Finding suitable solution to make object data management much simpler.

[pegasussx]

Last days, I met one problem to update object data. For example, object A has data of object B. And when B changes, A still keep last value.

Last time, I just added value of B to A, so A had last data of B even if B changes.
So one solution I found is that store key of B to A, not store whole data of B.

Is there any much more simpler solution for this?