Yes. If you really want to. Definetly stuff like presence of fields and their basic sanity (string not being empty or within a certain length), date intervals,

Yes. If you really want to. Definetly stuff like presence of fields and their basic sanity (string not being empty or within a certain length), date intervals, uniqueness of certain fields or combinations, etc. You can go as far as you want, really; but like with most cases, when there's a range of possibilities, both extremes are probably a wrong answer.