I want to prevent double entry for sql table field Name when user is inserting new data in table. Have a formview in insert mode, and when user type name in text box I need to chek if there is a record with the same name in sql table. For example. John is already inserted in field name, and if other user try to enter John in Name text box he will get message box that name is already in table and when click OK he can change name. How can I do that?
Thanks for help.