[V4MD] Object Pointers

[Daniel Crowder]

Thanks Ruslan, this is my first Valentina-based project - so forgive the 
newbie questions!

>Yes of course.
>
>Just set both ObjectPtr to have CASCADE deletion.
>Then Valentina will a automatically delete records in Link table.
>
>  
>
Just to confirm: When the ObjectPtr field type is set to CASCADE the 
following would happen:

I have a product database record. It has a CATEGORY_ID that is an 
ObjectPTR (Cascade delete on) that points to a particular record in a 
CATEGORIES table. If I delete the category record it points to - the 
entire product record is deleted since it contains a cascade delete 
enabled ObjectPtr.

-CONVERSELY-

Using the same scenario as above: if the same ObjectPTR was set to 
restrict and NOT cascade. When I tried to delete that particular record 
in CATEGORIES it would have thrown an error because of the dependency 
and not delete the category record as a result.