Date Added: Aug 2012
A semantic query is a query pertaining to knowledge or data that is expressed purely on the basis of a common business vocabulary, without any reference to how or where the data is stored. Semantic query refers to database queries that are based on concepts, properties and instances defined in an ontology and that return semantically relevant results. A semantic query attempts to help a user to obtain or manipulate data in a database without knowing its detailed syntactic structure. The alternate query should be semantically equivalent to original query. The semantically equivalent query generated should be less expensive than the original query. These can be implemented in SQL using the SQL hints. These hints allow user to implement the desired plan for the query.