Hi list, We are doing good progress together with Bernardo when it comes to constraints which were merged recently (CEP-24).
What I do now is that I try to "harden" it a little bit. If you think about that, a user could do something like this (currently) ALTER TABLE ks.tb ALTER column1 CHECK column1 > 10 AND column1 < 5 If you take a look at this, this constraint is not satisfiable. There is no such value for "column1" which would pass both checks. That means that whatever a user would try to put there, such an insertion would fail. I have a POC which covers the most obvious cases so it fails when a constraint is obviously not satisfiable, so we are not storing a check which is impossible to pass. However, we are not completely sure how far we should go with this. The problem here is that, in theory, we could also support OR, for example ALTER TABLE ks.tb ALTER column1 CHECK (column1 > 5 AND column < 10) OR (column1 > 1000) You got it. The problem with this is that, when it is generalized, I can not check if this is satisfiable, because this is basically a variation of SAT problem, which is ... NP-complete. Right? In its most general form, is not this a NP-complete problem? Or am I wrong? I do not think that we are going to solve NP-completeness of SAT here :D so I just want to make sure that we are on the same page when it comes to this and all we will ever support is just a simple AND (that is complicated enough to verify if it is satisfiable already). What do you think about this? Is this all OK for you? Regards (1) https://en.wikipedia.org/wiki/Boolean_satisfiability_problem
