually part of an expression) * For ALL, ANY, and ROWCOMPARE, the lefthand is a list of expressions of the * same length as the subselect's targetlist. ROWCOMPARE will *always* have * a list with more than one entry; if the subselect has just one target * then the parser will create an PG_EXPR_SUBLINK instead (and any operator * above the subselect will be represented separately). * ROWCOMPARE, EXPR, and MULTIEXPR require the subselect to deliver at most * one row (if it returns no rows, the result is NULL). * ALL, ANY, and ROWCOMPARE require the combining operators to deliver boolean * results. ALL and ANY combine the per-row results using AND and OR * semantics respectively. * ARRAY requires just one target column, and creates an array of the target * column's type using any number of rows resulting from the subselect. * * PGSubLink is classed as an PGExpr node, but it is not actually executable; * it must be replaced in the expression tree by a PGSubPlan node during * planning. * * NOTE: in the raw output of gram.y, testexpr contains just the raw form * of the lefthand expression (if any), and operName is the String name of * the combining operator. Also, subselect is a raw parsetree. During parse * analysis, the parser transforms testexpr into a complete boolean expression * that compares the lefthand value(s) to PG_PARAM_SUBLINK nodes representing the * output columns of the subselect. And subselect is transformed to a Query. * This is the representation seen in saved rules and in the rewriter. * * In EXISTS, EXPR, MULTIEXPR, and ARRAY SubLinks, testexpr and operName * are unused and are always null. * * subLinkId is currently used only for MULTIEXPR SubLinks, and is zero in * other SubLinks. This number identifies different multiple-assignment * subqueries within an UPDATE statement's SET list. It is unique only * within a particular targetlist. The output column(s) of the MULTIEXPR * are referenced by PG_PARAM_MULTIEXPR Params appearing elsewhere in the tlist. * * The PG_CTE_SUBLINK case never occurs in actual PGSubLink nodes, but it is used * in SubPlans generated for WITH subqueries. */ typedef enum PGSubLinkType { PG_EXISTS_SUBLINK, PG_ALL_SUBLINK, PG_ANY_SUBLINK, PG_ROWCOMPARE_SUBLINK, PG_EXPR_SUBLINK, PG_MULTIEXPR_SUBLINK, PG_ARRAY_SUBLINK, PG_CTE_SUBLINK /* for SubPlans only */ } PGSubLinkType; typedef struct PGSubLink { PGExpr xpr; PGSubLinkType subLinkType; /* see above */ int subLinkId; /* ID (1..n); 0 if not MULTIEXPR */ PGNode *testexpr; /* outer-query test for ALL/ANY/ROWCOMPARE */ PGList *operName; /* originally specified operator name */ PGNode *subselect; /* subselect as PGQuery* or raw parsetree */ int location; /* token location, or -1 if unknown */ } PGSubLink; /* * PGSubPlan - executable expression node for a subplan (sub-SELECT) * * The planner replaces PGSubLink nodes in expression trees with PGSubPlan * nodes after it has finished planning the subquery. PGSubPlan references * a sub-plantree stored in the subplans list of the toplevel PlannedStmt. * (We avoid a direct link to make it easier to copy expression trees * without causing multiple processing of the subplan.) * * In an ordinary subplan, testexpr points to an executable expression * (PGOpExpr, an AND/OR tree of OpExprs, or PGRowCompareExpr) for the combining * operator(s); the left-hand arguments are the original lefthand expressions, * and the right-hand arguments are PG_PARAM_EXEC PGParam nodes representing the * outputs of the sub-select. (NOTE: runtime coercion functions may be * inserted as well.) This is just the same expression tree as testexpr in * the original PGSubLink node, but the PG_PARAM_SUBLINK nodes are replaced by * suitably numbered PG_PARAM_EXEC nodes. * * If the sub-select becomes an initplan rather than a subplan, the executable * expression is part of the outer plan's expression tree (and the PGSubPlan * node itself is not, but rather is found in the outer plan's initPlan * list). In this case testexpr is NULL to avoid duplication. * * The planner also derives lists of the values that need to be passed into * and out of the subplan. Input values are represented as a list "args" of * expressions to be evaluated in the outer-query context (currently these * args are always just Vars, but in principle they could be any expression). * The values are assigned to the global PG_PARAM_EXEC params indexed by parParam * (the parParam and args lists must have the same ordering). setParam is a * list of the PG_PARAM_EXEC params that are computed by the sub-select, if it * is an initplan; they are listed in order by sub-select output column * position. (parParam and setParam are integer Lists, not Bitmapsets, * because their ordering is significant.) * * Also, the planner computes startup and per-call costs for use of the * SubPlan. Note that these include the cost of the subquery proper, * evaluation of the testexpr if any, and any hashtable management overhead. */ typedef struct PGSubPlan { PGExpr xpr; /* Fields copied from original PGSubLink: */ PGSubLinkType subLinkType; /* see above */ /* The combining operators, transformed to an executable expression: */ PGNode *testexpr; /* PGOpExpr or PGRowCompareExpr expression tree */ PGList *paramIds; /* IDs of Params embedded in the above */ /* Identification of the PGPlan tree to use: */ int plan_id; /* PGIndex (from 1) in PlannedStmt.subplans */ /* Identification of the PGSubPlan for EXPLAIN and debugging purposes: */ char *plan_name; /* A name assigned during planning */ /* Extra data useful for determining subplan's output type: */ PGOid firstColType; /* Type of first column of subplan result */ int32_t firstColTypmod; /* Typmod of first column of subplan result */ PGOid firstColCollation; /* Collation of first column of subplan * result */ /* Information about execution strategy: */ bool useHashTable; /* true to store subselect output in a hash * table (implies we are doing "IN") */ bool unknownEqFalse; /* true if it's okay to return false when the * spec result is UNKNOWN; this allows much * simpler handling of null values */ bool parallel_safe; /* is the subplan parallel-safe? */ /* Note: parallel_safe does not consider contents of testexpr or args */ /* Information for passing params into and out of the subselect: */ /* setParam and parParam are lists of integers (param IDs) */ PGList *setParam; /* initplan subqueries have to set these * Params for parent plan */ PGList *parParam; /* indices of input Params from parent plan */ PGList *args; /* exprs to pass as parParam values */ /* Estimated execution costs: */ Cost startup_cost; /* one-time setup cost */ Cost per_call_cost; /* cost for each subplan evaluation */ } PGSubPlan; /* * PGAlternativeSubPlan - expression node for a choice among SubPlans * * The subplans are given as a PGList so that the node definition need not * change if there's ever more than two alternatives. For the moment, * though, there are always exactly two; and the first one is the fast-start * plan. */ typedef struct PGAlternativeSubPlan { PGExpr xpr; PGList *subplans; /* SubPlan(s) with equivalent results */ } PGAlternativeSubPlan; /* ---------------- * PGFieldSelect * * PGFieldSelect represents the operation of extracting one field from a tuple * value. At runtime, the input expression is expected to yield a rowtype * Datum. The specified field number is extracted and returned as a Datum. * ---------------- */ typedef struct PGFieldSelect { PGExpr xpr; PGExpr *arg; /* input expression */ PGAttrNumber fieldnum; /* attribute number of field to extract */ PGOid resulttype; /* type of the field (result type of this * node) */ int32_t resulttypmod; /* output typmod (usually -1) */ PGOid resultcollid; /* OID of collation of the field */ } PGFieldSelect; /* ---------------- * PGFieldStore * * PGFieldStore represents the operation of modifying one field in a tuple * value, yielding a new tuple value (the input is not touched!). Like * the assign case of PGArrayRef, this is used to implement UPDATE of a * portion of a column. * * A single PGFieldStore can actually represent updates of several different * fields. The parser only generates FieldStores with single-element lists, * but the planner will collapse multiple updates of the same base column * into one FieldStore. * ---------------- */ typedef struct PGFieldStore { PGExpr xpr; PGExpr *arg; /* input tuple value */ PGList *newvals; /* new value(s) for field(s) */ PGList *fieldnums; /* integer list of field attnums */ PGOid resulttype; /* type of result (same as type of arg) */ /* Like PGRowExpr, we deliberately omit a typmod and collation here */ } PGFieldStore; /* ---------------- * PGRelabelType * * PGRelabelType represents a "dummy" type coercion between two binary- * compatible datatypes, such as reinterpreting