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mapping three tables

sammeta Phanikumar
Ranch Hand

Joined: Oct 25, 2007
Posts: 81
Hi Friends,

I am new to ORM/hibernate please help in this.

I have the follwoing table structure.

Table_A: (a_Id [PK], a_Desc)
Table_B: (b_Id [PK],b_Desc)

These two tables hbm files are working fine.

Now I want to have a mapping table description as below.

Table_Mapping( b_Id [PK], a_Id, mapping_Desc)

Here I want B table primery key b_Id as forieng key to Table_Mapping. And when an entry in Table_Mapping is removed it should not effect any way in either of A and B tables.

Please help in this.

I have found some example on google, but they say keep an instance of Table_Mapping entry in Table_B.hbm, But why like that.

It is all mapping table have reference of other two tables, these two tbales do not know any thing about Mapping. I think they need not to know.

Please help me to understand this, if am wrong.

I appreciate a quick response.

Thanks in advance.

SCJP 5, SCWCD 5, SCDJWS 5
Ravishanker kumar
Ranch Hand

Joined: Jul 20, 2006
Posts: 53
It will be better if you can provide relation between objects A,B and Mapping.
for A and B,


what about third one?
sammeta Phanikumar
Ranch Hand

Joined: Oct 25, 2007
Posts: 81
Thanks Ravi for your reply,

Here are the details.



These two classes are working fine because there are opereated independent.

Now I want a third class Mapping. Relation between A and B are: A -> B(many to one) and B->A(One to One)

class Mapping
{
int a_Id;
int b_Id;
String mapping_Desc;
}

I want add/deletion in Mapping table should not reflect in either of Table A and B.
But for any entry in Mapping then Mapping->a_Id ,a_Id should be in Table_A and Mapping->b_Id ,b_Id should be in B table.

Please reply.

sammeta Phanikumar
Ranch Hand

Joined: Oct 25, 2007
Posts: 81
Hi,

Please reply any one, if the problem is not clear, let me know i will explain.

 
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