[rtosi]

Hi,
I’ve a problem with foreign keys:

I have a table Resources like this : rid (pk) – cid – rname

I’have to create another table like this : did (pk) – dep- rid1 (fk) -rid2(fk)

I have 2 EJB-CMP : ResourcesBean and DepBean for the first and the second table. In ResourceBean I have getRid() and setRid().

In the DepBean I have to use setRid1() and setRid2().
For getter and setter rid1 I have :
/**
* @ejb.relation
* name=”did-rid1″
* role-name=”dep-has-rid1″
* target-ejb = “Resource”
*
* @jboss.relation related-pk-field = “rid”
* fk-column = “rid1″
*
*
*
*/
public abstract ResourceLocal getRid1();

public abstract void setRid1(ResourceLocal c);

…and for rid2 ???

I can’t use :

/**
* @ejb.relation
* name=”did-rid1″
* role-name=”dep-has-rid1”
* target-ejb = “Resource”
*
* @jboss.relation related-pk-field = “rid”
* fk-column = “rid2”
*
*
*
*/
public abstract ResourceLocal getRid2();

public abstract void setRid2(ResourceLocal c);

….beacuse there is the same role-name and the same name…..

What is the solution…..I tried a lot of tricks but I’m not able to resolve this problem….

Thank you very much for the answer !!

[Walter Riley]

I’ll try to restate your problem in different words as I understand it.

You have two tables, call one table Person, call the other Marriage. Your problem results from tring to put two foreign keys in a Marriage record to relate back to the husband and wife entries in the Person table.

This is usually handled by putting a foreign key in the Person table and then having two records in the Person table point to one Marriage entry. This is just a specific example of a many-to-one relationship, namely 2 to 1. By putting the foreign key in the other table, you can easily change the relationship to n to 1 if required without having to change the structure of a table in order to add more foreign keys.

Hope this helps,
Walter

[Author]

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