How to avoid duplicate records when update in DB using hibernate

Question

I am updating the record with multiple entries in the db at a time.when i try to create another multiple records, duplicate entries are saved in DB.how to prevent records from duplicates entry using hibernate.i want to restrict 2 or more column value should not equal as before

Answer 1

Defining a primary key, or at least a unique constraint, on the table, is the surest way to avoid duplicates. Then your code will throw some useful errors for you to handle transactions properly.

Answer 2

Define your entity object with Unique Constraints

    @Entity
    @Table(name="user_group", 
              uniqueConstraints = {@UniqueConstraint(columnNames = {"user_id", "group_id"})})
    public class UserGroup implements Serializable
    {

         User user //This is user model
         Group group // This is Group model 
             // Other fields
             // setter and getter methods.

    }

Save the objects within a transaction

 Session session = sessionFactory().openSession();
 session.beginTransaction();
 session.saveOrUpdate(listOfuserGroup);
 session.getTransaction().commit();