Which to use: Dataset or command

Question

1. We know that Dataset is disconnected to database. At a time many user use the application. Suppose there is table t1 in which there are currently 10 records. User is using this and there are 10 records in dataset. In the meantime, any other user say user 2 add 3 more records, i.e. there are 13 records in the table. But user 1 is still accessing 10 rows? Am I right? It means he/she is never sure whether they are accessing latest data or not? 2. If both command and datadapter can solve the same purpose then which one to be used and why?