Message-ID: <49E787FC.8020909@fmed.uba.ar>
Date: Thu, 16 Apr 2009 16:33:16 -0300
From: Gerardo Herzig <gherzig@fmed.uba.ar>
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To: pgsql-sql@postgresql.org
Subject: finding UNIQUES in information_schema
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Hi all. Im failing while trying to obtain some metainfo from
information_schema. Acording to the docs, constraint_column_usage and
key_column_usage views contains some information about constraints and
indexes.

See:
                       Table "public.almatnov"
   Column    |          Type          |           Modifiers
-------------+------------------------+--------------------------------
 formu       | integer                |
 alucod      | integer                | default 0
 codcarr     | character varying(3)   | default ''::character varying
 anifm       | character varying(2)   | default 20
 comentarios | text                   | default ''::text
Indexes:
    "almatnov_alucod_codcarr_idx" UNIQUE, btree (alucod, codcarr)
    "almatnov_codcarr_alucod" UNIQUE, btree (alucod, codcarr)


And now:
ematerias=# SELECT * from information_schema.constraint_table_usage
where table_name='almatnov';
 table_catalog | table_schema | table_name | constraint_catalog |
constraint_schema | constraint_name
---------------+--------------+------------+--------------------+-------------------+-----------------
(0 rows)

ematerias=# SELECT * from information_schema.key_column_usage where
table_name='almatnov';
 constraint_catalog | constraint_schema | constraint_name |
table_catalog | table_schema | table_name | column_name |
ordinal_position | position_in_unique_constraint
--------------------+-------------------+-----------------+---------------+--------------+------------+-------------+------------------+-------------------------------
(0 rows)

1) Im a doing anything wrong?
2) It is safe to extract metainfo from pg_catalog?

Thanks!

Gerardo