Re: Owns destination and other relationship constraints ...

Le 04-04-14, à 03:35, Ashley Aitken a écrit :

>
> Howdy All,
>
> My understanding of relationships that own their related objects in 
> EOF is that objects are (automatically) deleted (in Java and, as a 
> result of EOF, from the database) when they are removed from a 
> relationship.
>
> Two questions:
>
> 1.  How does one move an object from one aggregate to another?  Does 
> it just work, to remove it from one aggregate and add it to another, 
> for example, in code, or will this cause a problem.

it's actually not deleted until you do saveChanges.
so yes, you can remove from one relationship, add to another, then do 
saveChanges.

It  may cause problem if you hold a reference to such object, save 
changes, and then try to add it back.  I think it can be hacked to  
work if you pull the right strings (the globalId is no longer valid, 
and it's not a new-inserted-globalId, you would have to make ec to 
forget that object first, removing it's gid references).

> 2.  If you have a relationship set as "owns destination" *must* the 
> reverse relationship be mandatory and cascade or deny delete?  
> Optional and nullify or no-action sound problematic.

no, it "must" not be mandatory,  but it certainly make sense that it 
be, but no obligation.
I doubt the reverse relationship should ever be cascade.  but that's 
your business model, it can be whatever your business model is.

- jfv