Lookup Table - mapping class property to another table

wongbego · **Joined:** Wed Dec 07, 2005 8:20 am **Posts:** 10

Hi all,

I'm a newbie and have following problems.

I use Many to One association but I don't want to have 2 Different Objects

Let me use the example on the Reference Doc Chapter 8.2.1, with some modification

Tables:

create table Person (
personId bigint not null primary key,
name VARCHAR(50),
addressId bigint not null REFERENCES Address (addressId)
)

create table Address (
addressId bigint not null primary key,
street VARCHAR(50)
)

I want to have only Person Object

Class Person{

private Integer personId;
private String name;
private String street; //no Address Object association
...
}

the uncomplete mapping file:
<class name="Person">
<id name="id" column="personId">
<generator class="native"/>
</id>
<property name="name" column="name" type="string" not-null="true"/>


<property name="street" type="string" not-null="true"/>

</class>

The Address Table is just a Lookup table with 1 column of VARCHAR....

If I follow the NORMAL many to one association, then I have to create an Object fo every LOOKUP Table, and then map the Object as Attribute of the Class. Somehow I believe that this is too complicated to write, specially if you have dozens of lookup table value....

Can this be done in Hibernate??

I tried the <JOIN> element, but no success, specially because the JOIN element's KEY needs that there is a foreign key IN the ADDRESS table, which reference to the PK of the PERSON Table, but on my case the PERSON TABLE have a FK to the ADDRESS TABLE.

Thank you very much for your help.

ljnelson · **Posted:** Fri Dec 30, 2005 1:30 pm

Have you found a solution for this? I posted the same topic, and no one could answer it either.

Thanks,
Laird

wongbego · **Joined:** Wed Dec 07, 2005 8:20 am **Posts:** 10

Nope...

I rearrange my mapping, and try to use different schema

fedora · **Joined:** Fri Jan 06, 2006 10:22 am **Posts:** 1

Unfortunately in my case, the mapping table is more like an enum. It looks sort of like this:

Code:

create table item (
id int,
color_id int,
...
)

create table color_lookup (
id int,
color char(20)
)

I would like to be able to have the Item bean simply have a color property that is a simple string (i,e,,

Code:

public class Item {
  public String getColor()
  {...}
...
}

), since the colors are seldom updated (we will do that by hand with an SQL insert). On the other hand, they will be updated often enough that I don't want an enum and a recompile every time we do...
Any ideas?

Fedora

Factor Three · **Joined:** Fri Dec 30, 2005 10:51 am **Posts:** 3

Actually, you folks aren't the only ones with this problem.

I have to use a schema that I cannot change (is "imposed" on me), and I need to have an object with some string anfd integer properties that map to two different tables.

I have been studying documentation and Hibernate books for quite some time; there is plenty on Joins and plenty on associations, but nothing anywhere that speaks of this particular situation.

Have we found a Hibernate limitation? Or are we missing something?

Does anyone have an answer to this question???

max · **Posted:** Fri Jan 06, 2006 1:51 pm

<join>

wongbego · **Joined:** Wed Dec 07, 2005 8:20 am **Posts:** 10

<join> is not what I want... since I wrote it that it didn't work

and the end... I create a Class for the all attribute.
The Class is then mapped to the lookup table...

works well... :-)