# START TRANSACTION
START TRANSACTION — start a transaction block
# Synopsis
START TRANSACTION [ transaction_mode [, ...] ]
where transaction_mode is 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.
# 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. PostgreSQL'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 PostgreSQL language extension.
The SQL standard requires commas between successive transaction_modes
, but for historical reasons PostgreSQL allows the commas to be omitted.
See also the compatibility section of SET TRANSACTION.