BEGIN(7)

BEGIN(7) — start a transaction block 💅

okay so welcome to the BEGIN(7) page from the PostgreSQL 13.23 Documentation, bestie — we're talking transaction blocks and you're gonna get it 💖

🌸 NAME 🌸

BEGIN — start a transaction block

✨ SYNOPSIS ✨

BEGIN [ WORK | 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 💖

okay so BEGIN initiates a transaction block. That means every statement after a BEGIN command gets executed in a single transaction until an explicit COMMIT(7) or ROLLBACK(7) is given. No cap.

By default — like, without BEGIN — PostgreSQL executes transactions in “autocommit” mode, that is, each statement is executed in its own transaction and a commit is implicitly performed at the end of the statement (if execution was successful, otherwise a rollback is done).

Statements are executed more quickly in a transaction block, because transaction start/commit requires significant CPU and disk activity. Execution of multiple statements inside a transaction is also useful to ensure consistency when making several related changes: other sessions will be unable to see the intermediate states wherein not all the related updates have been done.

If the isolation level, read/write mode, or deferrable mode is specified, the new transaction has those characteristics, as if SET TRANSACTION (SET_TRANSACTION(7)) was executed.

🎀 PARAMETERS 🎀

• WORK — optional key word. It has no effect. Literally zero effect, bestie 💅
• TRANSACTION — optional key word. It also has no effect. Same energy ✨

Refer to SET TRANSACTION (SET_TRANSACTION(7)) for information on the meaning of the other parameters to this statement.

🦋 NOTES 🦋

START TRANSACTION (START_TRANSACTION(7)) has the same functionality as BEGIN.

Use COMMIT(7) or ROLLBACK(7) to terminate a transaction block.

Issuing BEGIN when already inside a transaction block will provoke a warning message. The state of the transaction is not affected. To nest transactions within a transaction block, use savepoints (see SAVEPOINT(7)).

For reasons of backwards compatibility, the commas between successive transaction_modes can be omitted.

🌈 EXAMPLES 🌈

To begin a transaction block:

BEGIN;

⭐ COMPATIBILITY ⭐

BEGIN is a PostgreSQL language extension. It is equivalent to the SQL-standard command START TRANSACTION (START_TRANSACTION(7)), whose reference page contains additional compatibility information.

The DEFERRABLE transaction_mode is a PostgreSQL language extension.

Incidentally, the BEGIN key word is used for a different purpose in embedded SQL. You are advised to be careful about the transaction semantics when porting database applications.

👑 SEE ALSO 👑

• COMMIT(7)
• ROLLBACK(7)
• START TRANSACTION (START_TRANSACTION(7))
• SAVEPOINT(7)

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💖 that’s the whole BEGIN(7) vibe, sourced from PostgreSQL 13.23, dated 2025 — go forth and commit (or rollback), bestie! 💅✨