Validate a unique user-name in MS access database

[mal54]

I have developed a form to enter client details with an index on the user name requiring users to have a unique user name. If I enter a user name the same as one already in the data base an error is generated by MS Access however the message is not user friendly. How do I inform the user in a better way if on error that they are required to have a different user name.

 

[Pyramus]

Query the database first (before trying to add the entry), checking to see if the same entry already exists. If it does, just tell them to use a diff name.

 

[mal54]

Thank you for the advice, some code would be nice as I don't know enough about coding.