Database tables and columns

Every persistent object in the Pega Platform database has an associated class (Rule-Obj-Class rule type). The Pega Platform uses a simple algorithm and information in Data-Admin-DB-Table instances to determine which table contains objects of which classes.

When in memory and on the clipboard, objects are known as instances and have an XML-like structure consisting of property names and text property values. These can be reviewed with the Clipboard tool.

When saved into the database, objects become rows of a table, with columns corresponding to scalar properties.

Required columns for tables

Every database table that you add to the Pega Platform database must contain these five columns:

  • pxObjClass — The Pega Platform class name, typically VARCHAR2(96).
  • pxCreateDateTime — The date, typically DATE. This column has a different name in a few tables.
  • pyLabel — A Short Description VARCHAR2(64)
  • pzInsKey — Primary key, always includes the pxObjClass value or a class group name, VARCHAR2 (255) NOT NULL. The pzInskey column is identified as the unique key to the table by using a constraint.
  • pzPVStream — The storage stream (BLOB).