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Code review for UPDATE tab SET col = DEFAULT patch ... whack it around

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so it has some chance of working in rules ...
This commit is contained in:
Tom Lane
2003-07-03 16:34:26 +00:00
parent 7b1885bf98
commit 455891bf96
15 changed files with 186 additions and 114 deletions
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65
src/backend/rewrite/rewriteHandler.c
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.121 2003/06/25 04:19:24 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.122 2003/07/03 16:34:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -250,7 +250,9 @@ adjustJoinTreeList(Query *parsetree, bool removert, int rt_index)
* attributes that have defaults and are not assigned to in the given tlist.
* (We do not insert anything for default-less attributes, however. The
* planner will later insert NULLs for them, but there's no reason to slow
* down rewriter processing with extra tlist nodes.)
* down rewriter processing with extra tlist nodes.) Also, for both INSERT
* and UPDATE, replace explicit DEFAULT specifications with column default
* expressions.
*
* 2. Merge multiple entries for the same target attribute, or declare error
* if we can't. Presently, multiple entries are only allowed for UPDATE of
@ -307,40 +309,49 @@ rewriteTargetList(Query *parsetree, Relation target_relation)
{
Assert(strcmp(resdom->resname,
NameStr(att_tup->attname)) == 0);
if (old_tle->expr != NULL && IsA(old_tle->expr, SetToDefault))
{
/* Set to the default value of the column, as requested */
Node *new_expr;
new_expr = build_column_default(target_relation, attrno);
new_tle = makeTargetEntry(makeResdom(attrno,
att_tup->atttypid,
att_tup->atttypmod,
pstrdup(NameStr(att_tup->attname)),
false),
(Expr *) new_expr);
}
else
/* Normal Case */
new_tle = process_matched_tle(old_tle, new_tle);
new_tle = process_matched_tle(old_tle, new_tle);
/* keep scanning to detect multiple assignments to attr */
}
}
if (new_tle == NULL && commandType == CMD_INSERT)
/*
* Handle the two cases where we need to insert a default expression:
* it's an INSERT and there's no tlist entry for the column, or the
* tlist entry is a DEFAULT placeholder node.
*/
if ((new_tle == NULL && commandType == CMD_INSERT) ||
(new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)))
{
/*
* Didn't find a matching tlist entry; if it's an INSERT, look
* for a default value, and add a tlist entry computing the
* default if we find one.
*/
Node *new_expr;
new_expr = build_column_default(target_relation, attrno);
/*
* If there is no default (ie, default is effectively NULL),
* we can omit the tlist entry in the INSERT case, since the
* planner can insert a NULL for itself, and there's no point
* in spending any more rewriter cycles on the entry. But in the
* UPDATE case we've got to explicitly set the column to NULL.
*/
if (!new_expr)
{
if (commandType == CMD_INSERT)
new_tle = NULL;
else
{
new_expr = (Node *) makeConst(att_tup->atttypid,
att_tup->attlen,
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
/* this is to catch a NOT NULL domain constraint */
new_expr = coerce_to_domain(new_expr,
InvalidOid,
att_tup->atttypid,
COERCE_IMPLICIT_CAST);
}
}
if (new_expr)
new_tle = makeTargetEntry(makeResdom(attrno,
att_tup->atttypid,