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70 lines
1.8 KiB
Plaintext
70 lines
1.8 KiB
Plaintext
------------------
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Database triggers
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------------------
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Author:
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Adriano dos Santos Fernandes <adrianosf@uol.com.br>
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Syntax:
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<database-trigger> ::=
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{CREATE | RECREATE | CREATE OR ALTER}
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TRIGGER <name>
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[ACTIVE | INACTIVE]
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ON <event>
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[POSITION <n>]
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AS
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BEGIN
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...
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END
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<event> ::=
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CONNECT
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| DISCONNECT
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| TRANSACTION START
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| TRANSACTION COMMIT
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| TRANSACTION ROLLBACK
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Syntax rules:
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1) Database triggers type can't be changed.
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Utilities support:
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New parameters were added to GBAK, ISQL and NBACKUP to not run database triggers.
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These parameters could only be used by database owner and SYSDBA:
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GBAK -nodbtriggers
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ISQL -nodbtriggers
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NBACKUP -T
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Permissions:
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Only database owner and SYSDBA can do database triggers DDL.
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Events descriptions:
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- CONNECT
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Database connection established
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A transaction is started
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Triggers are fired - uncaught exceptions rollback the transaction,
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disconnect the attachment and are returned to the client
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The transaction is committed
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- DISCONNECT
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A transaction is started
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Triggers are fired - uncaught exceptions rollback the transaction,
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disconnect the attachment and are swallowed
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The transaction is committed
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The attachment is disconnected
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- TRANSACTION START
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Triggers are fired in the newly user created transaction - uncaught
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exceptions are returned to the client and the transaction is rolled-back.
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- TRANSACTION COMMIT
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Triggers are fired in the committing transaction - uncaught exceptions
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rollback the triggers savepoint, the commit command is aborted and the
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exception is returned to the client.
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Note: for two-phase transactions the triggers are fired in "prepare"
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and not in commit.
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- TRANSACTION ROLLBACK
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Triggers are fired in the rolling-back transaction - changes done will
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be rolled-back togheter with the transaction and exceptions are swallowed
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