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Re: Res: Finding all tables that have foreign keys referencing a table

From: Andreas Joseph Krogh <andreak(at)officenet(dot)no>
To: pgsql-sql(at)postgresql(dot)org
Cc: paulo matadr <saddoness(at)yahoo(dot)com(dot)br>
Subject: Re: Res: Finding all tables that have foreign keys referencing a table
Date: 2008-11-07 19:46:10
Message-ID: 200811072046.10358.andreak@officenet.no (view raw or flat)
Thread:
Lists: pgsql-sql
On Friday 07 November 2008 15:15:49 paulo matadr wrote:
> Try this
> 
> select table_schema, table_name
> from information_schema.columns
> where table_schema not in
> ('information_schema','pg_catalog')
> and column_name = '?'

AFAICS this lists all tables which have a column named '?', which is not what I'm after. I'm after listing all columns referencing a certain column as a FOREIGN KEY.

Example, making the FK's names "$1" to mimic old PG-behaviour, and proving my point about the FK-names not needing to be globaly unique:

CREATE TABLE test1(
id INTEGER PRIMARY KEY
);

CREATE TABLE test2(
id INTEGER PRIMARY KEY
);

CREATE TABLE test_ref1(
id INTEGER PRIMARY KEY,
entity_id INTEGER,
CONSTRAINT "$1" FOREIGN KEY (entity_id) REFERENCES test1(id)
);

CREATE TABLE test_ref2(
id INTEGER PRIMARY KEY,
entity_id INTEGER,
CONSTRAINT "$1" FOREIGN KEY (entity_id) REFERENCES test2(id)
);

andreak=# \d test_ref1
    Table "public.test_ref1"
  Column   |  Type   | Modifiers
-----------+---------+-----------
 id        | integer | not null
 entity_id | integer |
Indexes:
    "test_ref1_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
    "$1" FOREIGN KEY (entity_id) REFERENCES test1(id)

andreak=# \d test_ref2
    Table "public.test_ref2"
  Column   |  Type   | Modifiers
-----------+---------+-----------
 id        | integer | not null
 entity_id | integer |
Indexes:
    "test_ref2_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
    "$1" FOREIGN KEY (entity_id) REFERENCES test2(id)

andreak=#

Now, any idea about how to safely get all columns which reference test1.id?
-hackers; Any hints?

BTW:
andreak=# select version();
                                            version
-----------------------------------------------------------------------------------------------
 PostgreSQL 8.3.3 on i486-pc-linux-gnu, compiled by GCC cc (GCC) 4.2.3 (Ubuntu 4.2.3-2ubuntu7)

-- 
Andreas Joseph Krogh <andreak(at)officenet(dot)no>
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Subject: Re: Res: Finding all tables that have foreign keys referencing a table
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