* and join trees.
*
*
- * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: primnodes.h,v 1.64 2002/06/20 20:29:51 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.148 2009/04/05 19:59:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "access/attnum.h"
#include "nodes/pg_list.h"
-/* FunctionCache is declared in utils/fcache.h */
-typedef struct FunctionCache *FunctionCachePtr;
-
/* ----------------------------------------------------------------
* node definitions
* ----------------------------------------------------------------
*/
-/*--------------------
- * Resdom (Result Domain)
- *
- * Notes:
- * ressortgroupref is the parse/plan-time representation of ORDER BY and
- * GROUP BY items. Targetlist entries with ressortgroupref=0 are not
- * sort/group items. If ressortgroupref>0, then this item is an ORDER BY or
- * GROUP BY 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 SortClause or GroupClause lists determine the semantics.
- *
- * reskey and reskeyop are the execution-time representation of sorting.
- * reskey must be zero in any non-sort-key item. The reskey of sort key
- * targetlist items for a sort plan node is 1,2,...,n for the n sort keys.
- * The reskeyop of each such targetlist item is the sort operator's OID.
- * reskeyop will be zero in non-sort-key items.
- *
- * Both reskey and reskeyop are typically zero during parse/plan stages.
- * The executor does not pay any attention to ressortgroupref.
- *--------------------
- */
-typedef struct Resdom
-{
- NodeTag type;
- AttrNumber resno; /* attribute number */
- Oid restype; /* type of the value */
- int32 restypmod; /* type-specific modifier of the value */
- char *resname; /* name of the resdom (could be NULL) */
- Index ressortgroupref;
- /* nonzero if referenced by a sort/group clause */
- Index reskey; /* order of key in a sort (for those > 0) */
- Oid reskeyop; /* sort operator's Oid */
- bool resjunk; /* set to true to eliminate the attribute
- * from final target list */
-} Resdom;
-
-/*
- * Fjoin
- */
-typedef struct Fjoin
-{
- NodeTag type;
- bool fj_initialized; /* true if the Fjoin has already been
- * initialized for the current target list
- * evaluation */
- int fj_nNodes; /* The number of Iter nodes returning sets
- * that the node will flatten */
- List *fj_innerNode; /* exactly one Iter node. We eval every
- * node in the outerList once then eval
- * the inner node to completion pair the
- * outerList result vector with each inner
- * result to form the full result. When
- * the inner has been exhausted, we get
- * the next outer result vector and reset
- * the inner. */
- DatumPtr fj_results; /* The complete (flattened) result vector */
- BoolPtr fj_alwaysDone; /* a null vector to indicate sets with a
- * cardinality of 0, we treat them as the
- * set {NULL}. */
-} Fjoin;
-
-
/*
* Alias -
* specifies an alias for a range variable; the alias might also
* specify renaming of columns within the table.
+ *
+ * Note: colnames is a list of Value nodes (always strings). In Alias structs
+ * associated with RTEs, there may be entries corresponding to dropped
+ * columns; these are normally empty strings (""). See parsenodes.h for info.
*/
typedef struct Alias
{
NodeTag type;
char *aliasname; /* aliased rel name (never qualified) */
List *colnames; /* optional list of column aliases */
- /* Note: colnames is a list of Value nodes (always strings) */
} Alias;
typedef enum InhOption
INH_DEFAULT /* Use current SQL_inheritance option */
} InhOption;
+/* What to do at commit time for temporary relations */
+typedef enum OnCommitAction
+{
+ ONCOMMIT_NOOP, /* No ON COMMIT clause (do nothing) */
+ ONCOMMIT_PRESERVE_ROWS, /* ON COMMIT PRESERVE ROWS (do nothing) */
+ ONCOMMIT_DELETE_ROWS, /* ON COMMIT DELETE ROWS */
+ ONCOMMIT_DROP /* ON COMMIT DROP */
+} OnCommitAction;
+
/*
* RangeVar - range variable, used in FROM clauses
*
char *catalogname; /* the catalog (database) name, or NULL */
char *schemaname; /* the schema name, or NULL */
char *relname; /* the relation/sequence name */
- InhOption inhOpt; /* expand rel by inheritance?
- * recursively act on children? */
+ InhOption inhOpt; /* expand rel by inheritance? recursively act
+ * on children? */
bool istemp; /* is this a temp relation/sequence? */
Alias *alias; /* table alias & optional column aliases */
+ int location; /* token location, or -1 if unknown */
} RangeVar;
+/*
+ * IntoClause - target information for SELECT INTO and CREATE TABLE AS
+ */
+typedef struct IntoClause
+{
+ NodeTag type;
+
+ RangeVar *rel; /* target relation name */
+ List *colNames; /* column names to assign, or NIL */
+ List *options; /* options from WITH clause */
+ OnCommitAction onCommit; /* what do we do at COMMIT? */
+ char *tableSpaceName; /* table space to use, or NULL */
+} IntoClause;
+
/* ----------------------------------------------------------------
* node types for executable expressions
*/
/*
- * Expr
+ * Expr - generic superclass for executable-expression nodes
+ *
+ * All node types that are used in executable expression trees should derive
+ * from Expr (that is, have Expr as their first field). Since Expr only
+ * contains NodeTag, this is a formality, but it is an easy form of
+ * documentation. See also the ExprState node types in execnodes.h.
