Create or replace trigger postgres

Question

I want to \"create or replace\" a trigger for a postgres table. However, there is not such sql expression.

I see that I can do a \"DROP TRIGGER IF EXISTS\"

Answer 1

You can combine CREATE OR REPLACE FUNCTION trigger_function with the following script in your SQL:

DO $$
BEGIN
  IF NOT EXISTS(SELECT *
    FROM information_schema.triggers
    WHERE event_object_table = 'table_name'
    AND trigger_name = 'trigger_name'
  )
  THEN
    CREATE TRIGGER trigger_name AFTER INSERT ON table_name FOR EACH ROW EXECUTE PROCEDURE trigger_function();
  END IF;
END;
$$