Efficient Processing of Databases with Inconsistent Information

Representation and efficient processing of inconsistent information is a common problem for centralized and distributed database systems. While detection of inconsistencies through offline verification of the consistency constraints is a relatively easy task, a complete elimination of inconsistent information from a database as almost impossible. Therefore, database systems should enable the features that allow for the representation and processing of inconsistent information by the user applications. Implementation of such features require the conceptual extensions to both data model and data manipulation language used for the implementation of a database system. This work presents a formal model for the representation and processing of inconsistent information in a database system. Whenever, the contents of a database fails the evaluation of a consistency constraints then the minimal number valid states of the database is represented by the model. Such approach allows for the flexible representation of various sorts of inconsistencies through the relational tables with variants. The model defines a set of operations on the representation of inconsistent information. This work also reviews the implementation aspects of a database system with inconsistent information.