START TRANSACTION
START TRANSACTION — start a transaction block
Synopsis
START [ AUTONOMOUS ] TRANSACTION [transaction_mode[, ...] ] wheretransaction_modeis one of: ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED } READ WRITE | READ ONLY [ NOT ] DEFERRABLE
Description
This command begins a new transaction block. If the isolation level, read/write mode, or deferrable mode is specified, the new transaction has those characteristics, as if SET TRANSACTION was executed. This is the same as the BEGIN command.
If you specify an optional AUTONOMOUS keyword, an autonomous transaction is started. Autonomous transactions can be started only within another transaction. For details, see Chapter 16.
Parameters
Refer to SET TRANSACTION for information on the meaning of the parameters to this statement.
Compatibility
In the standard, it is not necessary to issue START TRANSACTION to start a transaction block: any SQL command implicitly begins a block. Postgres Pro's behavior can be seen as implicitly issuing a COMMIT after each command that does not follow START TRANSACTION (or BEGIN), and it is therefore often called “autocommit”. Other relational database systems might offer an autocommit feature as a convenience.
The DEFERRABLE transaction_mode is a Postgres Pro language extension.
The SQL standard requires commas between successive transaction_modes, but for historical reasons Postgres Pro allows the commas to be omitted.
See also the compatibility section of SET TRANSACTION.