A database is an organised pool of logically-related data. Data is stored within the data structures of the database. A DBMS is a suite of computer software providing the interface between users and a database or databases. A DBMS is a shell which surrounds a database or series of databases and through which all interactions take place with the database. The interactions catered for by most existing DBMS fall into four main groups:
- Data Definition. Defining new data structures for a database, removing data structures from the database, modifying the structure of existing data.
- Data Maintenance. Inserting new data into existing data structures, updating data in existing data structures, deleting data from existing data structures.
- Data Retrieval. Querying existing data by end-users and extracting data for use by application programs.
- Data Control. Creating and monitoring users of the database, restricting access to data in the database and monitoring the performance of databases.
Both a database and its DBMS conform to the principles of a particular data model. Data models include the hierarchical data model, the network data model, the relational data model and the object-oriented data model.
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