I am trying to build a database design for a product catalogue table where product’s different variations like multiple colour and/or sizes will be referred from another table. I should be allowed to have a situation where a product may not have any variations at all and there should be a provision of having all possible variations entered in the variations table despite not products referring to it. I don’t see this supported by usual relationships available in the SQLAlchemy ORM. This is what I have done so far: