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Synchronization Stamps

Table and Area Level Stamps

For SQL segments, you can specify whether synchronization stamps are to be maintained at the table or area level.

The synchronization stamp is used to make sure that the logical database definition in the access module corresponds to the current logical database definition in the dictionary.

Note: The synchronization stamp specification in the area definition included in the DMCL must be the same as that in the application dictionary in which the tables are defined.

At runtime, if the runtime system finds that the stamps in the access module and the database are not in sync, the access module is automatically recreated (if that option has been selected) or an error message is issued.

If you specify that the stamp is to be maintained at the table level, the stamp will be updated for an individual table when the definition of the table or any associated CALC, index, or constraint definition is modified.

If you specify that the stamp is to be maintained at the area level, the stamp will be updated when the definition of any table (or any associated CALC, index, or constraint definition) in the area is modified.

Which Type of Synchronization Stamp to Use

If changes to the logical structure of your database are rare (generally the case for databases in production), use area level synchronization stamps because they incur less overhead at runtime to validate. If your logical database definition changes frequently, as in a test or information center environment, choose table level synchronization stamps because a change in the definition of one table has no impact on the stamp value of other tables.