*/
-typedef enum OpType
-{
- OP_EXPR, FUNC_EXPR, OR_EXPR, AND_EXPR, NOT_EXPR, SUBPLAN_EXPR
-} OpType;
-
typedef struct Expr
{
NodeTag type;
- Oid typeOid; /* oid of the type of this expression */
- OpType opType; /* kind of expression */
- Node *oper; /* operator node if needed (Oper, Func, or
- * SubPlan) */
- List *args; /* arguments to this expression */
} Expr;
/*
- * Oper - Expr subnode for an OP_EXPR
- *
- * NOTE: in the good old days 'opno' used to be both (or either, or
- * neither) the pg_operator oid, and/or the pg_proc oid depending
- * on the postgres module in question (parser->pg_operator,
- * executor->pg_proc, planner->both), the mood of the programmer,
- * and the phase of the moon (rumors that it was also depending on the day
- * of the week are probably false). To make things even more postgres-like
- * (i.e. a mess) some comments were referring to 'opno' using the name
- * 'opid'. Anyway, now we have two separate fields, and of course that
- * immediately removes all bugs from the code... [ sp :-) ].
- *
- * Note also that opid 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 opid is typically 0.
- */
-typedef struct Oper
-{
- NodeTag type;
- Oid opno; /* PG_OPERATOR OID of the operator */
- Oid opid; /* PG_PROC OID of underlying function */
- Oid opresulttype; /* PG_TYPE OID of result value */
- bool opretset; /* true if operator returns set */
- FunctionCachePtr op_fcache; /* runtime state, else NULL */
-} Oper;
-
-/*
- * Func - Expr subnode for a FUNC_EXPR
- */
-typedef struct Func
-{
- NodeTag type;
- Oid funcid; /* PG_PROC OID of the function */
- Oid funcresulttype; /* PG_TYPE OID of result value */
- bool funcretset; /* true if function returns set */
- FunctionCachePtr func_fcache; /* runtime state, or NULL */
-} Func;
-
-/*
- * Var
+ * Var - 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, Var nodes appearing in
typedef struct Var
{
- NodeTag type;
- Index varno; /* index of this var's relation in the
- * range table (could also be INNER or
- * OUTER) */
- AttrNumber varattno; /* attribute number of this var, or zero
- * for all */
- Oid vartype; /* pg_type tuple OID for the type of this
- * var */
+ Expr xpr;
+ Index varno; /* index of this var's relation in the range
+ * table (could also be INNER or OUTER) */
+ AttrNumber varattno; /* attribute number of this var, or zero for
+ * all */
+ Oid vartype; /* pg_type OID for the type of this var */
int32 vartypmod; /* pg_attribute typmod value */
- Index varlevelsup;
-
- /*
- * for subquery variables referencing outer relations; 0 in a normal
- * var, >0 means N levels up
- */
+ Index varlevelsup; /* for subquery variables referencing outer
+ * relations; 0 in a normal var, >0 means N
+ * levels up */
Index varnoold; /* original value of varno, for debugging */
AttrNumber varoattno; /* original value of varattno */
+ int location; /* token location, or -1 if unknown */
} Var;
/*
*/
typedef struct Const
{
- NodeTag type;
- Oid consttype; /* PG_TYPE OID of the constant's value */
- int constlen; /* length in bytes of the constant's value */
+ Expr xpr;
+ Oid consttype; /* pg_type OID of the constant's datatype */
+ int32 consttypmod; /* typmod value, if any */
+ int constlen; /* typlen of the constant's datatype */
Datum constvalue; /* the constant's value */
bool constisnull; /* whether the constant is null (if true,
- * the other fields are undefined) */
- bool constbyval; /* whether the information in constvalue
- * if passed by value. If true, then all
- * the information is stored in the datum.
- * If false, then the datum contains a
- * pointer to the information. */
- bool constisset; /* whether the const represents a set. The
- * const value corresponding will be the
- * query that defines the set. */
- bool constiscast;
+ * 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 Datum
+ * contains a pointer to the information. */
+ int location; /* token location, or -1 if unknown */
} Const;
/* ----------------
* Param
* paramkind - specifies the kind of parameter. The possible values
- * for this field are specified in "params.h", and they are:
+ * for this field are:
*
- * PARAM_NAMED: The parameter has a name, i.e. something
- * like `$.salary' or `$.foobar'.
- * In this case field `paramname' must be a valid Name.
+ * PARAM_EXTERN: The parameter value is supplied from outside the plan.
+ * Such parameters are numbered from 1 to n.
