Case tables
Cases are the primary units of processing in applications that use flows. A large fraction of database processing involves creating and updating cases. Updates to related objects, such as assignments and attachments, usually also require updates to the case.
 As configured during installation, Pega Platform saves cases—instances
        of concrete classes derived from the Work- base class—in the
          pc_work  table, except as described in this topic. 
Class groups and work pools
A work pool, defined by a class group instance, causes all cases for an application to be stored in a single shared database table. This sharing is helpful for searching and reporting on cases. With appropriate safeguards, this also allows a case to be reclassified from one case type to another (when both are in the same work pool). Such reclassification can be a typical, normal aspect of the application workflow, or can indicate that the case was initially created with the wrong case type.
 In development systems (only), the system can automatically create a database table (and
        associated Data-Admin-DB-Table data instance) each time you create a work
        pool, directly from the class form or indirectly using a wizard or tool. The structure of
        the new table is similar to the initial structure of the pc_work table.
      
pc_work table
 The pc_work table demonstrates work pools, and serves as a default table
        for cases. As initially configured during installation, the system saves work items from the
        PegaSample application and from certain developer tools in the pc_work
        table. 
As a best practice, use a dedicated table for cases for each application.
 If your system hosts two or more unrelated applications each with one or more work pools,
        store work items for each application in a dedicated table, using the structure of the
          pc_work table. A dedicated database table is recommended because: 
-  It improves report performance (based on SQL SELECToperations)
- It makes insert operations faster when new cases are created
In addition, different applications might need different properties exposed as database columns
 If you create the applications using the New Application wizard, each work pool has a
        dedicated table named pc_ZZZZZ_Work, which is a copy of the pc_work table,
        and you do not have to segregate cases into a dedicated table. 
 If your pc_work table contains cases from two or more unrelated
        applications, segregate cases into a dedicated table. 
PEGA0041 alert
 If an appropriate data table mapping is undefined for a work type (or an entire work
        pool), the system saves the work item in the pr_other table. This is
        undesirable except in rare cases where only a few rarely searched work items are expected.
        To notify developers or system administrators that work items are saved in that table, the
        system creates a PEGA0041 alert.