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Phase 2 of read-only-plans project: restructure expression-tree nodes
so that all executable expression nodes inherit from a common supertype Expr. This is somewhat of an exercise in code purity rather than any real functional advance, but getting rid of the extra Oper or Func node formerly used in each operator or function call should provide at least a little space and speed improvement. initdb forced by changes in stored-rules representation.
This commit is contained in:
Tom Lane
@@ -10,7 +10,7 @@
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: primnodes.h,v 1.71 2002/11/30 21:25:06 tgl Exp $
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* $Id: primnodes.h,v 1.72 2002/12/12 15:49:40 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@@ -67,31 +67,6 @@ typedef struct Resdom
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* from final target list */
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} Resdom;
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/*
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* Fjoin
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*/
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typedef struct Fjoin
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{
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NodeTag type;
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bool fj_initialized; /* true if the Fjoin has already been
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* initialized for the current target list
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* evaluation */
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int fj_nNodes; /* The number of Iter nodes returning sets
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* that the node will flatten */
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List *fj_innerNode; /* exactly one Iter node. We eval every
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* node in the outerList once then eval
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* the inner node to completion pair the
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* outerList result vector with each inner
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* result to form the full result. When
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* the inner has been exhausted, we get
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* the next outer result vector and reset
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* the inner. */
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DatumPtr fj_results; /* The complete (flattened) result vector */
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BoolPtr fj_alwaysDone; /* a null vector to indicate sets with a
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* cardinality of 0, we treat them as the
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* set {NULL}. */
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} Fjoin;
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/*
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* Alias -
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@@ -140,96 +115,20 @@ typedef struct RangeVar
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*/
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/*
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* CoercionContext - distinguishes the allowed set of type casts
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* Expr - generic superclass for executable-expression nodes
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*
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* NB: ordering of the alternatives is significant; later (larger) values
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* allow more casts than earlier ones.
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* All node types that are used in executable expression trees should derive
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* from Expr (that is, have Expr as their first field). Since Expr only
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* contains NodeTag, this is a formality, but it is an easy form of
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* documentation. See also the ExprState node types in execnodes.h.
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*/
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typedef enum CoercionContext
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{
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COERCION_IMPLICIT, /* coercion in context of expression */
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COERCION_ASSIGNMENT, /* coercion in context of assignment */
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COERCION_EXPLICIT /* explicit cast operation */
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} CoercionContext;
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/*
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* CoercionForm - information showing how to display a function-call node
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*/
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typedef enum CoercionForm
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{
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COERCE_EXPLICIT_CALL, /* display as a function call */
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COERCE_EXPLICIT_CAST, /* display as an explicit cast */
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COERCE_IMPLICIT_CAST, /* implicit cast, so hide it */
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COERCE_DONTCARE /* special case for pathkeys */
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} CoercionForm;
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/*
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* Expr
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*
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* Note: DISTINCT_EXPR implements the "x IS DISTINCT FROM y" construct.
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* This is similar to an OP_EXPR, except for its handling of NULL inputs.
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* The oper field is always an Oper node for the "=" operator for x and y.
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* (We use "=", not the more obvious "<>", because more datatypes have "="
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* than "<>". This means the executor must invert the operator result.)
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*/
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typedef enum OpType
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{
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OP_EXPR, DISTINCT_EXPR, FUNC_EXPR,
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OR_EXPR, AND_EXPR, NOT_EXPR, SUBPLAN_EXPR
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} OpType;
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typedef struct Expr
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{
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NodeTag type;
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Oid typeOid; /* oid of the type of this expression */
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OpType opType; /* kind of expression */
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Node *oper; /* operator node if needed (Oper, Func, or
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* SubPlan) */
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List *args; /* arguments to this expression */
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} Expr;
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/*
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* Oper - Expr subnode for an OP_EXPR (or DISTINCT_EXPR)
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*
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* NOTE: in the good old days 'opno' used to be both (or either, or
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* neither) the pg_operator oid, and/or the pg_proc oid depending
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* on the postgres module in question (parser->pg_operator,
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* executor->pg_proc, planner->both), the mood of the programmer,
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* and the phase of the moon (rumors that it was also depending on the day
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* of the week are probably false). To make things even more postgres-like
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* (i.e. a mess) some comments were referring to 'opno' using the name
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* 'opid'. Anyway, now we have two separate fields, and of course that
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* immediately removes all bugs from the code... [ sp :-) ].
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*
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* Note also that opid is not necessarily filled in immediately on creation
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* of the node. The planner makes sure it is valid before passing the node
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* tree to the executor, but during parsing/planning opid is typically 0.
