Hibernate annotation OnetoOne relationship

Question

I have a critical issue. I have a table

TICKETINFO

TICKETINFOID pk, REMARK varchar(128), TICKETDATE timestamp

it has a corresponding class with hibernate annotation which somewhat looks like this

@Entity
@Table(name = "TICKETINFO")
public class Ticketinfo implements Serializable {

    @Id
    @Column(name = "TICKETINFOID")
    private Long id;
    @Column(name = "TICKETDATE")
    private String date;
    @column(name = "REMARK")
    private string remark;

    //getters and setters
}

now my work is that i need to create a child table of TICKETINFO table

TICKETINFO_REMARK

TICKETINFO_REMARK_ID pk, TICKETINFOID fk, REMARK varchar(128)

and TICKETINFOID will be foreign key from TICKETINFO table and have to populate the REMARK field of TICKETINFO_REMARK along with the REMARK field of TICKETINFO for the corresponding TICKETINFOID.

For 1 TICKETINFOID there will be one REMARK and it could be null. The datatype of REMARK in Ticketinfo.java have to keep it as string.I can add extra logic but cannot change the existing flow.

Please help me as I am in a terrible mess....

So there's no such column as TICKETINFO.REMARK? You can't map it as `@Column` on Ticketinfo class then. Typically you'd have a separate entity class TicketinfoRemark that will be linked up to Ticketinfo via a `@OneToOne` annotation. You could probably add an accessor in Ticketinfo: `String getRemark() { if (ticketinfoRemark != null) return ticketinfoRemark.remark; }` but this is a hack. — maksimov, May 29 '12 at 10:14
possible duplicate of [Create and populate child table from Parent table using Hibernate Annotation](http://stackoverflow.com/questions/10784891/create-and-populate-child-table-from-parent-table-using-hibernate-annotation) How about reading the answer you got the first time you posted this question? — JB Nizet, May 29 '12 at 11:21

score 0 · Answer 1 · answered May 29 '12 at 10:10

It sounds like a One-To-One would do the trick for the linking up of the child table. For the remark itself, you'll probably want to hijack the accessors and mutators as I don't think Hibernate handles what you want out of the box. If you have something as an attribute of another table, faking it this way isn't orthogonal or best practice. If you can't change it, leave it as it is unless you have a VERY good reason for writing weird fudges into your code.

score 0 · Answer 2 · edited May 29 '12 at 12:11

You can make REMARK field as @Transient and use @PreUpdate @PrePersist and @PostLoad methods to load and save remark field from/to one-to-one mapped TICKETINFO_REMARK entity. The same could be done on TICKETINFO_REMARK side.

Here is quick example, it is not tested, just to give you an idea.

@Entity
@Table(name = "TICKETINFO")
public class Ticketinfo implements Serializable {

    @Id
    @Column(name = "TICKETINFOID")
    private Long id;
    @Column(name = "TICKETDATE")
    private String date;
    @Transient
    private string remark;
    @OneToOne
    @PrimaryKeyJoinColumn
    private TicketinfoRemark ticketInfoRemark;

    @PostLoad
    public void postLoad() {
        if (ticketInfoRemark != null)
            this.remark = ticketInfoRemark.getRemark();
    }

    @PreUpdate
    @PrePersist
    public void prePersist() {
       if (ticketInfoRemark != null)
           ticketInfoRemark.setRemark(this.remark);
    }
    //getters and setters
}

Hope it helps.

Well...I am new to Hibernate...so could you pls write the class for me....like how will be the OnetoOne syntax will look like in Ticketinfo.java — saptarshi, May 29 '12 at 10:22
Updated post with example, please sorry if it not works, I could not test it right now. — Alexey Ogarkov, May 29 '12 at 10:28
Alexey, you must check for `null` where you access ticketInfoRemark field. — maksimov, May 29 '12 at 10:47

Hibernate annotation OnetoOne relationship

TICKETINFO

TICKETINFO_REMARK

2 Answers2