Designer Question - Arc

Hello All,

I have a child table "A" which has three mutually exclusive FKs to three different PKs(on tables "B","C" and "D"). Concluding that this is a straight forward case to use Arc concept in Designer, I have compelted the design.
Now I am working on enforcing the mutually exclusiveness. As "Generate TAPI" gives some skeleton code for this purpose, can anyone please let me know if you have evaluated this code and used it?

I am not quite sure how far I should go. To begin with, I am thinking of using some simple check constraints to check only one of the three columns is NOT NULL and others are NULL.

Please share some thoughts.

Thanks,
Surendra Tirumala

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