the result of an OID * expression as an int4. It is a no-op at runtime; we only need it * to provide a place to store the correct type to be attributed to * the expression result during type resolution. (We can't get away * with just overwriting the type field of the input expression node, * so we need a separate node to show the coercion's result type.) * ---------------- */ typedef struct PGRelabelType { PGExpr xpr; PGExpr *arg; /* input expression */ PGOid resulttype; /* output type of coercion expression */ int32_t resulttypmod; /* output typmod (usually -1) */ PGOid resultcollid; /* OID of collation, or InvalidOid if none */ PGCoercionForm relabelformat; /* how to display this node */ int location; /* token location, or -1 if unknown */ } PGRelabelType; /* ---------------- * PGCoerceViaIO * * PGCoerceViaIO represents a type coercion between two types whose textual * representations are compatible, implemented by invoking the source type's * typoutput function then the destination type's typinput function. * ---------------- */ typedef struct PGCoerceViaIO { PGExpr xpr; PGExpr *arg; /* input expression */ PGOid resulttype; /* output type of coercion */ /* output typmod is not stored, but is presumed -1 */ PGOid resultcollid; /* OID of collation, or InvalidOid if none */ PGCoercionForm coerceformat; /* how to display this node */ int location; /* token location, or -1 if unknown */ } PGCoerceViaIO; /* ---------------- * PGArrayCoerceExpr * * PGArrayCoerceExpr represents a type coercion from one array type to another, * which is implemented by applying the indicated element-type coercion * function to each element of the source array. If elemfuncid is InvalidOid * then the element types are binary-compatible, but the coercion still * requires some effort (we have to fix the element type ID stored in the * array header). * ---------------- */ typedef struct PGArrayCoerceExpr { PGExpr xpr; PGExpr *arg; /* input expression (yields an array) */ PGOid elemfuncid; /* OID of element coercion function, or 0 */ PGOid resulttype; /* output type of coercion (an array type) */ int32_t resulttypmod; /* output typmod (also element typmod) */ PGOid resultcollid; /* OID of collation, or InvalidOid if none */ bool isExplicit; /* conversion semantics flag to pass to func */ PGCoercionForm coerceformat; /* how to display this node */ int location; /* token location, or -1 if unknown */ } PGArrayCoerceExpr; /* ---------------- * PGConvertRowtypeExpr * * PGConvertRowtypeExpr represents a type coercion from one composite type * to another, where the source type is guaranteed to contain all the columns * needed for the destination type plus possibly others; the columns need not * be in the same positions, but are matched up by name. This is primarily * used to convert a whole-row value of an inheritance child table into a * valid whole-row value of its parent table's rowtype. * ---------------- */ typedef struct PGConvertRowtypeExpr { PGExpr xpr; PGExpr *arg; /* input expression */ PGOid resulttype; /* output type (always a composite type) */ /* Like PGRowExpr, we deliberately omit a typmod and collation here */ PGCoercionForm convertformat; /* how to display this node */ int location; /* token location, or -1 if unknown */ } PGConvertRowtypeExpr; /*---------- * PGCollateExpr - COLLATE * * The planner replaces PGCollateExpr with PGRelabelType during expression * preprocessing, so execution never sees a CollateExpr. *---------- */ typedef struct PGCollateExpr { PGExpr xpr; PGExpr *arg; /* input expression */ PGOid collOid; /* collation's OID */ int location; /* token location, or -1 if unknown */ } PGCollateExpr; /*---------- * PGCaseExpr - a CASE expression * * We support two distinct forms of CASE expression: * CASE WHEN boolexpr THEN expr [ WHEN boolexpr THEN expr ... ] * CASE testexpr WHEN compexpr THEN expr [ WHEN compexpr THEN expr ... ] * These are distinguishable by the "arg" field being NULL in the first case * and the testexpr in the second case. * * In the raw grammar output for the second form, the condition expressions * of the WHEN clauses are just the comparison values. Parse analysis * converts these to valid boolean expressions of the form * PGCaseTestExpr '=' compexpr * where the PGCaseTestExpr node is a placeholder that emits the correct * value at runtime. This structure is used so that the testexpr need be * evaluated