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Improve error message for the case where a requested foreign key constraint

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does match some unique index on the referenced table, but that index is
only deferrably unique.  We were doing this nicely for the
default-to-primary-key case, but were being lazy for the other case.

Dean Rasheed
This commit is contained in:
Tom Lane 2009-08-12 23:00:12 +00:00
parent 5d3e2324a6
commit b6bde524af
1 changed files with 32 additions and 9 deletions
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41
src/backend/commands/tablecmds.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.296 2009/08/07 15:27:56 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.297 2009/08/12 23:00:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -5117,6 +5117,7 @@ transformFkeyCheckAttrs(Relation pkrel,
{
Oid indexoid = InvalidOid;
bool found = false;
bool found_deferrable = false;
List *indexoidlist;
ListCell *indexoidscan;
@ -5143,12 +5144,11 @@ transformFkeyCheckAttrs(Relation pkrel,
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
/*
* Must have the right number of columns; must be unique (non
* deferrable) and not a partial index; forget it if there are any
* expressions, too
* Must have the right number of columns; must be unique and not a
* partial index; forget it if there are any expressions, too
*/
if (indexStruct->indnatts == numattrs &&
indexStruct->indisunique && indexStruct->indimmediate &&
indexStruct->indisunique &&
heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
heap_attisnull(indexTuple, Anum_pg_index_indexprs))
{
@ -5198,6 +5198,21 @@ transformFkeyCheckAttrs(Relation pkrel,
break;
}
}
/*
* Refuse to use a deferrable unique/primary key. This is per
* SQL spec, and there would be a lot of interesting semantic
* problems if we tried to allow it.
*/
if (found && !indexStruct->indimmediate)
{
/*
* Remember that we found an otherwise matching index, so
* that we can generate a more appropriate error message.
*/
found_deferrable = true;
found = false;
}
}
ReleaseSysCache(indexTuple);
if (found)
@ -5205,10 +5220,18 @@ transformFkeyCheckAttrs(Relation pkrel,
}
if (!found)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FOREIGN_KEY),
errmsg("there is no unique constraint matching given keys for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
{
if (found_deferrable)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("cannot use a deferrable unique constraint for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_FOREIGN_KEY),
errmsg("there is no unique constraint matching given keys for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
}
list_free(indexoidlist);