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Code review for CREATE OR REPLACE VIEW patch. Do things in a saner order to

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result in hopefully-less-confusing error messages when the new definition
isn't compatible with the old; minor other cleanup.
This commit is contained in:
Tom Lane
2008-12-15 21:35:31 +00:00
parent 78b25fd2e9
commit 4da65a23e7
4 changed files with 56 additions and 46 deletions
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58
src/backend/commands/view.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.108 2008/12/06 23:22:46 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/view.c,v 1.109 2008/12/15 21:35:31 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -165,6 +165,9 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
/* Also check it's not in use already */
CheckTableNotInUse(rel, "CREATE OR REPLACE VIEW");
/*
* Due to the namespace visibility rules for temporary objects, we
* should only end up replacing a temporary view with another
@ -172,30 +175,6 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
*/
Assert(relation->istemp == rel->rd_istemp);
/*
* If new attributes have been added, we must modify the pre-existing
* view.
*/
if (list_length(attrList) > rel->rd_att->natts) {
List *atcmds = NIL;
ListCell *c;
int skip = rel->rd_att->natts;
foreach(c, attrList) {
AlterTableCmd *atcmd;
if (skip > 0) {
--skip;
continue;
}
atcmd = makeNode(AlterTableCmd);
atcmd->subtype = AT_AddColumnToView;
atcmd->def = lfirst(c);
atcmds = lappend(atcmds, atcmd);
}
AlterTableInternal(viewOid, atcmds, true);
}
/*
* Create a tuple descriptor to compare against the existing view, and
* verify that the old column list is an initial prefix of the new
@ -204,6 +183,34 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
descriptor = BuildDescForRelation(attrList);
checkViewTupleDesc(descriptor, rel->rd_att);
/*
* If new attributes have been added, we must add pg_attribute entries
* for them. It is convenient (although overkill) to use the ALTER
* TABLE ADD COLUMN infrastructure for this.
*/
if (list_length(attrList) > rel->rd_att->natts)
{
List *atcmds = NIL;
ListCell *c;
int skip = rel->rd_att->natts;
foreach(c, attrList)
{
AlterTableCmd *atcmd;
if (skip > 0)
{
skip--;
continue;
}
atcmd = makeNode(AlterTableCmd);
atcmd->subtype = AT_AddColumnToView;
atcmd->def = (Node *) lfirst(c);
atcmds = lappend(atcmds, atcmd);
}
AlterTableInternal(viewOid, atcmds, true);
}
/*
* Seems okay, so return the OID of the pre-existing view.
*/
@ -238,6 +245,7 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
* Verify that tupledesc associated with proposed new view definition
* matches tupledesc of old view. This is basically a cut-down version
* of equalTupleDescs(), with code added to generate specific complaints.
* Also, we allow the new tupledesc to have more columns than the old.
*/
static void
checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc)