PeopleSoft database architecture 

It consists of three categories as follows:
SYSTEM CATALOG TABLE
PEOPLETOOLS TABLE
APPLICATION TABLE

SYSTEM CATALOG TABLE
This tables are handled by DBA’s since it has the DB related information along with it is used to check the performance of the peoplesoft DB.
Any change in the application tables updates the system catalog tables.
Example of system catalog tables are: SYSCOLUMS, SYSTABLES

PEOPLETOOLS TABLES
All delivered tables can be found in Peopletools Tables
The metadata is stored in Peopletools tables like fields, records, page, component, menu, AE.
Example of peopletools table are: PSRECDEFN, PSDBFIELD

APPLICATION TABLES
The tables we develop are stored in application tables.
PeopleSoft has prefered the naming convention of application tables to be starting with PS_
Example of application tables are: PS_JOB
PS_EMPL_TBL


Application tables are further categorized into three parts:

Control Table
Transaction Table
Runcontrol Table

* If any user want to add few more points related to peoplesoft database architecture your most welcome.