*
- * PARAM_NUM: The parameter has only a numeric identifier,
- * i.e. something like `$1', `$2' etc.
- * The number is contained in the `paramid' field.
+ * PARAM_EXEC: The parameter is an internal executor parameter, used
+ * for passing values into and out of sub-queries.
+ * For historical reasons, such parameters are numbered from 0.
+ * These numbers are independent of PARAM_EXTERN numbers.
*
- * PARAM_NEW: Used in PRS2 rule, similar to PARAM_NAMED.
- * The `paramname' and `paramid' refer to the "NEW" tuple
- * The `pramname' is the attribute name and `paramid'
- * is the attribute number.
+ * PARAM_SUBLINK: The parameter represents an output column of a SubLink
+ * node's sub-select. The column number is contained in the
+ * `paramid' field. (This type of Param is converted to
+ * PARAM_EXEC during planning.)
*
- * PARAM_OLD: Same as PARAM_NEW, but in this case we refer to
- * the "OLD" tuple.
+ * Note: currently, paramtypmod is valid for PARAM_SUBLINK Params, and for
+ * PARAM_EXEC Params generated from them; it is always -1 for PARAM_EXTERN
+ * params, since the APIs that supply values for such parameters don't carry
+ * any typmod info.
* ----------------
*/
+typedef enum ParamKind
+{
+ PARAM_EXTERN,
+ PARAM_EXEC,
+ PARAM_SUBLINK
+} ParamKind;
+
typedef struct Param
{
- NodeTag type;
- int paramkind; /* specifies the kind of parameter. See
- * above */
- AttrNumber paramid; /* numeric identifier for literal-constant
- * parameters ("$1") */
- char *paramname; /* attribute name for tuple-substitution
- * parameters ("$.foo") */
- Oid paramtype; /* PG_TYPE OID of the parameter's value */
+ Expr xpr;
+ ParamKind paramkind; /* kind of parameter. See above */
+ int paramid; /* numeric ID for parameter */
+ Oid paramtype; /* pg_type OID of parameter's datatype */
+ int32 paramtypmod; /* typmod value, if known */
+ int location; /* token location, or -1 if unknown */
} Param;
/*
*/
typedef struct Aggref
{
- NodeTag type;
+ Expr xpr;
Oid aggfnoid; /* pg_proc Oid of the aggregate */
Oid aggtype; /* type Oid of result of the aggregate */
- Node *target; /* expression we are aggregating on */
- bool aggstar; /* TRUE if argument was really '*' */
+ List *args; /* arguments to the aggregate */
+ Index agglevelsup; /* > 0 if agg belongs to outer query */
+ bool aggstar; /* TRUE if argument list was really '*' */
bool aggdistinct; /* TRUE if it's agg(DISTINCT ...) */
- int aggno; /* workspace for executor (see nodeAgg.c) */
+ int location; /* token location, or -1 if unknown */
} Aggref;
+/*
+ * WindowFunc
+ */
+typedef struct WindowFunc
+{
+ Expr xpr;
+ Oid winfnoid; /* pg_proc Oid of the function */
+ Oid wintype; /* type Oid of result of the window function */
+ List *args; /* arguments to the window function */
+ Index winref; /* index of associated WindowClause */
+ bool winstar; /* TRUE if argument list was really '*' */
+ bool winagg; /* is function a simple aggregate? */
+ int location; /* token location, or -1 if unknown */
+} WindowFunc;
+
/* ----------------
+ * ArrayRef: describes an array subscripting operation
+ *
+ * An ArrayRef 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.
+ *
+ * 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.
+ * ----------------
+ */
+typedef struct ArrayRef
+{
+ Expr xpr;
+ Oid refarraytype; /* type of the array proper */
+ Oid refelemtype; /* type of the array elements */
+ int32 reftypmod; /* typmod of the array (and elements too) */
+ List *refupperindexpr;/* expressions that evaluate to upper array
+ * indexes */
+ List *reflowerindexpr;/* expressions that evaluate to lower array
+ * indexes */
+ Expr *refexpr; /* the expression that evaluates to an array
+ * value */
+ Expr *refassgnexpr; /* expression for the source value, or NULL if
+ * fetch */
+} ArrayRef;
+
+/*
+ * CoercionContext - 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 CoercionContext
+{
+ COERCION_IMPLICIT, /* coercion in context of expression */
+ COERCION_ASSIGNMENT, /* coercion in context of assignment */
+ COERCION_EXPLICIT /* explicit cast operation */
+} CoercionContext;
+
+/*
+ * CoercionForm - information showing how to display a function-call node
+ */
+typedef enum CoercionForm
+{
+ COERCE_EXPLICIT_CALL, /* display as a function call */
+ COERCE_EXPLICIT_CAST, /* display as an explicit cast */
+ COERCE_IMPLICIT_CAST, /* implicit cast, so hide it */
+ COERCE_DONTCARE /* special case for planner */
+} CoercionForm;
+
+/*
+ * FuncExpr - expression node for a function call
+ */
+typedef struct FuncExpr
+{
+ Expr xpr;
+ Oid funcid; /* PG_PROC OID of the function */
+ Oid funcresulttype; /* PG_TYPE OID of result value */
+ bool funcretset; /* true if function returns set */
+ CoercionForm funcformat; /* how to display this function call */
+ List *args; /* arguments to the function */
+ int location; /* token location, or -1 if unknown */
+} FuncExpr;
+
+/*
+ * OpExpr - 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 OpExpr
+{
+ Expr xpr;
+ Oid opno; /* PG_OPERATOR OID of the operator */
+ Oid opfuncid; /* PG_PROC OID of underlying function */
+ Oid opresulttype; /* PG_TYPE OID of result value */
+ bool opretset; /* true if operator returns set */
+ List *args; /* arguments to the operator (1 or 2) */
+ int location; /* token location, or -1 if unknown */
+} OpExpr;
+
+/*
+ * DistinctExpr - expression node for "x IS DISTINCT FROM y"
+ *
+ * Except for the nodetag, this is represented identically to an OpExpr
+ * 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 OpExpr DistinctExpr;
+
+/*
+ * ScalarArrayOpExpr - 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 because it must be boolean.
