Differentiate all basic and alternative database models:
Hierarchical- this is a tree structured model for a database. It requires that the application knows about the physical relationships between entities. The structure is rigid. IMS is a hierarchical database.
Network- an extension of the tree into a lattice so that multiple relationships can be supported. The CODASYL standard defines features for network databases. This model is inflexible, requiring significant changes if relationships change. IDMS is a network database.
Relational- this model is based on relational algebra and encompasses the rules developed by Codd. Most of the databases in commercial use now are relational, e.g., Sybase, Oracle, Ingres. The model is flexible and extensible.
Object- object databases address the need to store more complex data types than are supported by the relational model.