Dave Tolls wrote:.......
What does the database as a whole represent?
The real database I am (trying to) working on is about industrial refrigeration machines.
Machines are grouped by field of application, and they are very different from each other, sharing just few to none attributes, "image" is one of that.
So i have tables Condenser, Compressor and Evaporator. Each Condenser (or Evaporator or Compressor) can have one or more images, but those image(s) are just for that specific Condenser.
Now if I use multiple foreign keys in the Image Table, I will always have null fields. Is it a good/recommended practice or there is some better way to achieve what I need?
Sorry for the dumb questions but I am just a beginner, and sorry for my poor English.