| title | Transactions (Transact-SQL) | Microsoft Docs | ||||
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| ms.custom | |||||
| ms.date | 09/25/2017 | ||||
| ms.prod | sql | ||||
| ms.prod_service | database-engine, sql-database, sql-data-warehouse, pdw | ||||
| ms.service | |||||
| ms.component | t-sql|language-elements | ||||
| ms.reviewer | |||||
| ms.suite | sql | ||||
| ms.technology |
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| ms.tgt_pltfrm | |||||
| ms.topic | language-reference | ||||
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| ms.assetid | 1485c375-921a-42af-a871-bb333cc08d3e | ||||
| caps.latest.revision | 24 | ||||
| author | douglaslMS | ||||
| ms.author | douglasl | ||||
| manager | craigg | ||||
| ms.workload | Active |
[!INCLUDEtsql-appliesto-ss2008-all-md]
A transaction is a single unit of work. If a transaction is successful, all of the data modifications made during the transaction are committed and become a permanent part of the database. If a transaction encounters errors and must be canceled or rolled back, then all of the data modifications are erased.
[!INCLUDEssNoVersion] operates in the following transaction modes:
Autocommit transactions
Each individual statement is a transaction.
Explicit transactions
Each transaction is explicitly started with the BEGIN TRANSACTION statement and explicitly ended with a COMMIT or ROLLBACK statement.
Implicit transactions
A new transaction is implicitly started when the prior transaction completes, but each transaction is explicitly completed with a COMMIT or ROLLBACK statement.
Batch-scoped transactions
Applicable only to multiple active result sets (MARS), a [!INCLUDEtsql] explicit or implicit transaction that starts under a MARS session becomes a batch-scoped transaction. A batch-scoped transaction that is not committed or rolled back when a batch completes is automatically rolled back by [!INCLUDEssNoVersion].
Note
For special considerations related to Data Warehouse products, see Transactions (SQL Data Warehouse).
[!INCLUDEssNoVersion] provides the following transaction statements:
| BEGIN DISTRIBUTED TRANSACTION | ROLLBACK TRANSACTION |
| BEGIN TRANSACTION | ROLLBACK WORK |
| COMMIT TRANSACTION | SAVE TRANSACTION |
| COMMIT WORK |
SET IMPLICIT_TRANSACTIONS (Transact-SQL)
@@TRANCOUNT (Transact-SQL)