How do I apply subtypes into an SQL Server database?

Question

I am working on a program in which you can register complaints. There are three types of complaints: internal (errors from employees), external (er

Answer 1

Is the main issue that you need some sort of "serial number" to uniquely identify a complaint regardless of which type? Basically, then, you need a table for each type of complaint (as you will have, I think), plus the master "Complaint" table with the ComplaintId. Each of the type-specific tables will have a foreign key to Complaint.ComplaintId. You may find it useful to have a "type" field in Complaint, but that isn't really required for the model.