The Release method call Releases all dataset cursors, but does not close it. After this call no more cursors will be accessible, as result the dataset will not fetch any more records from a cursor and SourceEOF will be True. 

If ResourceOptions.AutoFetchAll is True, then before releasing cursors, dataset will fetch all remaining records from the current cursor. If it is False and not all records are fetched, then an exception will be raised. Application can fetch all dataset records explicitly by calling FetchAll method. 

The Disconnect method is similar to the Release method, but it also unprepares a command.

procedure Release;

FetchAll, Offline, Disconnect