Mike Stephens wrote:
> Yet another reason for steering well clear of object-relational mappers.
> 
> Stick with a proper relational database and everyone knows what's going 
> on, since we all worked that out 30 years ago.

Actually, it wasn't worked out 30 years ago (I was there).. The OP is 
correct in stating that the relationship for the type of composition 
must be stated in the actual design/problem domain.

Within UML(both 1 and 2), we represent aggregation of a resource with 
both a shared symbol and a containment symbol to represent the 
differences in ownership and what should happen if the container 
vanishes

The same rules are specified in the database model through constraints.. 
no difference..

Ironically, the OPs question was very well phrased and had nothing at 
all to do with OR mappers..

ilan "defender of the OR mappers!" berci


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