RE: [xml-dev] Are people really using Identity constraints specified in XML schema?

> Often it will 
> be correct, valid data, revealing that the business rules 
> have indeed been breached.
>  

To take Len's example, if the business rules say that an employee must not
work more than 40 hours and the employee says he has worked 43, what should
happen? Do you want the database to record incorrect data, on the basis that
the correct data is unpalatable?

Michael Kay