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The DDL_TRIGGER Namespace

The DDL_TRIGGER namespace is valid only when a DDL trigger is running.Its use is also valid in stored procedures and functions when called by DDL triggers.

The DDL_TRIGGER context works like a stack.Before a DDL trigger is fired, the values relative to the executed command are pushed onto this stack.After the trigger finishes, the values are popped.So in the case of cascade DDL statements, when a user DDL command fires a DDL trigger and this trigger executes another DDL command with EXECUTE STATEMENT, the values of the DDL_TRIGGER namespace are the ones relative to the command that fired the last DDL trigger on the call stack.

Context variables in the DDL_TRIGGER namespace
EVENT_TYPE

event type (CREATE, ALTER, DROP)

OBJECT_TYPE

object type (TABLE, VIEW, etc)

DDL_EVENT

event name (<ddl event item>), where <ddl event item> is EVENT_TYPE || ' ' || OBJECT_TYPE

OBJECT_NAME

metadata object name

OLD_OBJECT_NAME

for tracking the renaming of a domain (see note)

NEW_OBJECT_NAME

for tracking the renaming of a domain (see note)

SQL_TEXT

sql statement text

Note

ALTER DOMAIN old-name TO new-name sets OLD_OBJECT_NAME and NEW_OBJECT_NAME in both BEFORE and AFTER triggers.For this command, OBJECT_NAME will have the old object name in BEFORE triggers, and the new object name in AFTER triggers.

Examples

select rdb$get_context('SYSTEM', 'DB_NAME') from rdb$database

New.UserAddr = rdb$get_context('SYSTEM', 'CLIENT_ADDRESS');

insert into MyTable (TestField)
  values (rdb$get_context('USER_SESSION', 'MyVar'))
See also

[fblangref50-scalarfuncs-set-context]