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*/
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typedef struct Oper
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{
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NodeTag type;
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Oid opno; /* PG_OPERATOR OID of the operator */
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Oid opid; /* PG_PROC OID of underlying function */
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Oid opresulttype; /* PG_TYPE OID of result value */
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bool opretset; /* true if operator returns set */
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FunctionCachePtr op_fcache; /* runtime state, else NULL */
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} Oper;
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/*
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* Func - Expr subnode for a FUNC_EXPR
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*/
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typedef struct Func
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{
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NodeTag type;
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Oid funcid; /* PG_PROC OID of the function */
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Oid funcresulttype; /* PG_TYPE OID of result value */
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bool funcretset; /* true if function returns set */
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CoercionForm funcformat; /* how to display this function call */
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FunctionCachePtr func_fcache; /* runtime state, or NULL */
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} Func;
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/*
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* Var
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* Var - expression node representing a variable (ie, a table column)
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*
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* Note: during parsing/planning, varnoold/varoattno are always just copies
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* of varno/varattno. At the tail end of planning, Var nodes appearing in
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@@ -248,7 +147,7 @@ typedef struct Func
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typedef struct Var
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{
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NodeTag type;
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Expr xpr;
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Index varno; /* index of this var's relation in the
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* range table (could also be INNER or
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* OUTER) */
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@@ -272,7 +171,7 @@ typedef struct Var
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*/
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typedef struct Const
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{
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NodeTag type;
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Expr xpr;
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Oid consttype; /* PG_TYPE OID of the constant's datatype */
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int constlen; /* typlen of the constant's datatype */
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Datum constvalue; /* the constant's value */
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@@ -300,12 +199,11 @@ typedef struct Const
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*
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* PARAM_EXEC: The parameter is an internal executor parameter.
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* It has a number contained in the `paramid' field.
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*
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* ----------------
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*/
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typedef struct Param
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{
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NodeTag type;
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Expr xpr;
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int paramkind; /* kind of parameter. See above */
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AttrNumber paramid; /* numeric ID for parameter ("$1") */
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char *paramname; /* name for parameter ("$.foo") */
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@@ -317,84 +215,17 @@ typedef struct Param
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*/
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typedef struct Aggref
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{
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NodeTag type;
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Expr xpr;
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Oid aggfnoid; /* pg_proc Oid of the aggregate */
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Oid aggtype; /* type Oid of result of the aggregate */
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Node *target; /* expression we are aggregating on */
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Expr *target; /* expression we are aggregating on */
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bool aggstar; /* TRUE if argument was really '*' */
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bool aggdistinct; /* TRUE if it's agg(DISTINCT ...) */
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/* XXX this should move to AggrefExprState: */
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int aggno; /* workspace for executor (see nodeAgg.c) */
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} Aggref;
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/* ----------------
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* SubLink
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*
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* A SubLink represents a subselect appearing in an expression, and in some
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* cases also the combining operator(s) just above it. The subLinkType
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* indicates the form of the expression represented:
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* EXISTS_SUBLINK EXISTS(SELECT ...)
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* ALL_SUBLINK (lefthand) op ALL (SELECT ...)
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* ANY_SUBLINK (lefthand) op ANY (SELECT ...)
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* MULTIEXPR_SUBLINK (lefthand) op (SELECT ...)
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* EXPR_SUBLINK (SELECT with single targetlist item ...)
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* For ALL, ANY, and MULTIEXPR, the lefthand is a list of expressions of the
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* same length as the subselect's targetlist. MULTIEXPR will *always* have
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* a list with more than one entry; if the subselect has just one target
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* then the parser will create an EXPR_SUBLINK instead (and any operator
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* above the subselect will be represented separately). Note that both
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* MULTIEXPR and EXPR require the subselect to deliver only one row.
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* ALL, ANY, and MULTIEXPR require the combining operators to deliver boolean
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* results. These are reduced to one result per row using OR or AND semantics
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* depending on the "useor" flag. ALL and ANY combine the per-row results
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* using AND and OR semantics respectively.
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*
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* NOTE: lefthand and oper have varying meanings depending on where you look
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* in the parse/plan pipeline:
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* 1. gram.y delivers a list of the (untransformed) lefthand expressions in
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* lefthand, and sets oper to a single A_Expr (not a list!) containing
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* the string name of the operator, but no arguments.
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* 2. The parser's expression transformation transforms lefthand normally,
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* and replaces oper with a list of Oper nodes, one per lefthand
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* expression. These nodes represent the parser's resolution of exactly
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* which operator to apply to each pair of lefthand and targetlist
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* expressions. However, we have not constructed actual Expr trees for
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* these operators yet. This is the representation seen in saved rules
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* and in the rewriter.
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* 3. Finally, the planner converts the oper list to a list of normal Expr
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* nodes representing the application of the operator(s) to the lefthand
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* expressions and values from the inner targetlist. The inner
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* targetlist items are represented by placeholder Param nodes.
