When external data is changed by application programs, it must be ensured that the data is consistent after changes have been made. This is particularly the case for the processing of data in the database. The time span during which a consistent data status is transferred to another consistent status is known as a LUW (Logical Unit of Work). If an error occurs during a LUW, it is possible to reset all changes made up to this point and regenerate the data in its original consistent status (rollback). When a new consistent status has been reached, this new status can be set and a new LUW can be opened (Commit).
In an AS ABAP there are two type of LUWs:
- Database LUWs that are realized by the database system
- SAP LUWs, that are realized using special ABAP proramming techniques
Accordingly, there are two lock types that are of significance:
- Database locks that are set by the system
- SAP locks that are set using special ABAP proramming techniques