Network DBMS

The Network model in DBMS extends the hierarchical model. Remember previously we considered your family tree, but viewed ONLY with respect to your grandmother and her offspring (your father):

The problem is that you have more than one parent. We might better have depicted the relationship as:

This is the basis for the network model. A child can have many parents (well, in this case, two).

Let's consider the Network model from a more practical application: Students taking courses. As we noted earlier, this is a M:M (many-to-many) relationship. For example, there are many students taking this course. Must students are also taking other courses as well. For example, you might presently also be enrolled in Systems Analysis and Design and Accounting Principles. In other words, for a given course, there may be many students and for a given student, there may be many courses (a M:M relationship).

??? So Network models are better than Hierarchical Models ???

Not necessarily. As we said, life is a trade-off: