From: "Daniel Westermann (DWE)" <daniel.westermann@dbi-services.com>
To: "pgsql-docs@lists.postgresql.org" <pgsql-docs@lists.postgresql.org>
Subject: Wrong note in the information schema section?
Thread-Topic: Wrong note in the information schema section?
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Date: Mon, 30 Aug 2021 12:50:59 +0000
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Precedence: bulk

Hi %.=0A=
=0A=
we have this note in the information schema section, e.g. in https://www.po=
stgresql.org/docs/current/information-schema.html=0A=
=0A=
..."This is because the SQL standard requires constraint names to be unique=
 within a schema, but PostgreSQL does not enforce this restriction." =0A=
...=0A=
PostgreSQL does enforce unique constraint names in a schema:=0A=
=0A=
postgres=3D# create table t1 ( a int );=0A=
CREATE TABLE=0A=
postgres=3D# alter table t1 add constraint c1 unique (a);=0A=
ALTER TABLE=0A=
postgres=3D# alter table t1 add constraint c1 unique (a);=0A=
ERROR:  relation "c1" already exists=0A=
=0A=
Am I reading this wrong? I know you can have the same constraint with diffe=
rent names:=0A=
=0A=
postgres=3D# create table t1 ( a int );=0A=
CREATE TABLE=0A=
postgres=3D# alter table t1 add constraint c2 unique (a);=0A=
ALTER TABLE=0A=
postgres=3D# alter table t1 add constraint c3 unique (a);=0A=
ALTER TABLE=0A=
=0A=
... but I guess this is not what the notes is supposed to tell me, correct?=
=0A=
=0A=
Regards=0A=
Daniel=