How to set read-only columns in Hibernate?

Question

I don't know how to force read-only columns in Hibernate.

I would like to set idgroup as read only column. Even if I set insertable=false and updatable=false, in the hibernate SQL I can read:

Hibernate: insert into groups (description, name, account_idaccount, idgroup) values (?, ?, ?, ?)

but I would like to obtain:

insert into groups (description, name, account_idaccount) values (?, ?, ?)

Here are my classes:

@Entity
@Table(name = "groups")
public class Group implements java.io.Serializable {

private static final long serialVersionUID = -2948610975819234753L;
private GroupId id;
private Account account;
private String name;
private String description;

@EmbeddedId
@AttributeOverrides({@AttributeOverride(name = "idgroup", column = @Column(name = "idgroup", insertable = false)),
        @AttributeOverride(name = "accountIdaccount", column = @Column(name = "account_idaccount", nullable = false))})
public GroupId getId() {
    return id;
}

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "account_idaccount", nullable = false, insertable = false, updatable = false)
public Account getAccount() {
    return account;
}

@Column(name = "description", length = 512)
public String getDescription() {
    return description;
}


@Column(name = "name", nullable = false, length = 128)
public String getName() {
    return name;
}
..
}

@Embeddable
public class GroupId implements java.io.Serializable {

private int idgroup;
private int accountIdaccount;

@Column(name = "idgroup", insertable= false, updatable= false)
public int getIdgroup() {
    return this.idgroup;
}


@Column(name = "account_idaccount", nullable = false)
public int getAccountIdaccount() {
    return this.accountIdaccount;
}
..
}

I would like to have a read only column for idgroup because I can exploit the id auto-generation of the DBMS, I do not want to use the key auto-generation in Hibernate because it is not cluster-safe.

have a look at http://docs.jboss.org/hibernate/orm/3.5/reference/en-US/html/readonly.html and http://ndpsoftware.com/HibernateMappingCheatSheet.html - they may give you hints — Rachel Gallen, Jan 31 '13 at 13:07
thanks Rachel, but the first link refers to read only entities, and I don't see the second useful to my case — cloudy_weather, Jan 31 '13 at 13:19
Is it good for you if hibernate instead of not trying to persist your readonly value just persist always the same what he collected when getting entity from dbms? — Michał Kupisiński, Jan 31 '13 at 14:02
the problem is when I create an instance from Java and I want to save it in the database, even if I don't initialize the idgroup, hibernate writes 0 because it is the default value for int. — cloudy_weather, Jan 31 '13 at 15:04
This wasn't tagged with JPA, but my guess is you will need to specify a SequenceGenerator to get it to use your database's sequencing, otherwise it will not be usable in relationships etc. You are also overriding your column to only be insertable=false - someone else suggested it be marked both insertable+updatable=false — Chris, Feb 01 '13 at 19:16

score 15 · Answer 1 · edited Feb 20 '17 at 08:17

15

I think you can mark an @Column annotation as updatable=false

edited Feb 20 '17 at 08:17

naXa stands with Ukraine

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answered Jan 31 '13 at 13:05

Bob Flannigon

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already done, if you read the code above in GroupId.getIdgroup() – cloudy_weather Jan 31 '13 at 13:07

score 6 · Answer 2 · edited Apr 13 '21 at 19:04

6

Easy:

@Column(insertable = false, updatable = false)

edited Apr 13 '21 at 19:04

naXa stands with Ukraine

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answered Mar 03 '19 at 00:46

J. Jerez

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consider adding more information as to how this solve's the problem for OP – Inder Mar 03 '19 at 01:28

score 0 · Answer 3 · answered Dec 02 '19 at 14:35

I was able to achieve this by using 2 DAO objects. I know it may not be preferred, but I didn't see another way around it. Setting the field to insertable=false and updatable=false do not remove the columns from the insert SQL so Postgres will not invoke the default action to populate those column values.

   // GroupWrite

   @Entity
   @Table(name = "group")
   public class GroupWrite {

      @Id
      @Column(name = "account")
      private Account account;

      @Column(name = "name")
      private String name;

      @Column(name = "description")
      private String description;


      /* Getters and Setters */
  }

--

   // GroupRead

   @Entity
   @Table(name = "group")
   public class GroupRead {

      @EmbeddedId
      @Column(name = "id")
      private GroupId id;

      @Column(name = "account")
      private Account account;

      @Column(name = "name")
      private String name;

      @Column(name = "description")
      private String description;


      /* Getters and Setters */
  }

Then you need to use the GroupRead when using select queries and GroupWrite when doing insert or update queries.

If you want to use attributes from both in a common way you can implement an interface that describes the overlapping fields.

   public interface Group {

        Account getAccount();

        void setAccount(Account account);
   }

   public class GroupWrite implements Group {...}

   public class GroupRead implements Group {...}

Hope this helps.

score -2 · Accepted Answer · edited Dec 18 '16 at 10:44

-2

The solution is using wrapper classes, such as Integer, not primitive types like int. When Hibernate will get a null pointer it will delegate the generation of the id to the DBMS.

edited Dec 18 '16 at 10:44

try-catch-finally

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answered Feb 18 '13 at 13:49

cloudy_weather

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score -3 · Answer 5 · answered Aug 18 '15 at 09:14

-3

@ReadOnlyProperty annotation will help you in this case.

answered Aug 18 '15 at 09:14

Rakesh

1

It's always useful to add an explanation on *how* would things help. – Tavo Aug 18 '15 at 09:41
1

It didn't help me. At least the one I found, which was org.springframework.data.annotation.ReadOnlyProperty. I didn't find a Hibernate property by that name. – MiguelMunoz Feb 13 '18 at 20:35

How to set read-only columns in Hibernate?

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