Database technology has improved over the issues of organizing data with traditional file systems. Rather than
storing data in separate files for each application, data are stored physically to appear to the user as being
stored in only one location. A database is a collection of data organized to serve many applications efficiently
by centralizing the data and minimizing redundant data. A single database services multiple applications. For
example, instead of a corporation storing employee data in separate information systems and separate files for
personnel, payroll, and benefits, the organization could create a single common Human Resources database
to integrate all of those functions and processes.
A database management system (DBMS) is the software that allows the organization to centralize data,
manage them efficiently, and provide access to the stored data by application programs. The DBMS acts as
the interface between application programs the physical data tables. A database management system has
three components: a data definition language, a data manipulation language, and a data dictionary.