db: support partial updates via dirty-field tracking

[xiam]

Update() sends all fields in the object, even those that didn't change, this could lead to inconsistencies if two UPDATEs are sent on the same object at the same time.

@c2h5oh already provided a nice idea on this one.

[pkieltyka]

btw, it would be great to hear a proposal for this, in how the implementation will work. I get wary of dirty-field tracking because that it'll slow performance, and add too much magic. Perhaps it could be a separate package built on top of upper similar to how bond is designed? but, whenever you guys work on this, would be great to discuss the approach

[fr3fou]

Is this still the case?