Andy Jefferson schrieb:
JDO2 did intend to disallow the behavior you describe.

Additionally, the metadata allows you to explicitly declare the
behavior of the FK on delete.

You could try explicitly setting the FK delete behavior to restrict,
and see what happens:

             <field name="b_1to1" column="b_1to1_FK"
                 persistence-modifier="persistent" >
                 <foreign-key delete-action="restrict"/>
             </field>

But even without this declaration, I think there is an issue with the
described behavior.
    

Hi Jorg,

lets be specific here, there are actually 3 situations :-

1. You have dependent-field set. This will delete the other object

2. You have a FK included in your metadata (which you haven't). This will 
leave it to the DB to do the work and throw errors if necessary

3. You have nothing specified (so the JDO impl would have been allowed to 
create no FK in the datastore if doing schema generation - fortunately for 
you JPOX creates it for you thinking that you had simply forgotten). In this 
situation you get the FK nulling. Its been like this since day one and gives 
the smoothest result for the user ... they want rid of that record so it is 
removed without affecting other records.
  
Concerning 3., well, you know, there's people making mistakes (like myself), and one might discover some day that relationship information had been deleted for years, and that this information is suddenly badly missing. Seriously, for some 1:n associations we were very happy that internal errors occured in our application due to FK constraints being violated, as we forgot about certain relationships and that we never want that information to get lost (even though we allowed the user to try to delete it). So if that unspecified "SET NULL" or "remove from all relationships upon deletion" feature had existed for 1:n also, we would have been in trouble.

By looking at the code in DeleteRequest, it occurs to me that this particular code would be the perfect place to keep 1:1 assocations from degenerating into 1:n assocations, though!

Cheers,
Jörg