DF_TRAN_COUNT

See Also: Get_Attribute, Set_Attribute, Begin_Transaction, End_Transaction, Abort_Transaction, Lock, Reread, Unlock

Indicates the number of nested transactions.

Type

Numeric, temporary

Access

Read only

Values

Positive integer

Remarks

In DataFlex, it is allowed to nest transactions. When this occurs, the outer transaction logic will execute, and DF_TRAN_COUNT is incremented. The nested transactions will merely increment the DF_TRAN_COUNT attribute when started and decrement it again when they finish. When the outer transaction finishes, the transaction logic will execute, and DF_TRAN_COUNT will be decremented. An execution of Abort_Transaction will set DF_TRAN_COUNT to 0 (zero), as will the abortion of a transaction due to an error condition.

DataFlex supports two types of transactions:

• Explicit Transaction: Started by the Begin_Transaction command and ended by the End_Transaction command.
• Implicit Transaction: Started via the Lock or Reread command and ended via the Unlock command.

Example

The following sample procedure demonstrates the transaction count when nesting transactions:

Procedure DemoTranCount
    Integer iTranCount

    Get_Attribute DF_TRAN_COUNT To iTranCount
    Showln "Current transaction count: " iTranCount

    Begin_Transaction
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount

        Begin_Transaction
            Get_Attribute DF_TRAN_COUNT To iTranCount
            Showln "Current transaction count: " iTranCount

            Begin_Transaction
                Get_Attribute DF_TRAN_COUNT To iTranCount
                Showln "Current transaction count: " iTranCount

                Begin_Transaction
                    Get_Attribute DF_TRAN_COUNT To iTranCount
                    Showln "Current transaction count: " iTranCount
                End_Transaction

                Get_Attribute DF_TRAN_COUNT To iTranCount
                Showln "Current transaction count: " iTranCount
            End_Transaction

            Get_Attribute DF_TRAN_COUNT To iTranCount
            Showln "Current transaction count: " iTranCount
        End_Transaction

        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount
    End_Transaction

    Get_Attribute DF_TRAN_COUNT To iTranCount
    Showln "Current transaction count: " iTranCount

    Begin_Transaction
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount

        Lock
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount

        Reread
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount

        Lock
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount

        Unlock
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount

        Unlock
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount

        Unlock
        Get_Attribute DF_TRAN_COUNT To iTranCount
        Showln "Current transaction count: " iTranCount
    End_Transaction

    Get_Attribute DF_TRAN_COUNT To iTranCount
    Showln "Current transaction count: " iTranCount
End_Procedure // DemoTranCount

The output of this procedure will show a transaction count incrementing up to 4, then decrementing to 0, incrementing again up to 4, and decrementing again to 0.