L-Base is a tightly coupled Prolog and Relational Database System. It integrates Arity Prolog and DBase III+. The advantages of L-Base can be grouped into two main categories: data organisation and data semantics. Prolog’s structure flexibility offers space saving because of variable record length. Records are organised in lists allowing both tuple- and attribute- oriented queries. Data dependencies are organised in list-fields within records. Prolog offers fast data retrieval due to efficient indexing through b-trees. Hash tables and buckets reduce the size of data to be searched offering a powerful data modelling tool. Data semantic advantages of Prolog arise from the use of facts, which behave as actual data, and rules, which compute data at the querying time. The result is the ability to extract more meaning from the data without distracting the data file’s structure. Prolog offers a sophisticated inference engine that allows complicated logic queries.
