Relational Database: It is a database which maintains a set of separate, related files (that is, tables), however combines data elements from the files for queries and reports whenever needed. The concept was introduced in the year1970 by Edgar Codd, whose purpose was to accommodate a user's ad hoc request for chosen data. Mostly in every business database management system (abbreviated as DBMS), comprising Oracle, SQL Server, DB2, MySQL, and so on, is a relational DBMS (abbreviated as RDBMS).