SAS/ACCESS Interface to SYSTEM 2000 Data Management Software: Reference

Enabling the Rollback Log

A single SAS observation can be composed of one or more SYSTEM 2000 database records. Therefore, a single SYSTEM 2000 update command to update a given observation might involve several internal SYSTEM 2000 update commands. If one of these update commands fails after several others have already succeeded, the status of the entire update is incomplete.

In order to guarantee the data integrity, you must enable the rollback feature. You can do this easily with the QUEST procedure, by issuing the ENABLE ROLLBACK statement from the CONTROL language. When you enable rollback, you must be sure that the Rollback Log (database File 8) and the Update Log (database File 7) are allocated. With rollback enabled, the SYSTEM 2000 software can roll back the database to its status just prior to the sequence of commands that triggered the error.

If rollback is not enabled, partial updates can occur in the event of error return codes. Errors could arise from security violations or from bad data, for example, data that do not match the SAS informat or that have too many significant decimal places for a specific item's numerical precision. Also, if LHOLD=YES is specified in the SYSTEM 2000 execution parameters and rollback is not enabled, the interface view engine could receive return code 111, which causes an update to be rejected.

Chapter Contents
Previous
Next
Top of Page