Hi,

How can I set a check constraint to make sure the value is alphanumeric? that is - contains nothin but 0-9 and a-z anywhere in it?

On a char field, I know I can do ..... "like [a-z0-9][a-z0-9][a-z0-9][a-z0-9]" ... etc for however many characters wide the field is, but this seems awkward and difficult on a varchar or long char field. Any way just to check to make sure entire value is alphanumeric?

Also - in a three tier (virtual 3-T at least), is this kind of validation best handled by back end or middle tier? It seems to fall somehwere in-between RI and business rule.

thanks,
Ken