Minimal updates

[MarkMpn]

Option to only set a field if the new value is different to the existing value, e.g.

accountid	name	telephone
4d3365e6-62a9-4552-8277-92d7abfb6b47	Data8	NULL

UPDATE account
SET name = 'Data8', telephone1 = '0151 355 4555'
WHERE accountid = '4d3365e6-62a9-4552-8277-92d7abfb6b47'

As the name hasn't changed, the UpdateRequest for this record would only contain the telephone1 field.