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 ABAP system, there are two type of LUWs:
Accordingly, there are two lock types that are of significance:
Finally, the authorizations of a user are important for data consistency for accessing data whose check has an ABAP statement.