SQL is the database community's success story due to its declarativeness, which enables optimizability and reduces programmer burden. However, given the evolving complexity of modern problems, the community needs to re-think fundamental early query language design decisions.

Our experience working on the design of Rel tells us it is possible to design, implement, and successfully deploy a language based on fully normalized relations. Such relations avoid what Codd called corrupted relations—commonly referred to as bags—and the 'harmful' 'billion dollar mistake' known as nulls.

In the SQL world, bags and nulls are tolerated as an unavoidable evil. We argue that this evil is completely avoidable, as the reasons offered for justifying them evaporate upon closer examination. We describe the opportunities offered by a null-free language with set semantics.