When to Use Primary Keys

DBEngine supports ORDERED and COMPACT data sets regardless if they have unique key sets or not. Accessories, on the other hand, support ORDERED and COMPACT data sets as follows:

• Span Accessory does not require that ORDERED and COMPACT data sets have unique key sets.
• Snapshot requires that ORDERED and COMPACT data sets have unique key sets. If the ORDERED and COMPACT data sets do not have a unique key set defined in DMSII, you can define one via the GenFormat program.
• DATABridge Clients require that ORDERED and COMPACT data sets have unique key sets. Use the GenFormat program to set primary keys that define unique keys for data sets, or set the key items manually in the client control tables.

  Note: If you cannot generate using primary keys and you have DMSII XE, you can use it to uniquely identify each record.