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Promote row expressions to full-fledged citizens of the expression syntax,

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rather than allowing them only in a few special cases as before.  In
particular you can now pass a ROW() construct to a function that accepts
a rowtype parameter.  Internal generation of RowExprs fixes a number of
corner cases that used to not work very well, such as referencing the
whole-row result of a JOIN or subquery.  This represents a further step in
the work I started a month or so back to make rowtype values into
first-class citizens.
This commit is contained in:
Tom Lane
2004-05-10 22:44:49 +00:00
parent 9a939886ac
commit 2f63232d30
34 changed files with 1281 additions and 551 deletions
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5
src/backend/rewrite/rewriteHandler.c
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.134 2004/04/01 21:28:44 tgl Exp $
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.135 2004/05/10 22:44:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -212,6 +212,8 @@ rewriteRuleAction(Query *parsetree,
sub_action = (Query *) ResolveNew((Node *) sub_action,
new_varno,
0,
rt_fetch(new_varno,
sub_action->rtable),
parsetree->targetList,
event,
current_varno);
@@ -947,6 +949,7 @@ CopyAndAddInvertedQual(Query *parsetree,
new_qual = ResolveNew(new_qual,
PRS2_NEW_VARNO,
0,
rt_fetch(rt_index, parsetree->rtable),
parsetree->targetList,
event,
rt_index);

114
src/backend/rewrite/rewriteManip.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.81 2003/11/29 19:51:55 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.82 2004/05/10 22:44:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -850,6 +850,10 @@ AddInvertedQual(Query *parsetree, Node *qual)
* If not, we either change the unmatched Var's varno to update_varno
* (when event == CMD_UPDATE) or replace it with a constant NULL.
*
* The caller must also provide target_rte, the RTE describing the target
* relation. This is needed to handle whole-row Vars referencing the target.
* We expand such Vars into RowExpr constructs.
*
* Note: the business with inserted_sublink is needed to update hasSubLinks
* in subqueries when the replacement adds a subquery inside a subquery.
* Messy, isn't it? We do not need to do similar pushups for hasAggs,
@@ -861,12 +865,52 @@ typedef struct
{
int target_varno;
int sublevels_up;
RangeTblEntry *target_rte;
List *targetlist;
int event;
int update_varno;
bool inserted_sublink;
} ResolveNew_context;
static Node *
resolve_one_var(Var *var, ResolveNew_context *context)
{
TargetEntry *tle;
tle = get_tle_by_resno(context->targetlist, var->varattno);
if (tle == NULL)
{
/* Failed to find column in insert/update tlist */
if (context->event == CMD_UPDATE)
{
/* For update, just change unmatched var's varno */
var = (Var *) copyObject(var);
var->varno = context->update_varno;
var->varnoold = context->update_varno;
return (Node *) var;
}
else
{
/* Otherwise replace unmatched var with a null */
return (Node *) makeNullConst(var->vartype);
}
}
else
{
/* Make a copy of the tlist item to return */
Node *n = copyObject(tle->expr);
/* Adjust varlevelsup if tlist item is from higher query */
if (var->varlevelsup > 0)
IncrementVarSublevelsUp(n, var->varlevelsup, 0);
/* Report it if we are adding a sublink to query */
if (!context->inserted_sublink)
context->inserted_sublink = checkExprHasSubLink(n);
return n;
}
}
static Node *
ResolveNew_mutator(Node *node, ResolveNew_context *context)
{
@@ -881,45 +925,41 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
if (this_varno == context->target_varno &&
this_varlevelsup == context->sublevels_up)
{
TargetEntry *tle;
/* band-aid: don't do the wrong thing with a whole-tuple Var */
if (var->varattno == InvalidAttrNumber)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot handle whole-row reference")));
tle = get_tle_by_resno(context->targetlist, var->varattno);
if (tle == NULL)
{
if (context->event == CMD_UPDATE)
{
/* For update, just change unmatched var's varno */
var = (Var *) copyObject(node);
var->varno = context->update_varno;
var->varnoold = context->update_varno;
return (Node *) var;
}
else
{
/* Otherwise replace unmatched var with a null */
return (Node *) makeNullConst(var->vartype);
}
}
else
{
/* Make a copy of the tlist item to return */
Node *n = copyObject(tle->expr);
/* Must expand whole-tuple reference into RowExpr */
RangeTblEntry *rte = context->target_rte;
RowExpr *rowexpr;
List *fields = NIL;
AttrNumber nfields = length(rte->eref->colnames);
AttrNumber nf;
/* Adjust varlevelsup if tlist item is from higher query */
if (this_varlevelsup > 0)
IncrementVarSublevelsUp(n, this_varlevelsup, 0);
/* Report it if we are adding a sublink to query */
if (!context->inserted_sublink)
context->inserted_sublink = checkExprHasSubLink(n);
return n;
for (nf = 1; nf <= nfields; nf++)
{
Oid vartype;
int32 vartypmod;
Var *newvar;
get_rte_attribute_type(rte, nf, &vartype, &vartypmod);
newvar = makeVar(this_varno,
nf,
vartype,
vartypmod,
this_varlevelsup);
fields = lappend(fields,
resolve_one_var(newvar, context));
}
rowexpr = makeNode(RowExpr);
rowexpr->args = fields;
rowexpr->row_typeid = var->vartype;
rowexpr->row_format = COERCE_IMPLICIT_CAST;
return (Node *) rowexpr;
}
/* Normal case for scalar variable */
return resolve_one_var(var, context);
}
/* otherwise fall through to copy the var normally */
}
@@ -948,12 +988,14 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
Node *
ResolveNew(Node *node, int target_varno, int sublevels_up,
RangeTblEntry *target_rte,
List *targetlist, int event, int update_varno)
{
ResolveNew_context context;
context.target_varno = target_varno;
context.sublevels_up = sublevels_up;
context.target_rte = target_rte;
context.targetlist = targetlist;
context.event = event;
context.update_varno = update_varno;