A shared collection of logically related data (and a description of this data), designed to meet the information needs of an organization.
The database is a single, possibly large repository of data, which can be used simultaneously by many departments and users. All data that is required by these users is integrated with a minimum amount of duplication. And importantly, the database is normally not owned by any one department or user but is a shared corporate resource.
A software system that enables users to define, create, and maintain the database and also provides controlled access to this database.
The DBMS is the software that interacts with the users, application programs, and the database.
Among other things, the DBMS allows users to insert, update, delete, and retrieve data from the database. Having a central repository for all data and data descriptions allows the DBMS to provide a general inquiry facility to this data, called a query language. The provision of a query language (such as SQL) alleviates the problems with earlier systems where the user has to work with a fixed set of queries or where there is a proliferation of programs, giving major software management problems.
A DBMS is usually an inherent part of a database product. On PCs, Microsoft Access is a popular example of a single- or small-group user DBMS. Microsoft’s SQL Server is an example of a DBMS that serves database requests from multiple (client) users. Other popular DBMSs (these are all RDBMSs, by the way) are IBM’s DB2, Oracle’s line of database management products, and Sybase’s products.