Question

Heya!!!❤❤❤ Please answer my question and clear my doubt

My Question is... 20 (b)...

Answer 1

Primary key:

(1) It doesn't allow duplicated and null values.

(2) It is a combination of UNIQUE and NOTNULL.

(3) Can be declared for combination of columns then it is called as composite primary key.

Sample Program in SQL:

(i) Create table Demo(Deptno varchar(10) constraint con Primary key, Department_name varchar(12), Name varchar(10), City varchar(10));

(ii) Select * from Demo;

(iii) insert into Demo values('S1003', 'Sales','Sameer', 'Patna');

Hope it helps!