Components of Database Systems

Components of Database Systems are;

• Data
• Hardware
• Software
• Database users

DATA

Data is a collection of meaningful facts or figures expressed in a form that its users could understand. It can be recorded and processed for further use. The Data stored in the system is portioned into one or more databases. Generally we assume that there is just one database, containing totality of all stored data in the system.

Data stored in the database is both integrated and shared

Integrated: The data is accurate, consisted and up to date - because each updating change is made only in one place.

Shared: Individual pieces of data in the database can be shared among different users, in the sense that each of those users can have access to the same piece of data, which can use for different purposes. The same piece of data can be effectively access by different users at the same time that is Concurrent Access. Sharing of dta, concurrent or otherwise, is partly a consequence of the fact that the database is integrated.

HARDWARE

The hardware components of the system consist of :

• The secondary storage volumes - mostly magnetic disks - that are used to hold the stored data, together with the associated I/O devices (disk drives,etc.), device controllers, I/O channels.

• The hardware processor and associated main memory that are used to support the execution of the database system software.

SOFTWARE

A software act as an interface between the physical database itself-i.e., the data as physically stored - and the users of the system. Data base management system (DBMS) software or Data base manager, a program that controls structure of a database and access to the data. All requests for access to the database are handled by the DBMS. For adding and removing files, retrieving data from and updating data in such files or tables, and so forth, are all facilities provided by the DBMS.

DATABASE USERS

A primary goal of a database system is to provide an environment for retrieving information from and storing information into the database.

Any entity whether a human or a software system that interacts with a database is known as a database user. However, the role of a user with respect to a database depends on the responsibilities it carries and the operations  it performs on the database. Accordingly, following classws of users exist in a database system:

• Database Administrators (DBA): The user is responsible for creating. manipulating and authorizing access to the database. They are also responsible for coordinating and monitoring its use. A DBA has complete control on every aspect of the database. Sometimes a DBA is also called as Super-User.

• Database Designers: They are responsible for identifying the data to be stored and foe choosing appropriate data structures to represent and store this data.

• End User: People whose jobs require access to the database for querying, updating, and generating reports are end-users. They carry out their jobs either through application programs or users programs.

• System Analysts: System analysts determine the requirements of the end users, and develop specifications for transactions.

• Application Programmers: Application pragrammers implement specifications and programs developed by the analysts so that the specification becomes perational. The application program are written in the host language for example Pascal, C++, Cobol. Analysts and programmers nowadays are called software engineers.