only once. Note that after parse analysis, the condition * expressions always yield boolean. * * Note: we can test whether a PGCaseExpr has been through parse analysis * yet by checking whether casetype is InvalidOid or not. *---------- */ typedef struct PGCaseExpr { PGExpr xpr; PGOid casetype; /* type of expression result */ PGOid casecollid; /* OID of collation, or InvalidOid if none */ PGExpr *arg; /* implicit equality comparison argument */ PGList *args; /* the arguments (list of WHEN clauses) */ PGExpr *defresult; /* the default result (ELSE clause) */ int location; /* token location, or -1 if unknown */ } PGCaseExpr; /* * PGCaseWhen - one arm of a CASE expression */ typedef struct PGCaseWhen { PGExpr xpr; PGExpr *expr; /* condition expression */ PGExpr *result; /* substitution result */ int location; /* token location, or -1 if unknown */ } PGCaseWhen; /* * Placeholder node for the test value to be processed by a CASE expression. * This is effectively like a PGParam, but can be implemented more simply * since we need only one replacement value at a time. * * We also use this in nested UPDATE expressions. * See transformAssignmentIndirection(). */ typedef struct PGCaseTestExpr { PGExpr xpr; PGOid typeId; /* type for substituted value */ int32_t typeMod; /* typemod for substituted value */ PGOid collation; /* collation for the substituted value */ } PGCaseTestExpr; /* * PGArrayExpr - an ARRAY[] expression * * Note: if multidims is false, the constituent expressions all yield the * scalar type identified by element_typeid. If multidims is true, the * constituent expressions all yield arrays of element_typeid (ie, the same * type as array_typeid); at runtime we must check for compatible subscripts. */ typedef struct PGArrayExpr { PGExpr xpr; PGOid array_typeid; /* type of expression result */ PGOid array_collid; /* OID of collation, or InvalidOid if none */ PGOid element_typeid; /* common type of array elements */ PGList *elements; /* the array elements or sub-arrays */ bool multidims; /* true if elements are sub-arrays */ int location; /* token location, or -1 if unknown */ } PGArrayExpr; /* * PGRowExpr - a ROW() expression * * Note: the list of fields must have a one-for-one correspondence with * physical fields of the associated rowtype, although it is okay for it * to be shorter than the rowtype. That is, the N'th list element must * match up with the N'th physical field. When the N'th physical field * is a dropped column (attisdropped) then the N'th list element can just * be a NULL constant. (This case can only occur for named composite types, * not RECORD types, since those are built from the PGRowExpr itself rather * than vice versa.) It is important not to assume that length(args) is * the same as the number of columns logically present in the rowtype. * * colnames provides field names in cases where the names can't easily be * obtained otherwise. Names *must* be provided if row_typeid is RECORDOID. * If row_typeid identifies a known composite type, colnames can be NIL to * indicate the type's cataloged field names apply. Note that colnames can * be non-NIL even for a composite type, and typically is when the PGRowExpr * was created by expanding a whole-row Var. This is so that we can retain * the column alias names of the RTE that the PGVar referenced (which would * otherwise be very difficult to extract from the parsetree). Like the * args list, colnames is one-for-one with physical fields of the rowtype. */ typedef struct PGRowExpr { PGExpr xpr; PGList *args; /* the fields */ PGOid row_typeid; /* RECORDOID or a composite type's ID */ /* * Note: we deliberately do NOT store a typmod. Although a typmod will be * associated with specific RECORD types at runtime, it will differ for * different backends, and so cannot safely be stored in stored * parsetrees. We must assume typmod -1 for a PGRowExpr node. * * We don't need to store a collation either. The result type is * necessarily composite, and composite types never have a collation. */ PGCoercionForm row_format; /* how to display this node */ PGList *colnames; /* list of String, or NIL */ int location; /* token location, or -1 if unknown */ } PGRowExpr; /* * PGRowCompareExpr - row-wise comparison, such as (a, b) <= (1, 2) * * We support row comparison for any operator that can be determined to * act like =, <>, <, <=, >, or >= (we determine this by looking for the * operator in btree opfamilies). Note that the same operator name might * map to a different operator for each pair of row elements, since the * element datatypes can vary. * * A PGRowCompareExpr node is only generated for the < <= > >= cases; * the = and <> cases are translated to simple AND or OR combinations * of the pairwise comparisons. However, we include = and <> in the * PGRowCompareType enum for the convenience of parser logic. */ typedef enum PGRowCompareType { /* Values of this enum are chosen to match btree strategy numbers */ PG_ROWCOMPARE_LT = 1, /* BTLessStrategyNumber */ PG_ROWCOMPARE_LE = 2, /* BTLessEqualStrategyNumber */ PG_ROWCOMPARE_EQ = 3, /* BTEqualStrategyNumber */ PG_ROWCOMPARE_GE = 4, /* BTGreaterEqualStrategyNumber */ PG_ROWCOMPARE_GT = 5, /* BTGreaterStrategyNumber */ PG_ROWCOMPARE_NE = 6 /* no such btree strategy */ } PGRowCompareType; typedef struct PGRowCompareExpr { PGExpr xpr; PGRowCompareType rctype; /* LT LE GE or GT, never EQ or NE */ PGList *opnos; /* OID list of pairwise comparison ops */ PGList *opfamilies; /* OID list of containing operator families */ PGList *inputcollids; /* OID list of collations for comparisons */ PGList *largs; /* the left-hand input arguments */ PGList *rargs; /* the right-hand input arguments */ } PGRowCompareExpr; /* * PGCoalesceExpr - a COALESCE expression */ typedef struct PGCoalesceExpr { PGExpr xpr; PGOid coalescetype; /* type of expression result */ PGOid coalescecollid; /* OID of collation, or InvalidOid if none */ PGList *args; /* the arguments */ int location; /* token location, or -1 if unknown */ } PGCoalesceExpr; /* * PGMinMaxExpr - a GREATEST or LEAST function */ typedef enum PGMinMaxOp { PG_IS_GREATEST, IS_LEAST } PGMinMaxOp; typedef struct PGMinMaxExpr { PGExpr xpr; PGOid minmaxtype; /* common type of arguments and result */ PGOid minmaxcollid; /* OID of collation of result */ PGOid inputcollid; /* OID of collation that function should use */ PGMinMaxOp op; /* function to execute */ PGList *args; /* the arguments */ int location; /* token location, or -1 if unknown */ } PGMinMaxExpr; /* * PGSQLValueFunction - parameterless functions with special grammar productions * * The SQL standard categorizes some of these as * and others as . We call 'em SQLValueFunctions * for lack of a better term. We store type and typmod of the result so that * some code doesn't need to know each function individually, and because * we would need to store typmod anyway for some of the datetime functions. * Note that currently, all variants return non-collating datatypes, so we do * not need a collation field; also, all these functions are stable. */ typedef enum PGSQLValueFunctionOp { PG_SVFOP_CURRENT_DATE, PG_SVFOP_CURRENT_TIME, PG_SVFOP_CURRENT_TIME_N, PG_SVFOP_CURRENT_TIMESTAMP, PG_SVFOP_CURRENT_TIMESTAMP_N, PG_SVFOP_LOCALTIME, PG_SVFOP_LOCALTIME_N, PG_SVFOP_LOCALTIMESTAMP, PG_SVFOP_LOCALTIMESTAMP_N, PG_SVFOP_CURRENT_ROLE, PG_SVFOP_CURRENT_USER, PG_SVFOP_USER, PG_SVFOP_SESSION_USER, PG_SVFOP_CURRENT_CATALOG, PG_SVFOP_CURRENT_SCHEMA } PGSQLValueFunctionOp; typedef struct PGSQLValueFunction { PGExpr xpr; PGSQLValueFunctionOp op; /* which function this is */ PGOid type; /* result type/typmod */ int32_t typmod; int location; /* token location, or -1 if unknown */ } PGSQLValueFunction; /* ---------------- * PGNullTest * * PGNullTest represents the operation of testing a value for NULLness. * The appropriate test is performed and returned as a boolean Datum. * * When argisrow is false, this simply represents a test for the null value. * * When argisrow is true, the input expression must yield a rowtype, and * the node implements "row IS [NOT] NULL" per the SQL standard. This * includes checking individual fields for NULLness when the row datum * itself isn't NULL. * * NOTE: the combination of a rowtype input and argisrow==false does NOT * correspond to the SQL notation "row IS [NOT] NULL"; instead, this case * represents the SQL notation "row IS [NOT] DISTINCT FROM NULL". * ---------------- */ typedef enum PGNullTestType { PG_IS_NULL, IS_NOT_NULL } PGNullTestType; typedef struct PGNullTest { PGExpr xpr; PGExpr *arg; /* input expression */ PGNullTestType nulltesttype; /* IS NULL, IS NOT NULL */ bool argisrow; /* T to perform field-by-field null checks */ int location; /* token location, or -1 if unknown */ } PGNullTest; /* * PGBooleanTest * * PGBooleanTest