A collection of data arranged for ease and speed of search and retrieval.

More often than not, a database is made up of one or more 'tables' of data, and relationships can be defined between these tables - for instance you could have one table called contacts containing the names of people in an address book, and another called phones containing their various phone and fax numbers. Both of these tables would have to identify who the information was about, and so would have the identifying piece of information in common. This commonality is known as a relationship. From this we get Relational Database Management Systems (RDBMS).

Examples include Oracle, MySql?, PostgreSQL, Microsoft SQL Server, Informix, Borland Interbase, FireBird and IBM DB2.

See PostgresVsMysql