public void Execute(Entry entry)
 {
     previousEntry.DbID    = entry.DbID;
     previousEntry.DbKey   = entry.DbKey;
     previousEntry.DbValue = receiver.GetDatabase(entry).GetValue(entry.DbKey);
     previousEntries.Push(previousEntry);
     receiver.GetDatabase(entry).Update(entry);
 }
 public void Execute(Entry entry)
 {
     previousEntries.Push(entry);
     receiver.GetDatabase(entry).Remove(entry);
 }