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Wiki / SQL Commands

START TRANSACTION

start a transaction block

English manual coverage begins with PostgreSQL 6.4. Source history and runtime observations have their own recorded version boundaries.

Reading PG 18·Select a recorded version

7.37.48.08.18.28.38.49.09.19.29.39.49.59.61011121314151617181920
anchor
SQL-START-TRANSACTION
file
sql-start-transaction.html
lang
en
name
START TRANSACTION
purpose
start a transaction block
purpose zh
开始一个事务块
sections same as
Unknown
slug
18
synopsis text
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

Syntax

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
Syntax diagrams

Read left to right. Branches are choices, bypasses are optional, loops repeat. Select an underlined parameter to open its rule.

START TRANSACTION transaction_mode ,
transaction_mode
ISOLATION LEVEL SERIALIZABLE REPEATABLE READ READ COMMITTED READ UNCOMMITTED READ WRITE READ ONLY NOT DEFERRABLE

Definition PG 18

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.

See Also

BEGIN, COMMIT, ROLLBACK, SAVEPOINT, SET TRANSACTION

Compare versions

Complete source facts

synopsis html

START TRANSACTION [ <em class="replaceable"><code>transaction_mode</code></em> [, ...] ]

<span class="phrase">where <em class="replaceable"><code>transaction_mode</code></em> is one of:</span>

    ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED }
    READ WRITE | READ ONLY
    [ NOT ] DEFERRABLE

Source references

Full definition and evidence JSON

Definition sources

center · PostgreSQL 18 · wiki-repair-20261023:364717d4808e75aa22bc726d603c2b42f94cd538e9b8ae8e83f401fe56ed0fda

Text language: en · wiki-repair-20261023:364717d4808e75aa22bc726d603c2b42f94cd538e9b8ae8e83f401fe56ed0fda