Field with autoincrement is very useful thing and it's often used in MySQL. In MSSQL you can also need to use this tool. There are two ways to do it.

1. From code

If your table still doesn’t exist:

 

If your table already exists:

2. From GUI in Microsoft SQL Server Management studio

Column "id" must be INT type, not nchar or any other.

Column "id" must be INT type, not nchar or other.

Column "id" must be INT type, not nchar or other.

 

In Column properties set in "Identity Specification" for property (Is Identity) value "Yes".

Identity Specification