Systems

system Transaction

The transaction system provides access control for data objects. A user can open a transaction and make data objects part of it, and other users are then prevented from chaning whatever is part of the transaction.

The general idea is to give the user a way to make multiple successive manipulations on the datastructure, possibly over long time with many calls, in an atomic way. For this he needs the gurantee, that only his calls change certain data, and noone else can make any unforseen changes he needs to react to. To achieve this the manipulated data can be made part of a transaction, which prevents anyone else to manipulate it.

To enable data objects for transaction use it needs to have one of the transaction behaviours added. In those behaviours the detailed handling of the Object withing the transaction can be specified.

Note

The dml transactions are different to SQL transactions as they are open for successive user calls, without a time limit. This does however also mean, that the user needs to take care of closing it correctly.

function IsOpen()

Checks if the user has currently a transaction open

Return

• open (bool) – True if a transaction is open

function Open()

Opens a transaction. If one is already open, it will be closed first.

function Close()

Closes the currently open transaction.

function Abort()

Aborts the current transaction and reverts all objects to the state they had when adding to the transaction