<p>query in a database system can fail for many reasons, including lack of available data, user error, or conflict between the query and the database semantics. Furthermore, conventional Database Systems (DBS), in most cases, do not incorporate facilities to detect the user intention behind a query. These database systems are therefore not able to provide additional information beyond an answer to a query. While additional or alternative information may not match a query semantically or grammatically, it is often required to support decision-making and to assist in carrying out actions. It is therefore very desirable to develop a mechanism that takes into account factors like user errors, user interests or intention, to prevent a query from failing and to facilitate the retrieval of alternative and relevant information which includes more than the basic answers to an original question.</p>