Create an edge list of relations being related by foreign key [postgres]

edgelist.sql

-- Pre: The names of the relations to consider are in a relation named nodes in
--      the public schema (it could be parametrized)

SELECT
    tc.table_name watcher
  , ctu.table_name target
FROM
             information_schema.table_constraints tc
  INNER JOIN information_schema.constraint_table_usage ctu ON tc.constraint_name = ctu.constraint_name
  INNER JOIN nodes pt ON tc.table_name = pt."name"
WHERE
      tc.constraint_type = 'FOREIGN KEY'
  AND tc.table_schema = 'public'
  AND ctu.table_schema = 'public'