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Department of second thoughts: make checks for replacing a view slightly

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more flexible, and improve the error reporting.  Also, add documentation
for REPLACE RULE/VIEW.
This commit is contained in:
Tom Lane
2002-09-02 20:04:40 +00:00
parent b4d24d78a9
commit 8f60f43f2e
5 changed files with 84 additions and 24 deletions
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53
src/backend/commands/view.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.69 2002/09/02 02:13:01 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.70 2002/09/02 20:04:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -29,6 +29,9 @@
#include "utils/lsyscache.h"
static void checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc);
/*---------------------------------------------------------------------
* DefineVirtualRelation
*
@ -111,15 +114,9 @@ DefineVirtualRelation(const RangeVar *relation, List *tlist, bool replace)
/*
* Create a tuple descriptor to compare against the existing view,
* and verify it matches.
*
* XXX the error message is a bit cheesy here: would be useful to
* give a more specific complaint about the difference in the
* descriptors. No time for it at the moment though.
*/
descriptor = BuildDescForRelation(attrList);
if (!equalTupleDescs(descriptor, rel->rd_att))
elog(ERROR, "Cannot change column set of existing view %s",
RelationGetRelationName(rel));
checkViewTupleDesc(descriptor, rel->rd_att);
/*
* Seems okay, so return the OID of the pre-existing view.
@ -149,6 +146,46 @@ 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.
*/
static void
checkViewTupleDesc(TupleDesc newdesc, TupleDesc olddesc)
{
int i;
if (newdesc->natts != olddesc->natts)
elog(ERROR, "Cannot change number of columns in view");
/* we can ignore tdhasoid */
for (i = 0; i < newdesc->natts; i++)
{
Form_pg_attribute newattr = newdesc->attrs[i];
Form_pg_attribute oldattr = olddesc->attrs[i];
/* XXX not right, but we don't support DROP COL on view anyway */
if (newattr->attisdropped != oldattr->attisdropped)
elog(ERROR, "Cannot change number of columns in view");
if (strcmp(NameStr(newattr->attname), NameStr(oldattr->attname)) != 0)
elog(ERROR, "Cannot change name of view column \"%s\"",
NameStr(oldattr->attname));
/* XXX would it be safe to allow atttypmod to change? Not sure */
if (newattr->atttypid != oldattr->atttypid ||
newattr->atttypmod != oldattr->atttypmod)
elog(ERROR, "Cannot change datatype of view column \"%s\"",
NameStr(oldattr->attname));
/* We can ignore the remaining attributes of an attribute... */
}
/*
* We ignore the constraint fields. The new view desc can't have any
* constraints, and the only ones that could be on the old view are
* defaults, which we are happy to leave in place.
*/
}
static RuleStmt *
FormViewRetrieveRule(const RangeVar *view, Query *viewParse, bool replace)
{