represents the operation of determining whether a boolean * is true, false, or UNKNOWN (ie, NULL). All six meaningful combinations * are supported. Note that a NULL input does *not* cause a NULL result. * The appropriate test is performed and returned as a boolean Datum. */ typedef enum PGBoolTestType { PG_IS_TRUE, IS_NOT_TRUE, IS_FALSE, IS_NOT_FALSE, IS_UNKNOWN, IS_NOT_UNKNOWN } PGBoolTestType; typedef struct PGBooleanTest { PGExpr xpr; PGExpr *arg; /* input expression */ PGBoolTestType booltesttype; /* test type */ int location; /* token location, or -1 if unknown */ } PGBooleanTest; /* * PGCoerceToDomain * * PGCoerceToDomain represents the operation of coercing a value to a domain * type. At runtime (and not before) the precise set of constraints to be * checked will be determined. If the value passes, it is returned as the * result; if not, an error is raised. Note that this is equivalent to * PGRelabelType in the scenario where no constraints are applied. */ typedef struct PGCoerceToDomain { PGExpr xpr; PGExpr *arg; /* input expression */ PGOid resulttype; /* domain type ID (result type) */ int32_t resulttypmod; /* output typmod (currently always -1) */ PGOid resultcollid; /* OID of collation, or InvalidOid if none */ PGCoercionForm coercionformat; /* how to display this node */ int location; /* token location, or -1 if unknown */ } PGCoerceToDomain; /* * Placeholder node for the value to be processed by a domain's check * constraint. This is effectively like a PGParam, but can be implemented more * simply since we need only one replacement value at a time. * * Note: the typeId/typeMod/collation will be set from the domain's base type, * not the domain itself. This is because we shouldn't consider the value * to be a member of the domain if we haven't yet checked its constraints. */ typedef struct PGCoerceToDomainValue { PGExpr xpr; PGOid typeId; /* type for substituted value */ int32_t typeMod; /* typemod for substituted value */ PGOid collation; /* collation for the substituted value */ int location; /* token location, or -1 if unknown */ } PGCoerceToDomainValue; /* * Placeholder node for a DEFAULT marker in an INSERT or UPDATE command. * * This is not an executable expression: it must be replaced by the actual * column default expression during rewriting. But it is convenient to * treat it as an expression node during parsing and rewriting. */ typedef struct PGSetToDefault { PGExpr xpr; PGOid typeId; /* type for substituted value */ int32_t typeMod; /* typemod for substituted value */ PGOid collation; /* collation for the substituted value */ int location; /* token location, or -1 if unknown */ } PGSetToDefault; /* * PGNode representing [WHERE] CURRENT OF cursor_name * * CURRENT OF is a bit like a PGVar, in that it carries the rangetable index * of the target relation being constrained; this aids placing the expression * correctly during planning. We can assume however that its "levelsup" is * always zero, due to the syntactic constraints on where it can appear. * * The referenced cursor can be represented either as a hardwired string * or as a reference to a run-time parameter of type REFCURSOR. The latter * case is for the convenience of plpgsql. */ typedef struct PGCurrentOfExpr { PGExpr xpr; PGIndex cvarno; /* RT index of target relation */ char *cursor_name; /* name of referenced cursor, or NULL */ int cursor_param; /* refcursor parameter number, or 0 */ } PGCurrentOfExpr; /* * PGNextValueExpr - get next value from sequence * * This has the same effect as calling the nextval() function, but it does not * check permissions on the sequence. This is used for identity columns, * where the sequence is an implicit dependency without its own permissions. */ typedef struct PGNextValueExpr { PGExpr xpr; PGOid seqid; PGOid typeId; } PGNextValueExpr; /* * PGInferenceElem - an element of a unique index inference specification * * This mostly matches the structure of IndexElems, but having a dedicated * primnode allows for a clean separation between the use of index parameters * by utility commands, and this node. */ typedef struct PGInferenceElem { PGExpr xpr; PGNode *expr; /* expression to infer from, or NULL */ PGOid infercollid; /* OID of collation, or InvalidOid */ PGOid inferopclass; /* OID of att opclass, or InvalidOid */ } PGInferenceElem; /*-------------------- * PGTargetEntry - * a target entry (used