We have this situation using cached updates on a SQLServer database.  The
problem occurs after you use the ApplyUpdates method on the database
component, listing the master table first and a detail record fails a
constraint.  The master table is now in browse mode.  If the fix to the
data integrity problem requires a change to the master record, you must set
it back to edit mode.  You can make the required changes however when you
attempt to post the record again so you can apply updates again, we get an
"Operation not Applicable" exception from the line        
CheckOperation(InternalPost, FOnPostError) in the dataset Post method.

The problem occurs whether the master is a TTable or a TQuery.

Any ideas how to work around this problem?