Triggers — ASL

Triggers

A trigger inside a type body attaches to that table. Its body is either an inline AQL statement (do ( … ), the default) or a reference to a declared function (execute <fn>()).

type Application extends Base {
  required name: str;

  # Inline AQL — __new__.field is validated against Application
  trigger audit after insert, update, delete do (
    insert AuditLog {
      table_name := 'application',
      action := event,
      new_data := to_jsonb(__new__)
    }
  );

  # Or reference a declared function
  trigger touch before update execute slugify_name();
}

Timing is before | after; events are a comma-separated list of insert / update / delete. Optional clauses: for each row (default) or for each statement, and when ( $$ <sql condition> $$ ). An inline do body compiles to a generated function plus the trigger; the SQL is ordered extensions → tables → functions → triggers so a body that writes to another table sees it exist.

On a DELETE, NEW is null — don’t reference __new__ in a delete-only path.

See Functions for the magic identifiers (__new__, event, …) available inside an inline do body.