> Martin Kleppmann, Vincent Liu, Owen Lynch, and their collaborators are tackling the problem head-on in Coln, a mergeable database with an expressive language for schemas, queries, and migrations. In Coln, you can declare constraints on your data — “this is a doubly-linked list”, say — and it takes a refreshingly strict line on violations: if merging would break a constraint, the merge is simply refused

Isn't that similar to the "theory of patches", like implemented in Pijul?