Does SQL Server Automatically Roll Back Transactions on Error?

SQL Server Transaction Behavior and Error Handling

Understanding how SQL Server manages transactions, especially when errors occur, is vital for database integrity.

Scenario:

Consider a complex SQL command in SQL Server 2005, containing multiple INSERT statements within a transaction block. If one INSERT operation fails, what happens to the entire transaction?

Default Behavior:

By default, SQL Server does not automatically roll back a transaction upon encountering an error. The transaction remains open, requiring a manual ROLLBACK command to undo any changes.

Ensuring Automatic Rollback:

To guarantee automatic rollback on any error within a transaction, use the following setting before initiating the transaction:

<code class="language-sql">SET XACT_ABORT ON</code>

With XACT_ABORT enabled, a single failure within the transaction will trigger an automatic rollback, preserving data consistency and preventing partial updates.

Important Considerations:

• SET XACT_ABORT ON ensures either complete transaction success or a complete rollback.
• This setting applies globally to all transactions within the current database connection.
• Disabling this behavior (SET XACT_ABORT OFF) necessitates explicit ROLLBACK statements to handle failed transactions.

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