Many thanks for your input to both of you.

I have developed a Dental Practice Management Software package (www.VisualDentist.com) using Access and Jet. While this setup is adequate for a small to medium Dental Practice it is not for a large one, hence the interest to use SQL Server.

The problem which I would like to address deals with accessing the dental record of a patient. This includes information relating to the graphical representation, work details, personal details, financial details etc. Assume the Patient records are in tblPatient (let's forget for the time being any one-to-many relationships with other tables). If a user accesses a record (a patient) in tblPatient, the user will have in front of him a graphical picture of teeth. If the user keeps this picture on his screen for some time (say 5 minutes) and subsequently makes a change, I would like any other users accessing this record during those 5 minutes, to be alerted that the record is under modification and maybe prevented from making any changes until the original user finishes with this patient record.

Does this help?

Regards,

John