TableSets
Before you set up the business units, decide on the TableSet structure and establish SetIDs.
When you plan the business unit structure, you need to understand TableSets, which are used in all PeopleSoft Financials applications.
The accounting structure and processing rules for each PeopleSoft application that you use are defined in a series of control tables. A TableSet is a group of rows shared across control tables and identified by the same SetID, on which you define the accounting structure for each business unit. For a business unit to process transactions, it must have an associated TableSet.
Several business units can share the control data in a TableSet; for example, suppliers are defined by SetID, and you can set up any number of business units to share the suppliers in a SetID.
Consider this relationship in simplified terms: the business unit contains all the actual data, and the TableSet contains the rules by which the data is processed. A SetID identifies each TableSet. You can have as many SetIDs as you like, but having numerous SetIDs makes TableSet sharing more complex. Create at least one SetID even if you do not take advantage of TableSet sharing. Some organizations need only one SetID.
WARNING:
In general, create SetIDs and business unit names that are five characters long. Performance degradation can occur (depending on the operating system) if SetIDs or business units have fewer than five characters.
See the product documentation for PeopleTools: Applications User's Guide