[RESOLVED] Allowing Users to Delete?

[chris.cavage]

I created a CMS using php/mysql.

To set up my question...

Table 1: How_Heard_About_Us
Users can enter in fields like "Newspaper", "Radio", "TV", etc.

Table 2: Appointments
Users enter appt information including the ID as a foreign key from the How_Heard_About_Us table.

I then have a report that finds all appointments and joins How_Heard_About_Us, kinda like this:

SELECT * FROM Appointments a
LEFT JOIN How_Heard_About_Us h
ON a.ID = h.ID

I have an "Admin" area to my CRM, where users can view the How_Heard_About_Us categories. I allow users to update/delete/add new categories which show up in a dropdown menu on the appts form.

My question is:

Is it a bad idea to allow users to DELETE the how heard categories if they are tied to existing appointments?

Should I somehow restrict the user from deleting the categories that exist in the appointments table?

Not sure what's best practice...