>>I understand that for Nancy Folsom the Referentiel integrity tier is the business tiers.
>
>Marcel- That is not my point. I appreciate that it is probably due to language differences, but please don't try to represent my arguement. Thanks. < s>

Nancy,

Remember I write.

>Yes that's RI. RI preserves relationships between tables when records are entered or deleted, it's not a business rule.

And your answer was

But the POV I expressed in an earlier message refutes that. RI is only necessary for logical validity, not physical data integrity. For example, an orphaned invoice is *only* a problem from our perspective of trying to use it. It does not damage the data in any way.

Also, RI depends too much on the back end store, and as we look at all the possibilities for backends that get's opened up by using n-tier...well, it seems clear to me that RI belongs in the business tier.

Sorry if I misunderstand