But when they were first introduce d, programmers tried to make relational products behave exactly as a file system. It can be done, but at fantastic performance cost. We needed a paradigm shift to appreciate the power of a relational system. No one really wants to do that again with object databases. The term should have been objectbase instead of object database , because the goal is not to store, manipulate, and retrieve data within an object, but to store, manipulate, and retrieve objects themselves.
Relational databases allow elaborate queries on simple data.
Pure object databases allow relatively simple queries on complex data. The difference is that the objects are added as an afterthought or a shell around the database rather than integrating them into the database engine. If you cannot tell the query optimizer, the indexing, and the database-engine functions how to handle the new data types invisibly to the user, they are not integrated. IBM and Oracle have object-relational offerings for their relational databases. It can be assembled again in the morning, but one eventually asks whether this is the most efficient way to park a car.