Database management systems

The terms database and DBMS are often used incorrectly. 

A database contains the data, and the DBMS provides access to this data. The data is independent from the DBMS. 

In a DBMS, data is organised into tables, viewed in forms, retrieved using queries and displayed in reports.   

Storing and retrieving supports all the other information processes; it provides a mechanism for maintaining data and information prior to and after other information processes.  For large data stores, database management systems (DBMS) running on dedicated servers are used.

A DBMS manipulates the data in many different ways, such as sorting and searching. It also performs a number of tasks to help users develop and maintain a database, such as:

• organising the data using a data dictionary

• showing relationships between entities using schematic diagrams

• checking for identifiable errors in data entry

• allowing flexibility to change the definition of the database

• restricting access to the data to authorised people.

• providing information about the performance of the database.

Data Independence

"The separation of data and its management from the software applications that process the data"

DBMS's separate data and its management, including its storage and retrieval, form the software applications that process the data.  The separation of data and processing is known as "data independence"; it provides the ability of data and its organisation to be altered without affecting or changing the software applications that process the data.  

For example, adding new fields to a table or altering the data type or length of a field is performed using the DBMS.  The DBMS not only supplies the data to the software applications, it also supplies the details of how the data is organised.  This means software applications that process this data do not need to be altered, rather they are able to detect the change and adapt accordingly.