Architecture

Data Definition

No accepted standard data definition language exists for OODB's instead programmers create the object classes in the O-O implementation language, such as C++ or Java, (figure 2).

Relationships can be exhibited in schema by including a data property, known as a pointer, in an object that points to the related object (figure 3).

Changing the schema would require amending and recompiling the class definition.

Navigation

An OODB may be comprised of a small to large number of objects. Searching for a particular object, by pointer, is carried by navigating from object to object (figure 4).

This approach is considered more natural to object searching than the algebra method used in relational databases.

Data Manipulation

The standard query language for OODB's is the Object Query Language (OQL). OQL takes certain features from SQL (i.e. full SELECT statement) and adds object-oriented extensions. Designed to work with objects, it lacks specify features UPDATE instead invoking the object operators to modify the state of the object. It is possible to modify objects and create new persistent objects through OQL statements [Riccardi 01]. Figure 5 shows the OQL statements for the processes described in figure 4.

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