34.1. The Problem: Persistent Objects
Assume that in the NextGen application, ProductSpecification data resides in a relational database. It must be brought into local memory during application use. Persistent objects are those that require persistent storage, such as ProductSpecification instances.
Storage Mechanisms and Persistent Objects
Object databases— If an object database is used to store and retrieve objects, no additional custom or third-party persistence services are required. This is one of several attractions for its use.
Relational databases— Because of the prevalence of RDBs, their use is often required, rather than the more convenient object databases. If this is the case, a number of problems arise due to the mismatch between ...
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