The Pega Platform database
The Pega Platform relational database holds the rules, data instances, work items, history, and other concrete objects from the internal classes of your Pega Platform system. External classes, by definition, correspond to tables in other databases and are not part of the Pega Platform database.
Tables and views in the Pega Platform database become visible when you
use Database Table instances (Data-Admin-DB-Table). For example, the
Data-Admin-Operator-ID class defines users and their organization. The
property pyUserName in that class can contain as its value a text string
for a user name. When your system is first installed, instances of the
Data-Admin-Operator-ID class are saved as rows in the
pr_operators database table, which are identified in the database table
instance named Data-Admin-Operator-ID. The column named
pyUserName contains the text string for the name.
Your applications can use report definition rules or the Obj-Browse method to generate SQL statements that search the database and generate reports. For security and performance reasons, the Pega Platform uses prepared statements to access the Pega Platform database. The SELECT, WHEN, and other parts of the SQL statements are parameters of the prepared statements.
For information about dividing large work tables and indexes into smaller and more manageable tablespaces, see the PDN article PegaRULES table partitioning.