RDBMS enables you to create databases that can store related data. A database is a collection of information that stores data in database objects, called tables. A table is a collection of related data entries, which consists of columns and rows.
RDBMS enables you to create a link between these tables by establishing a relationship between them. This relational model helps in obtaining related information from multiple tables using SQL. You can see in Figure 11.1 that there are three tables, Employee_Master, Department_Master, and Emp_Dept. All these tables are related with a key field that is called the primary key. In the following example, you can see how the Emp_Dept table, which provides department detail for employees, is linked with the Employee_Master and Department_Master tables:
Figure 11.1: Relation between tables in an RDBMS
In a nutshell, this is how RDBMS co-relates with data stored in tables.