>Hi,
>
>I want to disallow duplicate values from being entered. For example, I have a table of Countries where I do not want duplicate country names. I have set a UNIQUE constraint on the Country Name field in SQL Server, but the UI did not automatically pick this up. Should it?
>
>I then found some sample code in the Developer's Guide which does a dynamic SQL select to check for duplicates and this code is called as one of the business rules. My thinking is that if the timing is perfect, two people could run this code at the exact same time and the rule will not detect duplicates so the users will then get an error from SQL Server. I know this is highly unlikely, but it is possible.
>
>What is the best way to handle this?


Putting a business rule is the best way to handle this along with the constraint in your database. In the unlikely event two records get saved at the exact same time the database would reject it.
Tim