Bitemporal Databases

All mainstream database systems lack support for§temporal metadata, and instead store only the most§recent data. Consequently, they can only manage§temporal data in an ad hoc manner -- oftentimes not§effectively. Yet there are countless application§domains that need temporal data. This book offers a§much-needed solution: It includes a bitemporal§relational data model, based on nested relations, as§well as its algebra and calculus languages for§expressing queries. The fundamental construct for§representing temporal data is a bitemporal atom; a§value, its validity period, and the time this data§was recorded in the database. The concept of context defines different views of bitemporal data.§BtSQL, a simple bitemporal variation of the SQL, is§introduced. The book also provides a prototype§implementation, which demonstrates the feasibility of§the proposed approach in an object-relational§database system. Researchers and practitioners in§database development will find this book useful. It§can be used as a textbook in advanced database§courses -- particularly in application domains where§temporal metadata can greatly leverage the value of§the data as it is stored and utilized.