The

When a DDL trigger is running, the DDL_TRIGGER namespace is available for use with RDB$GET_CONTEXT.This namespace contains information on the currently firing trigger.

See also The DDL_TRIGGER Namespace in RDB$GET_CONTEXT in [fblangref50-functions].

For information on creating triggers, see CREATE TRIGGER, CREATE OR ALTER TRIGGER, and RECREATE TRIGGER in [fblangref50-ddl].