Hi there, I have what I think should be a simple problem, which is causing me to bang my head against the wall.

The scenario is this, I have two tables:



Now, what I would like to have is one object:

I would like a Mapping document for A such that there is a join between TABLE_A and TABLE_B where TABLE_A.REF_LOAN_NUM = TABLE_B.LOAN_NUM. I know this database schema is a$$, but I didn't design it! I just have to live with it.

Anyone have any clue how I might do this? I thought I could get away with adding this entry to the mapping document:



However I soon realized that "property-ref" doesn't accept a column name.

Thanks.

Might be worth a look:

http://forum.hibernate.org/viewtopic.php?t=976874

Also, if that doesn't help you, look at page 98 of the hibernate_reference pdf :

7.6. More complex association mappings

This allows you to define an arbitrary property element and then use that as the property-ref

Hi if you get an idea how to resolve this kind of issue please let me know thank you

Nope, I just can't seem to figure this out! I think part of the problem is, sometimes with hibernate mappings it's tough to figure out the context of some of the mapping elements.

For instance, why would I not be able to specify a *column* name for a reference in the foreign table? Like:

<key column="REF_LOAN_NUM" foreign-ref="LOAN_NUM"/>

I don't know, I'm really finding Hibernate good for simple mappings, and confusing as he11 for anything else. But, obviously others are able to figure this type of thing out, so it is probably just me.

All I want to do is have a class which gets some of it's properties from another table via a join. I can't seem to do that when the join column in TABLE_B is not it's primary key. In theory, the join column should be it's primary key, in reality people creating and adapting schema's "cheat".

If anyone else has any ideas please let me know

I managed to solve my problem using an <sql-query> tag defining a full SQL statement with join (iBatis-type approach). I guess the other way would be to use a view.

Hi craiger316,
You are right. As I searched over the internet, don't know why Hibernate doesn't provide easy way to mapping for these type of many-to-many association.


As you said, I hope you can below peice of exapmle..

<class name="Person">
<id name="id" column="personId">
<generator class="native"/>
</id>
<set name="addresses" table="PersonAddress">
<key column="personId"/>
<many-to-many column="addressId"
class="Address"/>
</set>
</class>

<class name="Address">
<id name="id" column="addressId">
<generator class="native"/>
</id>
</class>

create table Person ( personId bigint not null primary key )
create table PersonAddress ( personId bigint not null, addressId bigint not null, primary key (personId, addressId) )
create table Address ( addressId bigint not null primary key )


Only thing you have to create a view to create join table like PersonAddress.

Regards
Shanmugam.N