@UniqueConstraint annotation in Java

Question

I have a Java bean. Now, I want to be sure that the field should be unique.

I am using the following code:

@UniqueConstraint(columnNames={\"username\         


        

Answer 1

   @Entity @Table(name = "stock", catalog = "mkyongdb",
   uniqueConstraints = @UniqueConstraint(columnNames =
   "STOCK_NAME"),@UniqueConstraint(columnNames = "STOCK_CODE") }) public
   class Stock implements java.io.Serializable {

   }

Unique constraints used only for creating composite key ,which will be unique.It will represent the table as primary key combined as unique.