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1887.3.2
by Brian Aker
Extended documentation. |
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Using transactions
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1900.2.7
by Stewart Smith
fix docs warning: underline/overline too short for transactional.rst |
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==================
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1887.3.2
by Brian Aker
Extended documentation. |
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.. toctree:: |
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:maxdepth: 2
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start_transaction |
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commit |
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rollback |
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savepoints |
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1994.4.3
by Marisa Plumb
few updates and modifications to admin commands |
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The essence of a transaction is that it groups multiple steps into a single, all-or-nothing operation. Drizzle is a transactional database by default and by design, meaning that changes and queries to the database appear to be Atomic, Consistent, Isolated, and Durable (ACID). This means that Drizzle implements `serializable <http://en.wikipedia.org/wiki/Serializability>`_, ACID transactions, even if the transaction is interrupted. |
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1994.4.2
by Marisa Plumb
modified transaction docs |
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It collects operations that form tasks and stores them as a single operation, or if that operation is not possible it removes all changes attempted. Transactions are controlled via START TRANSACTION, ROLLBACK, and COMMIT. Savepoints are implemented to allow for a low leverl of granulairty. |
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1887.3.2
by Brian Aker
Extended documentation. |
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A COMMIT statement ends a transaction within Drizzle and makes all changes visible to other users. The order of events is typically to issue a START TRANSACTION statement, execute one or more SQL statements, and then issue a COMMIT statement. Alternatively, a ROLLBACK statement can be issued, which undoes all the work performed since START TRANSACTION was issued. A COMMIT statement will also release any existing savepoints that may be in use. |
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1994.4.2
by Marisa Plumb
modified transaction docs |
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Drizzle can operate in an autocommit mode, where each statement is committed, via: ::
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1887.3.2
by Brian Aker
Extended documentation. |
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1994.4.2
by Marisa Plumb
modified transaction docs |
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SET AUTOCOMMIT= 1
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1887.3.2
by Brian Aker
Extended documentation. |
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Currently DDL operations are performed as a single transaction, this limitation will be lifted in the future. |
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