Automagically rewrite postgresql foreign keys to properly structured names

rewirte-fk.sql

SELECT
  tc.constraint_name,
  tc.table_name,
  kcu.column_name,
  ccu.table_name  AS foreign_table_name,
  ccu.column_name AS foreign_column_name,
  format('ALTER TABLE "%s" RENAME CONSTRAINT %s TO fk_%s_%s;',
         tc.table_name, tc.constraint_name, tc.table_name, kcu.column_name)
FROM
  information_schema.table_constraints AS tc
  JOIN information_schema.key_column_usage AS kcu
    ON tc.constraint_name = kcu.constraint_name
  JOIN information_schema.constraint_column_usage AS ccu
    ON ccu.constraint_name = tc.constraint_name
WHERE constraint_type = 'FOREIGN KEY'
      AND tc.constraint_name not like 'fk\_%'