+ */
+typedef struct ScalarArrayOpExpr
+{
+ Expr xpr;
+ Oid opno; /* PG_OPERATOR OID of the operator */
+ Oid opfuncid; /* PG_PROC OID of underlying function */
+ bool useOr; /* true for ANY, false for ALL */
+ List *args; /* the scalar and array operands */
+ int location; /* token location, or -1 if unknown */
+} ScalarArrayOpExpr;
+
+/*
+ * BoolExpr - 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, the executor can
+ * handle any number of arguments. The parser generally treats AND and OR
+ * as binary and so it typically only produces two-element lists, but the
+ * optimizer will flatten trees of AND and OR nodes to produce longer lists
+ * when possible. There are also a few special cases where more arguments
+ * can appear before optimization.
+ */
+typedef enum BoolExprType
+{
+ AND_EXPR, OR_EXPR, NOT_EXPR
+} BoolExprType;
+
+typedef struct BoolExpr
+{
+ Expr xpr;
+ BoolExprType boolop;
+ List *args; /* arguments to this expression */
+ int location; /* token location, or -1 if unknown */
+} BoolExpr;
+
+/*
* SubLink
*
* A SubLink represents a subselect appearing in an expression, and in some
* EXISTS_SUBLINK EXISTS(SELECT ...)
* ALL_SUBLINK (lefthand) op ALL (SELECT ...)
* ANY_SUBLINK (lefthand) op ANY (SELECT ...)
- * MULTIEXPR_SUBLINK (lefthand) op (SELECT ...)
+ * ROWCOMPARE_SUBLINK (lefthand) op (SELECT ...)
* EXPR_SUBLINK (SELECT with single targetlist item ...)
- * For ALL, ANY, and MULTIEXPR, the lefthand is a list of expressions of the
- * same length as the subselect's targetlist. MULTIEXPR will *always* have
+ * ARRAY_SUBLINK ARRAY(SELECT with single targetlist item ...)
+ * 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 EXPR_SUBLINK instead (and any operator
* above the subselect will be represented separately). Note that both
- * MULTIEXPR and EXPR require the subselect to deliver only one row.
- * ALL, ANY, and MULTIEXPR require the combining operators to deliver boolean
- * results. These are reduced to one result per row using OR or AND semantics
- * depending on the "useor" flag. ALL and ANY combine the per-row results
- * using AND and OR semantics respectively.
- *
- * NOTE: lefthand and oper have varying meanings depending on where you look
- * in the parse/plan pipeline:
- * 1. gram.y delivers a list of the (untransformed) lefthand expressions in
- * lefthand, and sets oper to a single A_Expr (not a list!) containing
- * the string name of the operator, but no arguments.
- * 2. The parser's expression transformation transforms lefthand normally,
- * and replaces oper with a list of Oper nodes, one per lefthand
- * expression. These nodes represent the parser's resolution of exactly
- * which operator to apply to each pair of lefthand and targetlist
- * expressions. However, we have not constructed actual Expr trees for
- * these operators yet. This is the representation seen in saved rules
- * and in the rewriter.
- * 3. Finally, the planner converts the oper list to a list of normal Expr
- * nodes representing the application of the operator(s) to the lefthand
- * expressions and values from the inner targetlist. The inner
- * targetlist items are represented by placeholder Param or Const nodes.
- * The lefthand field is set to NIL, since its expressions are now in
- * the Expr list. This representation is passed to the executor.
- *
- * Planner routines that might see either representation 2 or 3 can tell
- * the difference by checking whether lefthand is NIL or not. Also,
- * representation 2 appears in a "bare" SubLink, while representation 3 is
- * found in SubLinks that are children of SubPlan nodes.
- *
- * In EXISTS and EXPR SubLinks, both lefthand and oper are unused and are
- * always NIL. useor is not significant either for these sublink types.
