SQL 001 What is a Relational Database, DBMS, or RDBMS?

A database is a collection of data with common record formats making a file with many different records. Other files with different record formats make up a system. For example, you have a company with employees and you must run a payroll system to pay these employees. The employee file contains the Employee ID, Name, Address, Rate/Hour, etc. If you append the Pay Date, Hours Worked, Gross Pay, etc., then you can produce payroll checks and pay your employees.

For the next pay period, you would be able to duplicate each record on your employee file.

This method will work fine for a small company, but you can see that there is a duplication of much of the data, such as Employee ID, Name, Address, Rate/Hour, etc. This is called Data Redundancy.

If you have an employee file and a payroll file, then you must read two files to produce payroll checks, but most of the data redundancy has been eliminated — requiring much less data-storage space. Because there is less data to read, the processing may go faster.

Database systems manage the data by adding, updating, and deleting data, as well as sorting, doing calculations, and generating reports.

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