graphql-engine/server/src-rsr/trigger.sql.j2

CREATE OR REPLACE function hdb_views.{{QUALIFIED_TRIGGER_NAME}}() RETURNS trigger
   LANGUAGE plpgsql
   AS $$
   DECLARE
   id text;
   _old record;
   _new record;
   _data json;
   payload json;
   session_variables json;
   server_version_num int;
   BEGIN
     id := gen_random_uuid();
     server_version_num := current_setting('server_version_num');
     IF server_version_num >= 90600 THEN
       session_variables := current_setting('hasura.user', 't');
     ELSE
        BEGIN
          session_variables := current_setting('hasura.user');
        EXCEPTION WHEN OTHERS THEN
            session_variables := NULL;
        END;
     END IF;
     IF TG_OP = 'UPDATE' THEN
       _old := {{OLD_ROW}};
       _new := {{NEW_ROW}};
     ELSE
     /* initialize _old and _new with dummy values */
       _old := row((select 1));
       _new := row((select 1));
     END IF;
     _data := json_build_object(
       'old', {{OLD_PAYLOAD_EXPRESSION}},
       'new', {{NEW_PAYLOAD_EXPRESSION}}
     );
     payload := json_build_object(
                        'op', TG_OP,
                        'data', _data,
                        'session_variables', session_variables
                        )::text;
     IF (TG_OP <> 'UPDATE') OR (_old <> _new) THEN
       INSERT INTO
       hdb_catalog.event_log (id, schema_name, table_name, trigger_name, trigger_id, payload)
       VALUES
       (id, TG_TABLE_SCHEMA, TG_TABLE_NAME, '{{NAME}}', '{{ID}}', payload);
     END IF;
     RETURN NULL;
   END;
   $$;
   DROP TRIGGER IF EXISTS {{QUALIFIED_TRIGGER_NAME}} ON {{QUALIFIED_TABLE}};
   CREATE TRIGGER {{QUALIFIED_TRIGGER_NAME}} AFTER {{OPERATION}} ON {{QUALIFIED_TABLE}} FOR EACH ROW EXECUTE PROCEDURE hdb_views.{{QUALIFIED_TRIGGER_NAME}}();