- * ----------------
+ * ROWCOMPARE and EXPR require the subselect to deliver only one row.
+ * 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.
+ *
+ * SubLink is classed as an Expr node, but it is not actually executable;
+ * it must be replaced in the expression tree by a SubPlan 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 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, and ARRAY SubLinks, testexpr and operName are unused and
+ * are always null.
+ *
+ * The CTE_SUBLINK case never occurs in actual SubLink nodes, but it is used
+ * in SubPlans generated for WITH subqueries.
*/
typedef enum SubLinkType
{
- EXISTS_SUBLINK, ALL_SUBLINK, ANY_SUBLINK, MULTIEXPR_SUBLINK, EXPR_SUBLINK
+ EXISTS_SUBLINK,
+ ALL_SUBLINK,
+ ANY_SUBLINK,
+ ROWCOMPARE_SUBLINK,
+ EXPR_SUBLINK,
+ ARRAY_SUBLINK,
+ CTE_SUBLINK /* for SubPlans only */
} SubLinkType;
typedef struct SubLink
{
- NodeTag type;
- SubLinkType subLinkType; /* EXISTS, ALL, ANY, MULTIEXPR, EXPR */
- bool useor; /* TRUE to combine column results with
- * "OR" not "AND" */
- List *lefthand; /* list of outer-query expressions on the
- * left */
- List *oper; /* list of Oper nodes for combining
- * operators */
+ Expr xpr;
+ SubLinkType subLinkType; /* see above */
+ Node *testexpr; /* outer-query test for ALL/ANY/ROWCOMPARE */
+ List *operName; /* originally specified operator name */
Node *subselect; /* subselect as Query* or parsetree */
+ int location; /* token location, or -1 if unknown */
} SubLink;
-/* ----------------
- * ArrayRef: describes an array subscripting operation
+/*
+ * SubPlan - executable expression node for a subplan (sub-SELECT)
*
- * An ArrayRef 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.
+ * The planner replaces SubLink nodes in expression trees with SubPlan
+ * nodes after it has finished planning the subquery. SubPlan 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.)
*
- * 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 an ordinary subplan, testexpr points to an executable expression
+ * (OpExpr, an AND/OR tree of OpExprs, or RowCompareExpr) for the combining
+ * operator(s); the left-hand arguments are the original lefthand expressions,
+ * and the right-hand arguments are PARAM_EXEC Param 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 SubLink node, but the PARAM_SUBLINK nodes are replaced by
+ * suitably numbered PARAM_EXEC nodes.
*
- * Note: array types can be fixed-length (refattrlength > 0), but only
- * when the element type is itself fixed-length. Otherwise they are
- * varlena structures and have refattrlength = -1. In any case,
- * an array type is never pass-by-value.
+ * 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 SubPlan
+ * node itself is not, but rather is found in the outer plan's initPlan
+ * list). In this case testexpr is NULL to avoid duplication.
*
- * Note: currently, refelemtype is NOT the element type, but the array type,
- * when doing subarray fetch or either type of store. It would be cleaner
- * to add more fields so we can distinguish the array element type from the
- * result type of the ArrayRef operator...
- * ----------------
+ * 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 PARAM_EXEC params indexed by parParam
+ * (the parParam and args lists must have the same ordering). setParam is a
+ * list of the 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 ArrayRef
+typedef struct SubPlan
{
- NodeTag type;
- int refattrlength; /* typlen of array type */
- int refelemlength; /* typlen of the array element type */
- Oid refelemtype; /* type of the result of the ArrayRef
- * operation */
- bool refelembyval; /* is the element type pass-by-value? */
- List *refupperindexpr;/* expressions that evaluate to upper
- * array indexes */
- List *reflowerindexpr;/* expressions that evaluate to lower
- * array indexes */
- Node *refexpr; /* the expression that evaluates to an
- * array value */
- Node *refassgnexpr; /* expression for the source value, or
- * NULL if fetch */
-} ArrayRef;
+ Expr xpr;
+ /* Fields copied from original SubLink: */
+ SubLinkType subLinkType; /* see above */
+ /* The combining operators, transformed to an executable expression: */
+ Node *testexpr; /* OpExpr or RowCompareExpr expression tree */
+ List *paramIds; /* IDs of Params embedded in the above */
+ /* Identification of the Plan tree to use: */
+ int plan_id; /* Index (from 1) in PlannedStmt.subplans */
+ /* Identification of the SubPlan for EXPLAIN and debugging purposes: */
+ char *plan_name; /* A name assigned during planning */
+ /* Extra data useful for determining subplan's output type: */
+ Oid firstColType; /* Type of first column of subplan result */
+ int32 firstColTypmod; /* Typmod 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 */
+ /* Information for passing params into and out of the subselect: */
+ /* setParam and parParam are lists of integers (param IDs) */
+ List *setParam; /* initplan subqueries have to set these
+ * Params for parent plan */
+ List *parParam; /* indices of input Params from parent plan */
+ List *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 */
+} SubPlan;
+
+/*
+ * AlternativeSubPlan - expression node for a choice among SubPlans
+ *
+ * The subplans are given as a List 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 AlternativeSubPlan
+{
+ Expr xpr;
+ List *subplans; /* SubPlan(s) with equivalent results */
+} AlternativeSubPlan;
/* ----------------
* FieldSelect
*
* FieldSelect represents the operation of extracting one field from a tuple
- * value. At runtime, the input expression is expected to yield a Datum
- * that contains a pointer-to-TupleTableSlot. The specified field number
- * is extracted and returned as a Datum.
