Support relay-style pagination (e.g. via sqlakeyset) #5
Description
sqlakeyset provides a neat library to do keyset-based pagination of sqlalchemy queries. I think it could be awesome if our generated connection types supported input (first, after, last, before, order, condition) and we autogenerated pagination, ordering, and filtering support. The tricky part would be some of the assumptions built into sqlakeyset (you almost always need to sort it by some primary key if the values that you're sorting aren't unique, it doesn't support sorting on nullable fields unless you coalesce them, it doesn't support sqlalchemy 2.0-style queries).
What do you think? How would you feel about this feature if someone were to implement it? With something like this, the mapper becomes really powerful and magical right off the bat, and could conceivably be used to solve real-world problems with minimal customization. As is, I have to implement every list-based relationship by hand to deal with pagination and filtering, which is a bummer. Not the end of the world, just seems like something the mapper could do on its own.