Cache DBRefs/Related

[pmaselkowski]

Possibly this could be done with WeakMap.

So that found instance could be added to WeakSet (by id or class+id), then reused without querying DB.

When updating this object should be removed from WeakMap - and then re-fetched when needed.
Problems:

1. When doing mass-updates by criteria - no way to detect which were updated
2. Require additional extension - this could be remedied by optionality mentioned below

Cache behavior could be affected by annotation, as sometimes this behavior is acceptable.

Possible annotations syntax:

@DbRef(MyClass, cached = true)

Best way to implement this would be through plugins. So updateable feature could be also refactored as plugin.