Choosing Physical Tuning Options › Placement of Entities in Areas › Segmentation of Databases › Segmenting by Groups of Entities

Segmenting by Groups of Entities

To facilitate processing of the same data by different application programs, you can create a database that is segmented by groups of entities, as shown below.

To create such a database, you assign entities to separate database areas and use only unlinked (as opposed to linked) relationships between entities in different areas. See "Linked and Unlinked Relationships" later in this chapter for further information on types of relationships.

Database segmented by groups of entities

Advantages

A database segmented by entity is advantageous because it:

• Eliminates the need to perform maintenance for linked relationships that cross areas and facilitates and shortens unload/reload operations.
• Allows certain application programs to remain active while parts of the database are being recovered or restructured.

Considerations

Although a database segmented by entity can facilitate certain processing functions, it can sometimes complicate processing of child entities. If an application requires the ability to group child entities by parent, the DBMS must use additional system resources to access the related entities that are stored in different areas.