UNIQUE - ERDL Diagram Syntax

• Use UNIQUE keyword to specify the column is unique
• To define a composite UNIQUE constraint, use the table level UNIQUE() syntax

Order
-
OrderID int UNIQUE
CustomerID int
 TotalAmount money
OrderStatusID int

(or)

Order
-
OrderID int
CustomerID int
TotalAmount money
OrderStatusID int
UNIQUE(OrderID, CustomerID)