A user database is a collection of user data for one process model.
You associate each user database with a specific version of a specific schema. For example, in Figure 1 each user database uses a version of a schema stored in the schema repository. The schema defines the way the data is stored and changed in that database (that is, the user database is an instance of a version of a schema). Users change data in the user databases when they add or modify information about change requests, but these changes have no effect on the schema.
IBM® Rational® ClearQuest® stores change requests as records in user databases. As the change request moves through its lifecycle, the data stored in its record changes accordingly.
You can create and associate multiple user databases with a single schema. For example, if you have three projects that use the same process model for correcting defects, you could create one user database for each project and associate all three with the same schema. In Figure 1 two user databases use Version 3 of Schema A.