This blog shows how to create a unique constraint in a table, Unique constraints are used to enforce a uniqueness to a table some thing related to a primary key. A table can have a single Primary Key to maintain a column uniqueness we can use the Unique constraint as shown below
Syntax:
Create Table tablename
(Column1 Datatype Null/Not Null Primary key,
Column2 Datatype Null/Not Null,
Column3 Datatype Null/Not Null Unique
)
Example:
Create Table emptable
(empid int Not Null Primary key,
empname Varchar(50) Not Null,
empBAID int Not Null Unique
)