+ * 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 FieldSelect
{
- NodeTag type;
- Node *arg; /* input expression */
+ Expr xpr;
+ Expr *arg; /* input expression */
AttrNumber fieldnum; /* attribute number of field to extract */
Oid resulttype; /* type of the field (result type of this
* node) */
int32 resulttypmod; /* output typmod (usually -1) */
} FieldSelect;
+/* ----------------
+ * FieldStore
+ *
+ * FieldStore 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 ArrayRef, this is used to implement UPDATE of a
+ * portion of a column.
+ *
+ * A single FieldStore 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 FieldStore
+{
+ Expr xpr;
+ Expr *arg; /* input tuple value */
+ List *newvals; /* new value(s) for field(s) */
+ List *fieldnums; /* integer list of field attnums */
+ Oid resulttype; /* type of result (same as type of arg) */
+ /* Like RowExpr, we deliberately omit a typmod here */
+} FieldStore;
+
/* ----------------
* RelabelType
*
typedef struct RelabelType
{
- NodeTag type;
- Node *arg; /* input expression */
+ Expr xpr;
+ Expr *arg; /* input expression */
Oid resulttype; /* output type of coercion expression */
int32 resulttypmod; /* output typmod (usually -1) */
+ CoercionForm relabelformat; /* how to display this node */
+ int location; /* token location, or -1 if unknown */
} RelabelType;
+/* ----------------
+ * CoerceViaIO
+ *
+ * CoerceViaIO 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 CoerceViaIO
+{
+ Expr xpr;
+ Expr *arg; /* input expression */
+ Oid resulttype; /* output type of coercion */
+ /* output typmod is not stored, but is presumed -1 */
+ CoercionForm coerceformat; /* how to display this node */
+ int location; /* token location, or -1 if unknown */
+} CoerceViaIO;
+
+/* ----------------
+ * ArrayCoerceExpr
+ *
+ * ArrayCoerceExpr 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 ArrayCoerceExpr
+{
+ Expr xpr;
+ Expr *arg; /* input expression (yields an array) */
+ Oid elemfuncid; /* OID of element coercion function, or 0 */
+ Oid resulttype; /* output type of coercion (an array type) */
+ int32 resulttypmod; /* output typmod (also element typmod) */
+ bool isExplicit; /* conversion semantics flag to pass to func */
+ CoercionForm coerceformat; /* how to display this node */
+ int location; /* token location, or -1 if unknown */
+} ArrayCoerceExpr;
+
+/* ----------------
+ * ConvertRowtypeExpr
+ *
+ * ConvertRowtypeExpr 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 ConvertRowtypeExpr
+{
+ Expr xpr;
+ Expr *arg; /* input expression */
+ Oid resulttype; /* output type (always a composite type) */
+ /* result typmod is not stored, but must be -1; see RowExpr comments */
+ CoercionForm convertformat; /* how to display this node */
+ int location; /* token location, or -1 if unknown */
+} ConvertRowtypeExpr;
+
+/*----------
+ * CaseExpr - 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
+ * CaseTestExpr '=' compexpr
+ * where the CaseTestExpr 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 CaseExpr has been through parse analysis
+ * yet by checking whether casetype is InvalidOid or not.
+ *----------
+ */
+typedef struct CaseExpr
+{
+ Expr xpr;
+ Oid casetype; /* type of expression result */
+ Expr *arg; /* implicit equality comparison argument */
+ List *args; /* the arguments (list of WHEN clauses) */
+ Expr *defresult; /* the default result (ELSE clause) */
+ int location; /* token location, or -1 if unknown */
+} CaseExpr;
+
+/*
+ * CaseWhen - one arm of a CASE expression
+ */
+typedef struct CaseWhen
+{
+ Expr xpr;
+ Expr *expr; /* condition expression */
+ Expr *result; /* substitution result */
+ int location; /* token location, or -1 if unknown */
+} CaseWhen;
+
+/*
+ * Placeholder node for the test value to be processed by a CASE expression.
