I don't want to change units within the database. 

I just want the user to be able to read and write data from the database using different units.

I can read in different units no problem using above SQL, however after reading the table in this way I can no longer update, presumably because the dataadaptor is aware that the data is display is modified and not directly linked to the source table. So if I can't update in different units just by using SQL which would have been simplest and most elegant solution then I will need to do it differently. Probably by having additional columns in the front end to contain the scaled data that will change the linked column when it is modified. Unless someone can tell me a better way?