The use of a database for data storage, maintenance, and interrogation. The term is used especially to distinguish this “normal” use of databases from the more specialized online analytical processing, and also to distinguish the differing designs appropriate for each use. A basic rule of OTLP databases is that data should not be duplicated in any way. This ensures data consistency and efficient update, but causes complex analytical queries to perform slowly because all aggregates much be recomputed every time. Today most OLTP databases use the relational database model.