text: CREATE TABLE "public"."teaches"("id" serial NOT NULL, "created_at" timestamptz NOT NULL DEFAULT now(), "updated_at" timestamptz NOT NULL DEFAULT now(), "instructor_id" integer NOT NULL, "subject_id" integer NOT NULL, PRIMARY KEY ("id") , FOREIGN KEY ("instructor_id") REFERENCES "public"."instructors"("id") ON UPDATE cascade ON DELETE cascade, FOREIGN KEY ("subject_id") REFERENCES "public"."subjects"("id") ON UPDATE cascade ON DELETE cascade, UNIQUE ("instructor_id", "subject_id"));
  CREATE OR REPLACE FUNCTION "public"."set_current_timestamp_updated_at"()
  RETURNS TRIGGER AS $$
  DECLARE
    _new record;
  BEGIN
    _new := NEW;
    _new."updated_at" = NOW();
    RETURN _new;
  END;
  $$ LANGUAGE plpgsql;
  CREATE TRIGGER "set_public_teaches_updated_at"
  BEFORE UPDATE ON "public"."teaches"
  FOR EACH ROW
  EXECUTE PROCEDURE "public"."set_current_timestamp_updated_at"();
  COMMENT ON TRIGGER "set_public_teaches_updated_at" ON "public"."teaches" 
  IS 'trigger to set value of column "updated_at" to current timestamp on row update';
  