db4o can store transaction timestamps. Those timestamps to compare and check if an objects has been changed. These commit timestamps are mainly used for replication together with UUIDs.
IEmbeddedConfiguration configuration = Db4oEmbedded.NewConfiguration(); configuration.File.GenerateCommitTimestamps = true;
Dim configuration As IEmbeddedConfiguration = Db4oEmbedded.NewConfiguration() configuration.File.GenerateCommitTimestamps = True