SQL Server: Unique Constraint

Description

A UNIQUE constraint specifies that the values in a column must be unique. This constraint ensures that invalid data does enter the column. A UNIQUE constraint can be applied to multiple columns.

In this lab, you will learn how to add a UNIQUE Constraint to a table in SQL Server.

Based on this Customer and Supplier Schema, generate the solutions to the respective queries listed below:

1. Create a customer table and the ‘Email’ value must be unique.
2. Add a UNIQUE Constraint to the ‘Phone’ Column in an existing Customer table.
3. In the Customer Table, a combination of two columns (LastName, Phone) must be unique.

Lab Objective

Upon completion of this lab, you will be able to:

• Gain Hands-On Experience on SQL Server UNIQUE Constraint.

Prerequisites

• You should have a conceptual understanding of Constraints.
• You must have SQL Server Installed on your systems.