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SQL refers to Structured Query Language, a kind of language used to access, update and manipulate database. In SQL, ROLLBACK is a command that causes all data changes since the last START TRANSACTION or BEGIN to be discarded by the relational database management systems (RDBMS), so that the state of the data is "rolled back" to the way it was before those changes were made.
A savepoint is a way of implementing subtransactions (also known as nested transactions) within a relational database management system by indicating a point within a transaction that can be "rolled back to" without affecting any work done in the transaction before the savepoint was created. Multiple savepoints can exist within a single ...
1. In the context of a database this is often easily achieved using transactions and the commit/rollback mechanism. [1] Compensating transaction logic could be implemented as additional on top of database supporting commit/rollback. In that case, we can decrease business transaction granularity.
In terms of transactions, the opposite of commit is to discard the tentative changes of a transaction, a rollback. The transaction, commit and rollback concepts are key to the ACID property of databases. [1] A COMMIT statement in SQL ends a transaction within a relational database management system (RDBMS
A database transaction symbolizes a unit of work, performed within a database management system (or similar system) against a database, that is treated in a coherent and reliable way independent of other transactions. A transaction generally represents any change in a database. Transactions in a database environment have two main purposes:
COMMIT and ROLLBACK terminate the current transaction and release data locks. In the absence of a START TRANSACTION or similar statement, the semantics of SQL are implementation-dependent. The following example shows a classic transfer of funds transaction, where money is removed from one account and added to another.
It is also possible to keep a separate journal of all modifications to a database management system. (sometimes called after images).This is not required for rollback of failed transactions but it is useful for updating the database management system in the event of a database failure, so some transaction-processing systems provide it.
Nonetheless, in systems such as Microsoft SQL Server, as well as connection technologies such as ODBC and Microsoft OLE DB, autocommit mode is the default for all statements that change data, in order to ensure that individual statements will conform to the ACID (atomicity-consistency-isolation-durability) properties of transactions.