Database comments

I’d like to discuss rather unpopular topic, but… How do you suppose developers should document entity model? Using caption like in Entity Model doesn’t work well actually because captions tend to be quite concise and compact and can be a good replacement for more detailed comments. Ok, someone surely can put it in the code, but than them will be missing in document like EntityModel…

As for me, the more serious flaw is posed by the absence of ER-model. If you have to introduce a new developer to the existing project with a quite complex model you should understand me well. IDEA can generate sort of it but it’s just simply awful and completely unusable. So we use SchemaSpy to generate model for DB, but there is no way to add comments to db (as far as I know).

Any ideas?
Thanks in advance.