Hibernate saving duplicate

Question

I have a Many-To-One relationship between two table in my database User table & Country table. The model classes are:

@Entity (name = "user")
 public class User {

      @Id @GeneratedValue (strategy = GenerationType.IDENTITY)
      private int userId;
      private String username;
      private String password;

      @ManyToOne (cascade = {CascadeType.ALL})
      @JoinColumn (name = "countryId")
      private Country country;

     //Getter & Setter
 }


  @Entity (name = "country")
  public class Country {

      @Id @GeneratedValue(strategy = GenerationType.AUTO)
      private int countryId;
      private String countryName;
      //Getter & Setter
 }

The problem I am having is when I save a new User object it also saves a new country record even when that country already exist in the database. How can I solve this problem?

Rohit Jain · Accepted Answer · 2013-06-24 20:17:18Z

3

You can try changing the cascade type in the @ManyToOne relationship:

@ManyToOne (cascade = CascadeType.MERGE)
@JoinColumn (name = "countryId")
private Country country;

When using CascadeType.ALL, it also includes, CascadeType.PERSIST, in which case, the persist operation is cascaded to Country whenever your persist User.

answered Jun 24, 2013 at 20:17

Rohit Jain

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3 Comments

Mario Dennis Over a year ago

This create a new problem. It's not saving the object now

Rohit Jain Over a year ago

@MarioDennis. Can you try removing the cascade completely.

Mario Dennis Over a year ago

When I remove it I get: org.hibernate.HibernateException: Data was not saved: object references an unsaved transient instance - save the transient instance before flushing: com.kyrogaming.models.Country

Serhii Shevchyk · Accepted Answer · 2013-10-31 21:58:58Z

0

As far as I understand Country table is like dictionary and in most cases you should't save it every time you save an entity. Why do you need to save it by cascade?

If you really have to update Country why wouldn't it be done before saving User instance?

Using CascadeType.ALL is not really good because you will loose Country when you delete User.

answered Oct 31, 2013 at 21:58

Serhii Shevchyk

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