PRACTICAL GUIDEUnder review

Transactions and rollback in Protheus

Defines the write unit and cancellation flow.

Transactions and rollback in ProtheusAdvPL

01 · OVERVIEW

Overview

Official guidance uses BEGIN/END TRANSACTION and prohibits BeginTran/EndTran in the ERP. DisarmTransaction unwinds from the first open level and enters TTSBREAK; follow it with Break or thread termination under the documented contract. Do not open another transaction before unwinding all pending levels. This no-write lab refuses an existing transaction or TTSBREAK; it demonstrates flow rather than proving data rollback. FWInTTSBreak requires a compatible LIB, documented for versions after 08022017. (Sources: refs. 1–1.)

03 · PRACTICAL EXAMPLE

Commented example

#Include "Protheus.ch"

User Function Ed693()
    // Isolated lab: do not interfere with a caller-owned transaction.
    If InTransact() .Or. FWInTTSBreak()
        Return Nil
    EndIf
    Begin Transaction
        // No writes: demonstrate only the documented exit flow.
        DisarmTransaction()
        Break
    End Transaction
    ConOut("Flow completed")
Return Nil

Expected result

When outside a transaction and TTSBREAK, traverses an empty cancelled transaction. There is no data to roll back. Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

BEST PRACTICES

Open transactions near writes. Avoid input/network waits while holding locks. Database rollback cannot undo email or external APIs; plan those effects separately.
Under review: editorial example neither compiled nor run in Protheus. Check includes, release, RDD and context before testing.

Transactions and rollback in Protheus

Overview

Commented example

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