in query target lists) * * Strictly speaking, a PGTargetEntry isn't an expression node (since it can't * be evaluated by ExecEvalExpr). But we treat it as one anyway, since in * very many places it's convenient to process a whole query targetlist as a * single expression tree. * * In a SELECT's targetlist, resno should always be equal to the item's * ordinal position (counting from 1). However, in an INSERT or UPDATE * targetlist, resno represents the attribute number of the destination * column for the item; so there may be missing or out-of-order resnos. * It is even legal to have duplicated resnos; consider * UPDATE table SET arraycol[1] = ..., arraycol[2] = ..., ... * The two meanings come together in the executor, because the planner * transforms INSERT/UPDATE tlists into a normalized form with exactly * one entry for each column of the destination table. Before that's * happened, however, it is risky to assume that resno == position. * Generally get_tle_by_resno() should be used rather than list_nth() * to fetch tlist entries by resno, and only in SELECT should you assume * that resno is a unique identifier. * * resname is required to represent the correct column name in non-resjunk * entries of top-level SELECT targetlists, since it will be used as the * column title sent to the frontend. In most other contexts it is only * a debugging aid, and may be wrong or even NULL. (In particular, it may * be wrong in a tlist from a stored rule, if the referenced column has been * renamed by ALTER TABLE since the rule was made. Also, the planner tends * to store NULL rather than look up a valid name for tlist entries in * non-toplevel plan nodes.) In resjunk entries, resname should be either * a specific system-generated name (such as "ctid") or NULL; anything else * risks confusing ExecGetJunkAttribute! * * ressortgroupref is used in the representation of ORDER BY, GROUP BY, and * DISTINCT items. Targetlist entries with ressortgroupref=0 are not * sort/group items. If ressortgroupref>0, then this item is an ORDER BY, * GROUP BY, and/or DISTINCT target value. No two entries in a targetlist * may have the same nonzero ressortgroupref --- but there is no particular * meaning to the nonzero values, except as tags. (For example, one must * not assume that lower ressortgroupref means a more significant sort key.) * The order of the associated PGSortGroupClause lists determine the semantics. * * resorigtbl/resorigcol identify the source of the column, if it is a * simple reference to a column of a base table (or view). If it is not * a simple reference, these fields are zeroes. * * If resjunk is true then the column is a working column (such as a sort key) * that should be removed from the final output of the query. Resjunk columns * must have resnos that cannot duplicate any regular column's resno. Also * note that there are places that assume resjunk columns come after non-junk * columns. *-------------------- */ typedef struct PGTargetEntry { PGExpr xpr; PGExpr *expr; /* expression to evaluate */ PGAttrNumber resno; /* attribute number (see notes above) */ char *resname; /* name of the column (could be NULL) */ PGIndex ressortgroupref; /* nonzero if referenced by a sort/group * clause */ PGOid resorigtbl; /* OID of column's source table */ PGAttrNumber resorigcol; /* column's number in source table */ bool resjunk; /* set to true to eliminate the attribute from * final target list */ } PGTargetEntry; /* ---------------------------------------------------------------- * node types for join trees * * The leaves of a join tree structure are PGRangeTblRef nodes. Above * these, PGJoinExpr nodes can appear to denote a specific kind of join * or qualified join. Also, PGFromExpr nodes can appear to denote an * ordinary cross-product join ("FROM foo, bar, baz WHERE ..."). * PGFromExpr is like a PGJoinExpr of jointype PG_JOIN_INNER, except that it * may have any number of child nodes, not just two. * * NOTE: the top level of a Query's jointree is always a FromExpr. * Even if the jointree contains no rels, there will be a FromExpr. * * NOTE: the qualification expressions present in PGJoinExpr nodes are * *in addition to* the query's main WHERE clause, which appears as the * qual of the top-level FromExpr. The reason for associating quals with * specific nodes in the jointree is that the position of a qual is critical * when outer joins