+ * This is effectively like a Param, 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 CaseTestExpr
+{
+ Expr xpr;
+ Oid typeId; /* type for substituted value */
+ int32 typeMod; /* typemod for substituted value */
+} CaseTestExpr;
+
+/*
+ * ArrayExpr - 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 ArrayExpr
+{
+ Expr xpr;
+ Oid array_typeid; /* type of expression result */
+ Oid element_typeid; /* common type of array elements */
+ List *elements; /* the array elements or sub-arrays */
+ bool multidims; /* true if elements are sub-arrays */
+ int location; /* token location, or -1 if unknown */
+} ArrayExpr;
+
+/*
+ * RowExpr - 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 RowExpr 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 is NIL in a RowExpr built from an ordinary ROW() expression.
+ * It is provided in cases where we expand a whole-row Var into a RowExpr,
+ * to retain the column alias names of the RTE that the Var referenced
+ * (which would otherwise be very difficult to extract from the parsetree).
+ * Like the args list, it is one-for-one with physical fields of the rowtype.
+ */
+typedef struct RowExpr
+{
+ Expr xpr;
+ List *args; /* the fields */
+ Oid 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 RowExpr node.
+ */
+ CoercionForm row_format; /* how to display this node */
+ List *colnames; /* list of String, or NIL */
+ int location; /* token location, or -1 if unknown */
+} RowExpr;
+
+/*
+ * RowCompareExpr - 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 RowCompareExpr 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
+ * RowCompareType enum for the convenience of parser logic.
+ */
+typedef enum RowCompareType
+{
+ /* Values of this enum are chosen to match btree strategy numbers */
+ ROWCOMPARE_LT = 1, /* BTLessStrategyNumber */
+ ROWCOMPARE_LE = 2, /* BTLessEqualStrategyNumber */
+ ROWCOMPARE_EQ = 3, /* BTEqualStrategyNumber */
+ ROWCOMPARE_GE = 4, /* BTGreaterEqualStrategyNumber */
+ ROWCOMPARE_GT = 5, /* BTGreaterStrategyNumber */
+ ROWCOMPARE_NE = 6 /* no such btree strategy */
+} RowCompareType;
+
+typedef struct RowCompareExpr
+{
+ Expr xpr;
+ RowCompareType rctype; /* LT LE GE or GT, never EQ or NE */
+ List *opnos; /* OID list of pairwise comparison ops */
+ List *opfamilies; /* OID list of containing operator families */
+ List *largs; /* the left-hand input arguments */
+ List *rargs; /* the right-hand input arguments */
+} RowCompareExpr;
+
+/*
+ * CoalesceExpr - a COALESCE expression
+ */
+typedef struct CoalesceExpr
+{
+ Expr xpr;
+ Oid coalescetype; /* type of expression result */
+ List *args; /* the arguments */
+ int location; /* token location, or -1 if unknown */
+} CoalesceExpr;
+
+/*
+ * MinMaxExpr - a GREATEST or LEAST function
+ */
+typedef enum MinMaxOp
+{
+ IS_GREATEST,
+ IS_LEAST
+} MinMaxOp;
+
+typedef struct MinMaxExpr
+{
+ Expr xpr;
+ Oid minmaxtype; /* common type of arguments and result */
+ MinMaxOp op; /* function to execute */
+ List *args; /* the arguments */
+ int location; /* token location, or -1 if unknown */
+} MinMaxExpr;
+
+/*
+ * XmlExpr - various SQL/XML functions requiring special grammar productions
+ *
+ * 'name' carries the "NAME foo" argument (already XML-escaped).
+ * 'named_args' and 'arg_names' represent an xml_attribute list.
+ * 'args' carries all other arguments.
+ */
+typedef enum XmlExprOp
+{
+ IS_XMLCONCAT, /* XMLCONCAT(args) */
+ IS_XMLELEMENT, /* XMLELEMENT(name, xml_attributes, args) */
+ IS_XMLFOREST, /* XMLFOREST(xml_attributes) */
+ IS_XMLPARSE, /* XMLPARSE(text, is_doc, preserve_ws) */
+ IS_XMLPI, /* XMLPI(name [, args]) */
+ IS_XMLROOT, /* XMLROOT(xml, version, standalone) */
+ IS_XMLSERIALIZE, /* XMLSERIALIZE(is_document, xmlval) */
+ IS_DOCUMENT /* xmlval IS DOCUMENT */
+} XmlExprOp;
+
+typedef enum
+{
+ XMLOPTION_DOCUMENT,
+ XMLOPTION_CONTENT
+} XmlOptionType;
+
+typedef struct XmlExpr
+{
+ Expr xpr;
+ XmlExprOp op; /* xml function ID */
+ char *name; /* name in xml(NAME foo ...) syntaxes */
+ List *named_args; /* non-XML expressions for xml_attributes */
+ List *arg_names; /* parallel list of Value strings */
+ List *args; /* list of expressions */
+ XmlOptionType xmloption; /* DOCUMENT or CONTENT */
+ Oid type; /* target type for XMLSERIALIZE */
+ int32 typmod;
+ int location; /* token location, or -1 if unknown */
+} XmlExpr;
+
+/*
+ * NullIfExpr - a NULLIF expression
+ *
+ * Like DistinctExpr, this is represented the same as an OpExpr referencing
+ * the "=" operator for x and y.
