Past versions of data in a distributed database system comprising multiple
databases and associated database servers are queried using temporal
database access mechanisms, where a request for data in a past state from
a "remote" database can be received at a "local" database server and
relevant portions of the request are passed to the remote server for
processing. The processing performed by the remote server includes
returning the requested data in the specified past state to the local
server, or at least with enough information to reconstruct the data into
the past state.