Consistent Query Answering in Inconsistent Databases

These days it is more common to build integrated or federated databases that draw data from multiple, autonomous and distributed sources. The problem of data integration is nevertheless consistent query answering, which is a specific issue arising in data integration. Consistent query answering is an approach to retrieving consistent answers over databases that might be inconsistent with respect t integrity constraints. The approach is based on concepts of repair and query rewriting. This paper surveys several recent researches on obtaining consistent information from inconsistent databases, such as the underlying query rewriting model and a number of approaches to computing consistent query answers