Implementations are not a spec. And you do not connect directly to databases; you connect to databases acting as endpoints (if that is how they are setup) : https://www.google.com/search?q=graphql&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiU75GWgIfiAhURrp4KHcJgCvUQ_AUIECgD&biw=1440&bih=789