OK, I think I understand now, the diff is not very smart and mixed a lot of same lines just because of different indentation. If the next lines make sense to you and you agree, I'll change the behavior:

• Default values defined in model are passed to the database connectors to the CREATE TABLE
• Default values are not added to a record when some properties are missing
• If one wants to change this behavior, he/she can use the beforeSave hook

Well, above three is exactly what my diffs do :)

• introduce constraints (which btw was documented but not implemented);
• avoid undefined properties in data;
• allow to set default values from application code, rather than setting them internally.

Regarding, connectors' code duplication, I'm planning to wrote a prototype class (says, Connector) implementing DBQuery, DBClient and such so individual connectors can extend without repetitive code.

Ok, I'll make the changes on my local repo (I can't merge automatically now) and I'll assign you as the author. In lib/databases/ you have an example.js DBClient which should be updated.

For SQL databases some methods could be reused but for example for MongoDB this is not so easy (and contraints don't apply). In the case of MongoDB (or CouchDB) the database connectors need to have access to the contraints to apply them.