A methodology for the design and implementation of a functional object database using Haskell

Semantic data modelling has been a traditional abstract way of representing data and relationships between data for database systems. Recently database designers and developers have been looking to object oriented modelling methods which incorporate the modelling of behaviour as well as data and their relationships. Databases can also be considered to be functional structures. All operations on databases are functional in that they return values. Transaction and update operations return a new version of the database; queries return values contained in the database; and reports return values from the database in some strictly formatted form. This thesis firstly develops an extended version of the Entity-Relationship model, called the Entity-Relationship-Object model (ERO model) that incorporates object oriented concepts including behaviour. Secondly, a methodology is defined for mapping this model directly to the functional. . programming language, Haskell, where all Entity and Relationship objects are implemented as abstract data types and all attributes and methods are implemented as functions. The modularity and polymorphism of the proposed models and their implementation allow for easy schema extension and modification. Lazy evaluation in the implementation allows for a simple form of persistent data store.