Find referenced field(s) of foreign key constraint

Question

I have a table Users with a field called org_id which is a foreign key to a table organisation, with primary key field organisation_id

Answer 1

This query adds the referenced column(s) for the foreign key constraint:

SELECT c.confrelid::regclass::text AS referenced_table
      ,string_agg(f.attname, ', ') AS referenced_columns
      ,c.conname AS fk_name
      ,pg_get_constraintdef(c.oid) AS fk_definition
FROM   pg_attribute  a 
JOIN   pg_constraint c ON (c.conrelid, c.conkey[1]) = (a.attrelid, a.attnum)
JOIN   pg_attribute  f ON f.attrelid = c.confrelid
                      AND f.attnum = ANY (confkey)
WHERE  a.attrelid = '"Schema"."Users"'::regclass   -- table name
AND    a.attname  = 'org_id'                       -- column name  
AND    c.contype  = 'f'
GROUP  BY c.confrelid, c.conname, c.oid;

A fk constraint can reference multiple columns. That's the reason for the aggregate function string_agg() in the query.