are present. (If we enforce a qual too soon or too late, * that may cause the outer join to produce the wrong set of NULL-extended * rows.) If all joins are inner joins then all the qual positions are * semantically interchangeable. * * NOTE: in the raw output of gram.y, a join tree contains PGRangeVar, * PGRangeSubselect, and PGRangeFunction nodes, which are all replaced by * PGRangeTblRef nodes during the parse analysis phase. Also, the top-level * PGFromExpr is added during parse analysis; the grammar regards FROM and * WHERE as separate. * ---------------------------------------------------------------- */ /* * PGRangeTblRef - reference to an entry in the query's rangetable * * We could use direct pointers to the RT entries and skip having these * nodes, but multiple pointers to the same node in a querytree cause * lots of headaches, so it seems better to store an index into the RT. */ typedef struct PGRangeTblRef { PGNodeTag type; int rtindex; } PGRangeTblRef; /*---------- * PGJoinExpr - for SQL JOIN expressions * * joinreftype, usingClause, and quals are interdependent. The user can write * only one of NATURAL, USING(), or ON() (this is enforced by the grammar). * If he writes NATURAL then parse analysis generates the equivalent USING() * list, and from that fills in "quals" with the right equality comparisons. * If he writes USING() then "quals" is filled with equality comparisons. * If he writes ON() then only "quals" is set. Note that NATURAL/USING * are not equivalent to ON() since they also affect the output column list. * * alias is an PGAlias node representing the AS alias-clause attached to the * join expression, or NULL if no clause. NB: presence or absence of the * alias has a critical impact on semantics, because a join with an alias * restricts visibility of the tables/columns inside it. * * During parse analysis, an RTE is created for the PGJoin, and its index * is filled into rtindex. This RTE is present mainly so that Vars can * be created that refer to the outputs of the join. The planner sometimes * generates JoinExprs internally; these can have rtindex = 0 if there are * no join alias variables referencing such joins. *---------- */ typedef struct PGJoinExpr { PGNodeTag type; PGJoinType jointype; /* type of join */ PGJoinRefType joinreftype; /* Regular/Natural/AsOf join? Will need to shape table */ PGNode *larg; /* left subtree */ PGNode *rarg; /* right subtree */ PGList *usingClause; /* USING clause, if any (list of String) */ PGNode *quals; /* qualifiers on join, if any */ PGAlias *alias; /* user-written alias clause, if any */ int rtindex; /* RT index assigned for join, or 0 */ int location; /* token location, or -1 if unknown */ } PGJoinExpr; /*---------- * PGFromExpr - represents a FROM ... WHERE ... construct * * This is both more flexible than a PGJoinExpr (it can have any number of * children, including zero) and less so --- we don't need to deal with * aliases and so on. The output column set is implicitly just the union * of the outputs of the children. *---------- */ typedef struct PGFromExpr { PGNodeTag type; PGList *fromlist; /* PGList of join subtrees */ PGNode *quals; /* qualifiers on join, if any */ } PGFromExpr; /*---------- * PGOnConflictExpr - represents an ON CONFLICT DO ... expression * * The optimizer requires a list of inference elements, and optionally a WHERE * clause to infer a unique index. The unique index (or, occasionally, * indexes) inferred are used to arbitrate whether or not the alternative ON * CONFLICT path is taken. *---------- */ typedef struct PGOnConflictExpr { PGNodeTag type; PGOnConflictAction action; /* DO NOTHING or UPDATE? */ /* Arbiter */ PGList *arbiterElems; /* unique index arbiter list (of * InferenceElem's) */ PGNode *arbiterWhere; /* unique index arbiter WHERE clause */ PGOid constraint; /* pg_constraint OID for arbiter */ /* ON CONFLICT UPDATE */ PGList *onConflictSet; /* PGList of ON CONFLICT SET TargetEntrys */ PGNode *onConflictWhere; /* qualifiers to restrict UPDATE to */ int exclRelIndex; /* RT index of 'excluded' relation */ PGList *exclRelTlist; /* tlist of the EXCLUDED pseudo relation */ } PGOnConflictExpr; /* * PGAtClause - AT clause in FROM tables - e.g. "AT (TIMESTAMP => NOW()) */ typedef struct PGAtClause { PGNodeTag type; const char *unit; /* the unit (e.g. TIMESTAMP/VERSION) */ PGNode *expr; /* the expression */ } PGAtClause; }