+ */
+typedef OpExpr NullIfExpr;
+
+/* ----------------
+ * NullTest
+ *
+ * NullTest represents the operation of testing a value for NULLness.
+ * The appropriate test is performed and returned as a boolean Datum.
+ *
+ * NOTE: the semantics of this for rowtype inputs are noticeably different
+ * from the scalar case. It would probably be a good idea to include an
+ * "argisrow" flag in the struct to reflect that, but for the moment,
+ * we do not do so to avoid forcing an initdb during 8.2beta.
+ * ----------------
+ */
+
+typedef enum NullTestType
+{
+ IS_NULL, IS_NOT_NULL
+} NullTestType;
+
+typedef struct NullTest
+{
+ Expr xpr;
+ Expr *arg; /* input expression */
+ NullTestType nulltesttype; /* IS NULL, IS NOT NULL */
+} NullTest;
+
+/*
+ * BooleanTest
+ *
+ * BooleanTest 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 BoolTestType
+{
+ IS_TRUE, IS_NOT_TRUE, IS_FALSE, IS_NOT_FALSE, IS_UNKNOWN, IS_NOT_UNKNOWN
+} BoolTestType;
+
+typedef struct BooleanTest
+{
+ Expr xpr;
+ Expr *arg; /* input expression */
+ BoolTestType booltesttype; /* test type */
+} BooleanTest;
+
+/*
+ * CoerceToDomain
+ *
+ * CoerceToDomain 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
+ * RelabelType in the scenario where no constraints are applied.
+ */
+typedef struct CoerceToDomain
+{
+ Expr xpr;
+ Expr *arg; /* input expression */
+ Oid resulttype; /* domain type ID (result type) */
+ int32 resulttypmod; /* output typmod (currently always -1) */
+ CoercionForm coercionformat; /* how to display this node */
+ int location; /* token location, or -1 if unknown */
+} CoerceToDomain;
+
+/*
+ * Placeholder node for the value to be processed by a domain's check
+ * constraint. This is effectively like a Param, but can be implemented more
+ * simply since we need only one replacement value at a time.
+ *
+ * Note: the typeId/typeMod 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 CoerceToDomainValue
+{
+ Expr xpr;
+ Oid typeId; /* type for substituted value */
+ int32 typeMod; /* typemod for substituted value */
+ int location; /* token location, or -1 if unknown */
+} CoerceToDomainValue;
+
+/*
+ * 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 SetToDefault
+{
+ Expr xpr;
+ Oid typeId; /* type for substituted value */
+ int32 typeMod; /* typemod for substituted value */
+ int location; /* token location, or -1 if unknown */
+} SetToDefault;
+
+/*
+ * Node representing [WHERE] CURRENT OF cursor_name
+ *
+ * CURRENT OF is a bit like a Var, 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 CurrentOfExpr
+{
+ Expr xpr;
+ Index cvarno; /* RT index of target relation */
+ char *cursor_name; /* name of referenced cursor, or NULL */
+ int cursor_param; /* refcursor parameter number, or 0 */
+} CurrentOfExpr;
+
+/*--------------------
+ * TargetEntry -
+ * a target entry (used in query target lists)
+ *
+ * Strictly speaking, a TargetEntry 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 SortGroupClause 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 TargetEntry
+{
+ Expr xpr;
+ Expr *expr; /* expression to evaluate */
+ AttrNumber resno; /* attribute number (see notes above) */
+ char *resname; /* name of the column (could be NULL) */
+ Index ressortgroupref;/* nonzero if referenced by a sort/group
+ * clause */
+ Oid resorigtbl; /* OID of column's source table */
+ AttrNumber resorigcol; /* column's number in source table */
+ bool resjunk; /* set to true to eliminate the attribute from
+ * final target list */
+} TargetEntry;
+
/* ----------------------------------------------------------------
* node types for join trees
* or qualified join. Also, FromExpr nodes can appear to denote an
* ordinary cross-product join ("FROM foo, bar, baz WHERE ...").
* FromExpr is like a JoinExpr of jointype JOIN_INNER, except that it
- * may have any number of child nodes, not just two. Also, there is an
- * implementation-defined difference: the planner is allowed to join the
- * children of a FromExpr using whatever join order seems good to it.
- * At present, JoinExpr nodes are always joined in exactly the order
- * implied by the jointree structure (except the planner may choose to
- * swap inner and outer members of a join pair).
+ * 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.
* restricts visibility of the tables/columns inside it.
*
* During parse analysis, an RTE is created for the Join, 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.
+ * 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 JoinExpr
List *using; /* USING clause, if any (list of String) */
Node *quals; /* qualifiers on join, if any */
Alias *alias; /* user-written alias clause, if any */
- int rtindex; /* RT index assigned for join */
+ int rtindex; /* RT index assigned for join, or 0 */
} JoinExpr;
/*----------
projects / postgresql / blobdiff