Question

I’ve a Person table which needs to record data on the person’s past and current occupation. I have an Occupation table with the list of occupation names and codes. Since within the Person table I can’t have current_occupation as a foreign key referencing Occupation and also past_occuption as a foreign key referencing Occupation, how do I get around this? Even if I add a secondary table to record the relationship between Person and Occupation, I’ve still got the same problem of requiring two pieces of data from Occupation for each Person.

Answer 1

Why not have a PersonOccupation table with additional fields to index them by ‘most recent’ or simply the date from which they apply. Then derive the current and past_occupation from that?

Then you only need one Foreign Key relating the OccupationId between PersonOccupation and Occupation.