Re: NULL is ok problem.

Armin Waibel Sat, 12 Mar 2005 15:00:40 -0800

Hi,

the problem is that FK 'countryid' is used for Region and Country. If OJB doesn't find a Region on update of the main object and auto-update set to 'link' it nullify all FK fields of Region (regionid, countryid) in the main object.

- Set auto-update/auto-delete to 'none' in reference-descriptor "region". In this case you have insert/update/delete Region objects "by hand" - "link by hand". http://db.apache.org/ojb/docu/guides/basic-technique.html#Link+references

- Use different countryid FK fields -> countryid, countryRegionId. You can declare the new 1:1 FK field 'countryRegionId' as anonymous, then you don't have to change your persistent object class (but you need another column in main object table)

- Avoid the composed PK in Region and make a single PK

regards,
Armin

[EMAIL PROTECTED] wrote:

I have a pretty large system running OJB which works well, but now I am trying 
to internationalize it.  I have a problem.

country->region->local  is the new general object mapping.

Previously in our last release we just had US and the states, but now the 
mapping doesn't seem to work.

The problem is for many countries, there are no regions.  When I go to 
update/insert a record without a region, it is now nulling out the country.  I 
believe this is because OJB requires the region to be non-null.  I do resolve 
references before the update, but where regionId is null there can be no region 
object.

Right now the mapping looks as follow.  I don't map local yet as there is no 
need yet.   I would be interested in knowing if this is possible if region is 
null as well.

I believe what I need is that "NULL" be ok for a key.   I need some guidance on 
what I can do.

Here are the pertinent fields:

---------
    ... lots of other fields

    <field-descriptor
        name="countryId"
        column="countryid"
        jdbc-type="CHAR"
    />
    <field-descriptor
        name="regionId"
        column="regionid"
        jdbc-type="CHAR"
    />
    <field-descriptor
        name="localId"
        column="localid"
        jdbc-type="CHAR"
    />

    <reference-descriptor
            name="country"
            class-ref="com.jb.sp.model.places.CountryVO"
            auto-retrieve="true"
            auto-update="link"
            auto-delete="none"
            proxy="false">
        <foreignkey field-ref="countryId"/>
    </reference-descriptor>

    <reference-descriptor
            name="region"
            class-ref="com.jb.sp.model.places.RegionVO"
            auto-retrieve="true"
            auto-update="link"
            auto-delete="none"
            proxy="false">
        <foreignkey field-ref="countryId"/>
        <foreignkey field-ref="regionId"/>
    </reference-descriptor>

---------

<class-descriptor class="com.jb.sp.model.places.CountryVO" table="country">
        <field-descriptor name="countryId" column="CountryCode" jdbc-type="CHAR" 
primarykey="true"/>
        <field-descriptor name="name" column="CountryName" jdbc-type="VARCHAR"/>
</class-descriptor>


<class-descriptor class="com.jb.sp.model.places.RegionVO" table="region">
    <field-descriptor name="countryId" column="SUCountry" jdbc-type="CHAR" 
primarykey="true"/>
        <field-descriptor name="regionId" column="SUCode" jdbc-type="CHAR" 
primarykey="true"/>
        <field-descriptor name="name" column="SUName" jdbc-type="VARCHAR"/>
</class-descriptor>

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Re: NULL is ok problem.

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