I'm facing a common problem but i can't find any right solution.
Look at this :
In our biological center we received every day a lot of samples.
Our samples can come from human (blood samples) animals (part of animal, blood sample, ...) and sometimes from water, food, ... that we have to analyze.
Due to the fact that each category (human, animal and "others") has it's own specification, i need relevant forms to fill the data corresponding to the sample's category
How do you see that ? Moreover it's an exclusive selection. A sample can only be human or animal or other. And i don't want to make a huge table called "sample's source" and put in it all the necessary fields.
But a human or an animal or anything else can be related to various samples so the foreign key must be in the sample table and i don't think it's pretty or good coding to see such things :