How to find child tables that inherit from another table in PSQL

Question

In PSQL, is there a good way of finding all the tables that inherit from another table? Ideally, I could get the data from a SQL query, but at this point, I'd be happy with any reliable method.

Eumenides

Answer 1

What do you mean "from sql query"? Does it mean SELECTing from pg_inherits is not good enough for you?

SELECT pg_inherits.*, c.relname AS child, p.relname AS parent
FROM
    pg_inherits JOIN pg_class AS c ON (inhrelid=c.oid)
    JOIN pg_class as p ON (inhparent=p.oid);

Rager

When I wrote "sql query", I meant something I could pass to PSQL on the command line, as opposed to something like \d that must be run interactively. So selecting from pg_inherits is a good start. Where can I find a table listing table names and their oids? – Eumenides

Das is perfekt! Vielen dank! – Eumenides

Watusimoto - \d can be passed to psql on the command line as well :) – Terrilynterrine

\d+ _parentTable_ will append a list all child tables from the command-line console – Hedonism

Answer 2

If you also need the schema names:

SELECT cn.nspname AS schema_child, c.relname AS child, pn.nspname AS schema_parent, p.relname AS parent
FROM pg_inherits 
JOIN pg_class AS c ON (inhrelid=c.oid)
JOIN pg_class as p ON (inhparent=p.oid)
JOIN pg_namespace pn ON pn.oid = p.relnamespace
JOIN pg_namespace cn ON cn.oid = c.relnamespace
WHERE p.relname = 'your table name' and pn.nspname = 'your schema name'

Clepsydra

Answer 3

If you want to find all child's from the master partition you can simply execute it like:

SELECT relname
FROM pg_class,pg_inherits
WHERE pg_class.oid=pg_inherits.inhrelid
AND inhparent
IN (SELECT oid FROM pg_class WHERE relname='your_master_partition')
ORDER BY relname;

Marylynnmarylynne