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firebird-mirror/doc/sql.extensions/README.db_triggers.txt
2006-12-30 06:03:16 +00:00

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------------------
Database triggers
------------------
Author:
Adriano dos Santos Fernandes <adrianosf@uol.com.br>
Syntax:
<database-trigger> ::=
{CREATE | RECREATE | CREATE OR ALTER}
TRIGGER <name>
[ACTIVE | INACTIVE]
ON <event>
[POSITION <n>]
AS
BEGIN
...
END
<event> ::=
CONNECT
| DISCONNECT
| TRANSACTION START
| TRANSACTION COMMIT
| TRANSACTION ROLLBACK
Syntax rules:
1) Database triggers type can't be changed.
Events descriptions:
- CONNECT
Database connection established
A transaction is started
Triggers are fired - uncaught exceptions rollback the transaction,
disconnect the attachment and are returned to the client
The transaction is committed
- DISCONNECT
A transaction is started
Triggers are fired - uncaught exceptions rollback the transaction,
disconnect the attachment and are swallowed
The transaction is committed
The attachment is disconnected
- TRANSACTION START
Triggers are fired in the newly created transaction - uncaught
exceptions are returned to the client and the transaction is not created
- TRANSACTION COMMIT
Triggers are fired in the committing transaction - uncaught exceptions
rollback the triggers savepoint, the commit command is aborted and the
exception is returned to the client
- TRANSACTION ROLLBACK
Triggers are fired in the rolling-back transaction - changes done will
be rolled-back and exceptions are swallowed