Hi All,
I have two table one is Event and second is EeventParam, primary key for event is auto generated, which is then used as foreign key in EventParam and there is one to many relationship between these two table.I want to persists objects in these two table in single session.save(Event e) call. but it is giving me ConstarintVailotion exception. After degugging it, i came to know that while peristing EventParam object, its is not able to insert FK which gets from Event table where it is auto generated.Can anybosy tell me the solution for this, how i can get the auto generated key in advance prior to save in DB.

Babu.

It will be better if you post your mapping files.

A simple mapping could be like

<class name="Event" table="EVENT">
<set name="eventParams" cascade="all-delete-orphan">
<key>
<column name="EVENT_ID"/>
</key>
<one-to-many class="zzz.EventParam"/>
</set>
..
..
..
</class>

<class name="EventParam" table="EVENTPARAM">
..
..
..
</class>

See this for more info on collection mapping

http://www.hibernate.org/hib_docs/v3/re ... ollections

Here, I am using hibernate annotation instead of .hbm.xml file,

following are my Event and EventParam entity with their mapping:-

@Entity
@Table(name = "EVENT")
public class Event {
@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "ACTIVITYID")
public List<ActivityParam> activityParam;
@Id
@GeneratedValue
@Column(name = "ID")
private long id;
----
-----------
}
-------------------------------
EventParam.java

@Entity
@Table(name = "ACTIVITY_PARAM")

public class EventParam {
@ManyToOne(cascade = CascadeType.ALL)
@PrimaryKeyJoinColumn(name =EVENTID",
referencedColumnName = "ID")
public Event event;
@Id
@GeneratedValue
@Column(name = "ID")
private long id;
@Column(name = "EVENTID")
private long eventId;
.....
.........

}

Now ,my problem is when i try to persist the EevntParam in DB i have all the attribut from Event except the ID which is foreign key in EventParam,for which my Event entity should be get persist first then the EventParam. Here i am little cofused about the sequence of insert to DB, can you please tell me in which sequence it works, i mean Parent table get inserted first or Child, also give me the solution for above case. Thanks in advance.

Babu

I have never worked with annotations but I think it should be something like:



@Entity
@Table(name = "EVENT")
public class Event {
@OneToMany(cascade = CascadeType.ALL,CascadeType.DELETE_ORPHAN)
@JoinColumn(name = "ACTIVITYID")
public List<ActivityParam> activityParam;
@Id
@GeneratedValue
@Column(name = "ID")
private long id;
----
-----------
}
-------------------------------
EventParam.java

@Entity
@Table(name = "ACTIVITY_PARAM")

public class EventParam {
@PrimaryKeyJoinColumn(name =EVENTID",
referencedColumnName = "ID")
public Event event;
@Id
@GeneratedValue
@Column(name = "ID")
private long id;
@Column(name = "EVENTID")
private long eventId;
.....
.........

}

http://www.hibernate.org/hib_docs/annot ... ec-cascade

I think, you have not understood my problem, i want the auto generated primary key from parent table which is then used in Child table as foriegn key before calling any session.save().

Bb

May be I am missing something. I was just suggesting that hibernate do have a provision where saving a parent object would save all unsaved child objects with proper referential integrity and you do not need to worry about primary / foreign keys.