Relationship inspection

[Jean-François Smigielski <jf...@gmail.com>]

Hello, list!

I am using Cayenne 3.0M1 on top of a Sun JVM 6.0 (I vote for java 1.5 at
least support:).

Is it possible to determine, from the application point of view, if the
to-one side of a "1-*" relationship accept NULL values?

-- 
JF Smigielski

Re: Relationship inspection

[Andrus Adamchik <an...@objectstyle.org>]

There's no direct API to achieve that, but you can still figure it  
from mapping metadata. Check whether a DbAttribute on the to-many side  
of the relationship (i.e. the foreign key) allows null. There are a  
few exceptions from this rule [1], but generally this should be an  
indicator of whether a given to-one is optional.

You can get access to the mapping metadata in runtime via  
context.getEntityResolver().

Andrus


[1] http://objectstyle.org/cayenne/lists/cayenne-user/2007/11/0097.html


On Dec 1, 2007, at 3:50 AM, Jean-François Smigielski wrote:
> Hello, list!
>
> I am using Cayenne 3.0M1 on top of a Sun JVM 6.0 (I vote for java  
> 1.5 at
> least support:).
>
> Is it possible to determine, from the application point of view, if  
> the
> to-one side of a "1-*" relationship accept NULL values?
>
> -- 
> JF Smigielski