BEGIN(7)

okay so bestie, this is the BEGIN(7) page from the PostgreSQL 16.15 docs, and it’s giving “tiny command, huge consequences.” 💅

🌸 NAME 🌸

BEGIN — start a transaction block. periodt. 👑

✨ 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 🦋

So BEGIN initiates a transaction block. Translation: all statements after a BEGIN command will be executed in a single transaction until an explicit COMMIT or ROLLBACK is given. no cap. 🫶

By default — meaning without BEGIN — PostgreSQL executes transactions in “autocommit” mode. That means 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. bestie, it’s one and done. 💀

Statements are executed more quickly in a transaction block, because transaction start/commit requires significant CPU and disk activity. slay for performance 🧚. 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. the vibe stays all-or-nothing. ✨

If the isolation level, read/write mode, or deferrable mode is specified, the new transaction has those characteristics, as if SET TRANSACTION was executed. keep that in mind. 💅

🎀 PARAMETERS 🎀

• WORK — optional key word. It has no effect. literally decorative. 🎀
• TRANSACTION — optional key word. It has no effect. same energy. ✨
• Refer to SET TRANSACTION (SET_TRANSACTION(7)) for information on the meaning of the other parameters to this statement. that’s the lore. 💖

🌈 NOTES 🌈

• START TRANSACTION has the same functionality as BEGIN. same slay, different name. 🫶
• Use COMMIT or ROLLBACK to terminate a transaction block. do not leave it hanging, bestie. 😭
• Issuing BEGIN when already inside a transaction block will provoke a warning message. The state of the transaction is not affected. so it’s loud, but not destructive. 💀
• To nest transactions within a transaction block, use savepoints — see SAVEPOINT(7). that’s the move. 🎀
• For reasons of backwards compatibility, the commas between successive transaction_modes can be omitted. cute. no notes. 😌

💖 EXAMPLES 💖

To begin a transaction block, you literally do:

BEGIN;

iconic. that’s it. 🦋

👑 COMPATIBILITY 👑

• BEGIN is a PostgreSQL language extension. It is equivalent to the SQL-standard command START TRANSACTION, whose reference page contains additional compatibility information. iykyk. 💅
• The DEFERRABLE transaction_mode is a PostgreSQL language extension. PostgreSQL stays extending ✨
• 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. this is a friendly warning, not a drill. 🚨

🌟 SEE ALSO 🌟

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

go read these next, bestie. the cross-refs are iconic. 💜

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💖 that’s the whole BEGIN(7) page from the PostgreSQL 16.15 docs, dated 2026 — go forth and transact responsibly, bestie. 🫶