RDBMS INTO

A Database Management System (DBMS) is software used to store and manage data. A DBMS stores data in databases and uses data models to show the various ways of managing data. A Relational Database Management System (RDBMS) is an advanced version of a DBMS that also defines the relationship between the various data values. This feature helps in managing and using data more efficiently than DBMS. This chapter introduces DBMS and describes the various types of data models. It explains the most widely used entity relationship model and discusses the various types of relationships among the entities. In addition, the chapter describes the various ways of accessing data by using relational operators and joins.

Database Management System

A database is a collection of logically related data. Data means known facts, which are meaningful and can be recorded. For example, names, telephone numbers, and addresses.

    DATA MODEL

A data model is a description of the data in a database. In addition, the data model describes the relationship among data, and any constraints that have to be defined on the
data. Data models can broadly be classified into the following categories:

Object- based logical model : Focuses on describing the data, the relationship among the data, and any constraints defined.

 Record- based logical model : Focuses on specifying the logical structuring of the database in the form of tables.