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* The lefthand field is set to NIL, since its expressions are now in
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* the Expr list. This representation is passed to the executor.
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*
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* Planner routines that might see either representation 2 or 3 can tell
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* the difference by checking whether lefthand is NIL or not. Also,
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* representation 2 appears in a "bare" SubLink, while representation 3 is
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* found in SubLinks that are children of SubPlan nodes.
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*
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* In EXISTS and EXPR SubLinks, both lefthand and oper are unused and are
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* always NIL. useor is not significant either for these sublink types.
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* ----------------
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*/
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typedef enum SubLinkType
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{
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EXISTS_SUBLINK, ALL_SUBLINK, ANY_SUBLINK, MULTIEXPR_SUBLINK, EXPR_SUBLINK
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} SubLinkType;
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typedef struct SubLink
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{
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NodeTag type;
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SubLinkType subLinkType; /* EXISTS, ALL, ANY, MULTIEXPR, EXPR */
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bool useor; /* TRUE to combine column results with
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* "OR" not "AND" */
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List *lefthand; /* list of outer-query expressions on the
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* left */
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List *oper; /* list of Oper nodes for combining
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* operators */
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Node *subselect; /* subselect as Query* or parsetree */
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} SubLink;
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/* ----------------
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* ArrayRef: describes an array subscripting operation
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*
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@@ -424,7 +255,7 @@ typedef struct SubLink
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*/
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typedef struct ArrayRef
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{
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NodeTag type;
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Expr xpr;
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Oid refrestype; /* type of the result of the ArrayRef
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* operation */
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int refattrlength; /* typlen of array type */
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@@ -435,12 +266,207 @@ typedef struct ArrayRef
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* array indexes */
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List *reflowerindexpr;/* expressions that evaluate to lower
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* array indexes */
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Node *refexpr; /* the expression that evaluates to an
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Expr *refexpr; /* the expression that evaluates to an
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* array value */
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Node *refassgnexpr; /* expression for the source value, or
|
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Expr *refassgnexpr; /* expression for the source value, or
|
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* NULL if fetch */
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} ArrayRef;
|
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|
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/*
|
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* CoercionContext - distinguishes the allowed set of type casts
|
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*
|
||||
* 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;
|
||||
|
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/*
|
||||
* 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 pathkeys */
|
||||
} 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 */
|
||||
|
||||
FunctionCachePtr func_fcache; /* XXX runtime state, or NULL */
|
||||
} 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 is typically 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) */
|
||||
|
||||
FunctionCachePtr op_fcache; /* XXX runtime state, else NULL */
|
||||
} 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;
|
||||
|
||||
/*
|
||||
* 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 treats AND and OR as binary
|
||||
* and so it only produces two-element lists, but the optimizer will flatten
|
||||
* trees of AND and OR nodes to produce longer lists when possible.
|
||||
*/
|
||||
typedef enum BoolExprType
|
||||
{
|
||||
AND_EXPR, OR_EXPR, NOT_EXPR
|
||||
} BoolExprType;
|
||||
|
||||
typedef struct BoolExpr
|
||||
{
|
||||
Expr xpr;
|
||||
BoolExprType boolop;
|
||||
List *args; /* arguments to this expression */
|
||||
} BoolExpr;
|
||||
|
||||
/* ----------------
|
||||
* SubLink
|
||||
*
|
||||
* A SubLink 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:
|
||||
* EXISTS_SUBLINK EXISTS(SELECT ...)
|
||||
* ALL_SUBLINK (lefthand) op ALL (SELECT ...)
|
||||
* ANY_SUBLINK (lefthand) op ANY (SELECT ...)
|
||||
* MULTIEXPR_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
|
||||
* 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.
|
||||
*
|
||||
* SubLink is classed as an Expr node, but it is not actually executable;
|
||||
* it must be replaced in the expression tree by a SubPlanExpr node during
|
||||
* planning.
|
||||
*
|
||||
* 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 OpExpr 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 complete Expr trees for
|
||||
* these operations yet: the args fields of the OpExpr nodes are NIL.
|
||||
* 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 OpExpr
|
||||
* 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 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 SubPlanExpr 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.
|
||||
* ----------------
|
||||
*/
|
||||
typedef enum SubLinkType
|
||||
{
|
||||
EXISTS_SUBLINK, ALL_SUBLINK, ANY_SUBLINK, MULTIEXPR_SUBLINK, EXPR_SUBLINK
|
||||
} SubLinkType;
|
||||
|
||||
|
||||
typedef struct SubLink
|
||||
{
|
||||
Expr xpr;
|
||||
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 OpExpr nodes for combining
|
||||
* operators, or final list of executable
|
||||
* expressions */
|
||||
Node *subselect; /* subselect as Query* or parsetree */
|
||||
} SubLink;
|
||||
|
||||
/*
|
||||
* SubPlanExpr - executable expression node for a subplan (sub-SELECT)
|
||||
*
|
||||
* The planner replaces SubLink nodes in expression trees with SubPlanExpr
|
||||
* nodes after it has finished planning the subquery. See notes above.
