PostgreSQL: SQL script to get a list of all tables that has a particular column as foreign key

Question

I'm using PostgreSQL and I'm trying to list all the tables that have a particular column from a table as a foreign-key/reference. Can this be done? I'm sure this information is stored somewhere in information_schema but I have no idea how to start querying it.

Answer 1

select R.TABLE_NAME
from INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE u
inner join INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS FK
    on U.CONSTRAINT_CATALOG = FK.UNIQUE_CONSTRAINT_CATALOG
    and U.CONSTRAINT_SCHEMA = FK.UNIQUE_CONSTRAINT_SCHEMA
    and U.CONSTRAINT_NAME = FK.UNIQUE_CONSTRAINT_NAME
inner join INFORMATION_SCHEMA.KEY_COLUMN_USAGE R
    ON R.CONSTRAINT_CATALOG = FK.CONSTRAINT_CATALOG
    AND R.CONSTRAINT_SCHEMA = FK.CONSTRAINT_SCHEMA
    AND R.CONSTRAINT_NAME = FK.CONSTRAINT_NAME
WHERE U.COLUMN_NAME = 'a'
  AND U.TABLE_CATALOG = 'b'
  AND U.TABLE_SCHEMA = 'c'
  AND U.TABLE_NAME = 'd'

This uses the full catalog/schema/name triplet to identify a db table from all 3 information_schema views. You can drop one or two as required.

The query lists all tables that have a foreign key constraint against the column 'a' in table 'd'