Databases and database systems have become an essential part of our daily life. We encounter many activities that involve some interaction with a database almost daily. The examples include withdrawal from a bank and/or deposit, hotel, railway reservation or airline, accessing a computerised library, order a magazine subscription from a purchase items, publisher from supermarkets. In all the above given cases a database is accessed. These may be known as Traditional Database Applications. In these kinds of databases, the information stored and accessed is numeric or textual. Though, with advances in technology in the past few years, dissimilar databases have been developed such as Multimedia Databases that sound messages, store pictures, and video clips,; Geographical Information Systems (GIS) that can store maps, satellite images, and weather data etc., and Real time databases that can control industrial and manufacturing processes. In this section, we will be introducing the concepts involved in the Database Management System.