Firebird 2.1 Language Reference Update

Example:
DDL statements
create trigger biu_books
active before insert or update position 3
on books
as
begin
if (new.id is null)
then new.id = next value for gen_bookids;
end
Database triggers
Added in: 2.1
Description: Since Firebird 2.1, triggers can be defined to fire upon the database events CONNECT, DISCON-
NECT, TRANSACTION START, TRANSACTION COMMIT and TRANSACTION ROLLBACK. Only the database
owner and SYSDBA can create, alter and drop these triggers.
Syntax:
Example:
CREATE TRIGGER name
[ACTIVE | INACTIVE]
ON db_event
[POSITION number]
AS
[]
BEGIN
[]
END
db_event ::= CONNECT | DISCONNECT | TRANSACTION START
| TRANSACTION COMMIT | TRANSACTION ROLLBACK
number ::= 0..32767 (default is 0)
::= See PSQL::DECLARE for the exact syntax
create trigger tr_connect
on connect
as
begin
insert into dblog (wie, wanneer, wat)
values (current_user, current_timestamp, 'verbind');
end
Execution of database triggers and handling of exceptions:
• CONNECT and DISCONNECT triggers are executed in a transaction created specifically for this purpose. If
all goes well, the transaction is committed. Uncaught exceptions roll back the transaction, and:
- In the case of a CONNECT trigger, the connection is then broken and the exception returned to the client.
- With a DISCONNECT trigger, exceptions are not reported and the connection is broken as foreseen.
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