Analyzing the modifications to the database schema and adapting stored data to the modified schema is the task of the BALTER utility routine. BALTER controls these processes in two phases:
in the analysis phase BALTER analyzes the modifications to the database schema
In the optional REPORT phase BALTER outputs the analysis report
in the restructuring phase BALTER adapts the stored data and the definition of the database to the modified schema
In order to run BALTER successfully, you must first use the BGSIA utility routine to create the new SIA and enter it into the DBDIR (see section "Generating a new SIA and entering it in the DBDIR with BGSIA"). Otherwise, the BALTER run will abort with the message “BGSIA HAS NOT BEEN EXECUTED”.
When required, BALTER automatically extends the realms of the database being processed. For details, please refer to the "Database Operation" manual, Automatic realm extension by means of utility routines.
At startup BALTER takes into account any assigned UDS/SQL pubset declaration (see the "Database Operation" manual, Pubset declaration job variable). Faulty assignment leads to the program aborting.