136 страниц. 2013 год. LAP Lambert Academic Publishing As we all know Database has a availability of a storage system, the most obvious of these being persistence. To sum it up, we can identify the following reasons for wanting a Database Management Systems short for DBMS: 1.We need to share data of all kinds between users (except for very small systems), between tools working on them, and usually between different computers. All should be able to work with the same set of data. 2.We need persistent storage and storage must be reliable. 3.Several users and/or several tools must be able to safely access the same data concurrently. 4.A DBMS may provide more efficient access to large amounts of data, through indexing and other optimizations. 5.A DBMS and its data model provides an abstraction; we do not need to care about the physical storage format. 6.A DBMS may also be used for communication between different users or applications.