|
||||
*/
|
||||
typedef struct SubPlanExpr
|
||||
{
|
||||
Expr xpr;
|
||||
Oid typeOid; /* PG_TYPE OID of the expression result */
|
||||
struct Plan *plan; /* subselect plan itself */
|
||||
int plan_id; /* dummy thing because of we haven't equal
|
||||
* funcs for plan nodes... actually, we
|
||||
* could put *plan itself somewhere else
|
||||
* (TopPlan node ?)... */
|
||||
List *rtable; /* range table for subselect */
|
||||
/* setParam and parParam are lists of integers (param IDs) */
|
||||
List *setParam; /* non-correlated EXPR & EXISTS subqueries
|
||||
* have to set some Params for paren Plan */
|
||||
List *parParam; /* indices of input Params from parent plan */
|
||||
List *args; /* exprs to pass as parParam values */
|
||||
SubLink *sublink; /* SubLink node from parser; holds info
|
||||
* about what to do with subselect's
|
||||
* results */
|
||||
|
||||
struct SubPlanState *pstate; /* XXX TEMPORARY HACK */
|
||||
} SubPlanExpr;
|
||||
|
||||
/* ----------------
|
||||
* FieldSelect
|
||||
*
|
||||
@@ -453,8 +479,8 @@ typedef struct ArrayRef
|
||||
|
||||
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) */
|
||||
@@ -476,13 +502,134 @@ typedef struct FieldSelect
|
||||
|
||||
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 */
|
||||
} RelabelType;
|
||||
|
||||
/*
|
||||
* CaseExpr - a CASE expression
|
||||
*/
|
||||
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) */
|
||||
} CaseExpr;
|
||||
|
||||
/*
|
||||
* CaseWhen - an argument to a CASE expression
|
||||
*/
|
||||
typedef struct CaseWhen
|
||||
{
|
||||
Expr xpr;
|
||||
Expr *expr; /* condition expression */
|
||||
Expr *result; /* substitution result */
|
||||
} CaseWhen;
|
||||
|
||||
/* ----------------
|
||||
* NullTest
|
||||
*
|
||||
* NullTest represents the operation of testing a value for NULLness.
|
||||
* Currently, we only support scalar input values, but eventually a
|
||||
* row-constructor input should be supported.
|
||||
* The appropriate test is performed and returned as a boolean Datum.
|
||||
* ----------------
|
||||
*/
|
||||
|
||||
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;
|
||||
|
||||
/*
|
||||
* ConstraintTest
|
||||
*
|
||||
* ConstraintTest represents the operation of testing a value to see whether
|
||||
* it meets a constraint. If so, the input value is returned as the result;
|
||||
* if not, an error is raised.
|
||||
*/
|
||||
|
||||
typedef enum ConstraintTestType
|
||||
{
|
||||
CONSTR_TEST_NOTNULL,
|
||||
CONSTR_TEST_CHECK
|
||||
} ConstraintTestType;
|
||||
|
||||
typedef struct ConstraintTest
|
||||
{
|
||||
Expr xpr;
|
||||
Expr *arg; /* input expression */
|
||||
ConstraintTestType testtype; /* test type */
|
||||
char *name; /* name of constraint (for error msgs) */
|
||||
char *domname; /* name of domain (for error messages) */
|
||||
Expr *check_expr; /* for CHECK test, a boolean expression */
|
||||
} ConstraintTest;
|
||||
|
||||
/*
|
||||
* Placeholder node for the value to be processed by a domains
|
||||
* check constraint. This is effectively like a Param; could we use
|
||||
* a Param node instead?
|
||||
*/
|
||||
typedef struct ConstraintTestValue
|
||||
{
|
||||
Expr xpr;
|
||||
Oid typeId;
|
||||
int32 typeMod;
|
||||
} ConstraintTestValue;
|
||||
|
||||
|
||||
/*
|
||||
* 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.
|
||||
*
|
||||
* The separation between TargetEntry and Resdom is historical. One of these
|
||||
* days, Resdom should probably get folded into TargetEntry.
|
||||
*/
|
||||
typedef struct TargetEntry
|
||||
{
|
||||
Expr xpr;
|
||||
Resdom *resdom; /* descriptor for targetlist item */
|
||||
Expr *expr; /* expression to evaluate */
|
||||
} TargetEntry;
|
||||
|
||||
|
||||
/* ----------------------------------------------------------------
|
||||
* node types for join trees
|
||||
|
||||
Reference in New Issue
Block a user