Crude pg SQL to select Foreign Key relationships in Db

gistfile1.sql

SELECT 
    parent.table_name parent, 
    parent.constraint_name key_name, 
    tc.constraint_type key_type,
        (SELECT c.table_name 
            FROM information_schema.table_constraints c
            WHERE c.constraint_name = parent.constraint_name) child,
        (SELECT pid.column_name
            FROM information_schema.constraint_column_usage pid
            WHERE pid.constraint_name = parent.constraint_name) pid,
        (SELECT cid.column_name
            FROM information_schema.key_column_usage cid
            WHERE cid.constraint_name = parent.constraint_name) cid
FROM information_schema.table_constraints tc 
INNER JOIN information_schema.constraint_table_usage parent
ON parent.constraint_name = tc.constraint_name;