SQL_Identity_key.sql

/*

Author : Jaydatt Patel

Identity key:
When a table column is defined with an identity 
property, its value will be auto-generated incremental 
value. This value is created by the server automatically. 
Therefore, we can't manually enter a value into an identity 
column as a user. Hence, if we mark a column as identity, 
SQL Server will populate it in an auto-increment manner.

syntax:   IDENTITY[(seed, increment)]  

Seed: It indicates the starting value of the row loaded 
		into the table. By default, its value is 1.
Increment: It indicates the incremental value, which is 
		added to the identity value of the last loaded row. 
		By default, its value is 1.
*/

create table student
	(	
		id int IDENTITY(1,1) primary key, 
		firstname varchar(20) not null,
		lastname varchar(20),
		dob date,
		result int,
		city varchar(20),
		gender varchar(8) 
	);


/*insert multiple records.*/
insert into student values('Rahul','Shah','01-dec-1990',85,'Ahmedabad','M');
insert into student values('Riya','Shah','09-may-1995',70, 'Ahmedabad','F');
insert into student values('Rekha','Kapoor',NULL,40,'Ahmedabad','F');
insert into student values('Amit','Verma','03-oct-1992',90,'Delhi','M');
insert into student values('Khushi','Patel','15-apr-1993',NULL,'Bangalore','F');
insert into student values('Hitesh','Sharma','04-aug-1980',56, NULL,'M');
insert into student values('Mital','Kumawat','22-jul-1970',95, 'Mumbai','F');
insert into student values('Jay',NULL,'16-feb-1975',60,'Mumbai','M');
insert into student values('Tanvi','Dave','18-sep-1977',70, 'Chennai','F');
insert into student values('xyz',NULL,'12-jun-1994',NULL,'Mumbai',NULL);

select * from student;