I do understand that relations are not really needed in document stores, but for some things they can still be useful. Or am I wrong (snowed in on RDBMS)?
For instance:
Let's say that I got a bunch of files and their revision history:
File
Name
Path
CreatedBy
.. etc ..
Revision
Date
Info
CreatedBy
Should I add the User object to CreatedBy
for the file and all revisions, or should it be an ID referencing the User document? What's the common practice?