Rajesh Mehta
Rajesh Mehta answered question
Primary key - Primary key means main key def:- A primary key is one which uniquely identifies a row of a table. This key does not allow null values and also does not allow duplicate values. For ex,      empno   empname   salary   1   firoz     35000   2   basha     34000   3   chintoo   40000 it will not the … Read more