Working with the PegaRULES database — Tables for work items
Working with the PegaRULES database — Tables for work items |
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Work items are the primary unit of processing in applications that use flows. A large fraction of database processing involves creating and updating work items. Updates to related objects, such as assignments and attachments, usually also require updates to the work item.
As initially configured during installation, PRPC saves work items — instances of concrete classes derived from the Work- base class — in the pc_work table, except as described here
A work pool, defined by a class group instance, causes all work items for an application to be stored in a single shared database table. This sharing is helpful in searching and reporting on work items. With appropriate safeguards, this also allows a work item to be reclassified from one work 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 work item was initially created with the wrong work 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 through a wizard or tool. The structure of the new table is similar to the initial structure of the pc_work table. See More about Database Table data instances.
The pc_work table demonstrates work pools, and serves as a default table for work items. 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, a dedicated table for work items is desirable for each application, as described below.
Creating a dedicated table for a work pool
If your PRPC system hosts two or more unrelated applications each with one or more work pools, it is usually desirable to store work items for each application in a dedicated table, using the structure of the pc_work table. Keeping each application's work items in a dedicated database table is recommended, because:
SELECT operations) is improvedIf you create the applications through Application Express each work pool has a dedicated table named pc_ZZZZZ_Work, which initially is a copy of the pc_work table, and the steps below are not necessary.
If your pc_work table contains work items from two or more unrelated applications, use these steps to segregate work items into a dedicated table:
pc_work table. Be certain to update the CONSTRAINT element in the new table to reference itself, not the old pc_work table.pc_history_work table.pcv4_assignment_summary and pcv4_assignmentwb_summary and adjust them to reference the new tables.Many wizards and developer tools available in the Designer Studio — for example, the Product Migration wizard — are implemented as screen flows and create work items in your system. The work types of such work items start with PegaAccel-Task-.
The PegaAccel-Task- class is mapped to the pc_work_accel database table. This ensures that work items produced by developer tools are saved in a dedicated table separate from work items from business applications. Such separation improves reporting performance.
The Pega-Events class and subclasses support the Designer Studio's What's Happening display, RSS feed, and the Recent Actions landing page tab. These classes are derived from the Work- base class. To simplify reporting on work items of your applications, instances of these classes are saved in a dedicated database table, pc_events. See Designer Studio — Working with the What's Happening display
The pc_scheduledtask table
The pc_schedule_task table contains work items for scheduled reports, instances of the Pega_ScheduledTask class. See Report Definitions — Scheduling reports.
Standard reports on work items depend on the exposed columns in the schema of two tables:
pc_work, for work itemspc_history_work, for history instances for work itemsAs initially installed, PRPC stores work items in the pc_work table, and work item history instances in the pc_history_work table. This relationship is defined by the two database table instances Work- and History-Work-.
Reporting on work and work history (such as provided by the links on the Monitor Process workspace) depends on the columns of these two tables.
When a developer creates new work types (and corresponding work history classes) using the Application Accelerator, the system maps the new work classes appropriately into these two tables.
However, when a developer creates a new concrete class using the Class form, the default mapping is to the pr_other table (and the pr_history table, for history). These mappings are not appropriate for work items and may cause SQL errors or JavaScript failures. You can remedy this by adding the two appropriate database table instances.
Two standard database views are linked to the Data-Assignment-Summary and Data-Assignment-WBSummary classes. These support custom worklist and assignment reporting; update these view definitions if you use these views and you change or copy the pc_work table.
This PDN article provides more information on this strategy: Troubleshooting: instances were not saved in the expected table of the PegaRULES database
The pc_work_dsm_batch table supports work items created through Decision Strategy Manager, instances of the Pega-DM-Batch-Work class.. This table is empty unless you use DSM facilities.
The pc_Work_ProcessEmail table
Used internally to support work processing derived from incoming emails.. The Work-ProcessEmail class is linked to this table. See Understanding email-based work processing.
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.
Note: With Pega 7.1.7 local data storage replaces data tables.
