From e07ae21f7ec2260c17136a7afaa4dbca405d9c24 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Sat, 19 Feb 2011 18:21:03 -0500
Subject: [PATCH] Document that an SQL-standard-compliant query that expects a
unique row from information_schema.referential_constraints might return
several in Postgres because we allow duplicate-named constraints in the same
schema.
---
doc/src/sgml/information_schema.sgml | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index 52407a741fe..91c2dd4d525 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -3211,6 +3211,19 @@ ORDER BY c.ordinal_position;
</tbody>
</tgroup>
</table>
+
+ <note>
+ <para>
+ The SQL standard requires constraint names to be unique within a
+ schema; <productname>PostgreSQL</productname>, however, does not
+ enforce this restriction. If duplicate-named constraints are
+ stored in the same <productname>PostgreSQL</productname> schema, a
+ standard-compliant query that expects to return one row might
+ return several, one for each matching constraint stored in the
+ specified schema.
+ </para>
+ </note>
+
</sect1>
<sect1 id="infoschema-role-column-grants">
--
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