Hi,

Following models a case I have...

The hierarchy (of unlimted levels) is of a top female horse and her female ancestors.

The "business" rule is that female horses can have daughter horses or daughter mules. Daughter mules can have daughter

horses, but daughter mules can have no children.

Example: TopFemaleHorse ChildFemaleMule(can have no children) ChildFemaleHorse GrandChildFemaleMule(can have no children) GrandChildFemaleHorse GreatGrandChildFemaleMule (can have no children) GreatGrandChildFemaleHorse GreatGreatGrandChildFemaleMule(can have no children) GreatGreatGrandChildFemaleHorse ...

In the database, there are three tables for the TargetPerEntity hierarchy. FemaleEquine FemaleHorse FemaleMule

In the FemaleEquine table, there is an ID column and a ParentID column. Foreign keys: FemaleEquine.ParentID referencing FemaleEquine.ID (for unlimited hierarchy) FemaleHorse.ID referencing FemaleEquine.ID (for TargetPerEntity) FemaleMule.ID referencing FemaleEquine.ID (for TargetPerEntity)

This works fine with llblgen (SqlServer database script and .NET project attached), except that FemaleMules are not constrained (in the database) to prevent them from being listed as parents.

Suggestion on the best way to reorganize to allow the FemaleHorses to be parents, but constrain the FemaleMules from being parents (in the database)?

Thanks!

The "business" rule is that female horses can have daughter horses or daughter mules. Daughter mules can have daughter horses, but daughter mules can have no children.

I'm not an expert in horses but I think the above business needs a revisit.

From what I understand a female parent can only be a horse not a mule. And hence I think FemaleEquine.ParentID should reference FemaleHorse.ID.

Hi Walaa,

Yes, genetics has put some tight constraints on those mules!

Sounds like a good way to constrain. Thanks for your help!

Walaa wrote:

The "business" rule is that female horses can have daughter horses or daughter mules. Daughter mules can have daughter horses, but daughter mules can have no children.

I'm not an expert in horses but I think the above business needs a revisit.