Advantages of a network database model over relational model?

Answer 1

Advantages:

1. Network Model allows each record to have multiple parent and child relationships, unlike the hierarchical model which allows only one parent for each child. This forms a lattice like structure.

Disadvantages:

1. Companies like IBM chose to stick to the hierarchical models.

2. As hardware speed improved, network models were replaced by more powerful models such as the relational model.

Answer 2

The advantage of a network database model is performance and ease of implementing application logic. The disadvantage is lack of flexibility, since the network model impose on you constraints in usage.

Answer 3

The first is efficiency: a network or CODASYL databasewill typically be 1/10 of the size of a RDBMS - representing the same, indexing the same and holding the same data. It will also be many times faster on the "usual" lookup.

BUT

You are stuck with this one way of looking at your data. Like the telephone directory is always sorted according to surname, firstname. Getting a list of people that lives in the same street may take a long time, because the directory is not indexed according to "Street", so you have to search the entire directory.

If a table is always used the same way - that the application logic never change, then the CODASYL / network model is better. This model is made to support this application logic. It supports "sets" of items that match the lines in an invoice, and draws the address with a pointer to the address field in the customer table (here called "realm")

The moment you open for users to make logic and access the data in unpredictable ways, the relational database is superior. If you add a field to a table, the network database must be "reconstructed", while the relational database is designed to do this for you fully transparent. But the flexibility carries a price: performance.