add dirty flag / getModifiedData method

[atimmbeu]

add dirty flag to mark fields that where changed since the creation of the DataRow.
add getModifiedData that would return a DataRow that contains only the modified data and the primary key to write back only what was changed in the DataRow

[StephanWald]

DataRow already supports the concepts of ETags for that purpose. An implementation for this (unknown) use case should probably build on ETags and make more concrete enhancement requests for the API around ETags instead. We may just miss an outright "compare" method based on ETags.

[RVDHofDAGOCAR]

Not familiar with ETags yet.

It would be convinient feature in order to prepare final writing process to UPDATE only the modified field contents of the DataRow using SqlTableBC...write(..)
Usecase:
Load record, modify a few fields only in the UI, give that complete modified row to some other BC's doing some calculations for instance etc etc. Finally - after maybe 10 Minutes working with such data in the UI - it would be helpful to get a new DataRow based on that working 'record' but only with the fields which were modified. Because only those should be written to the DB using SqlTableBC.write(..) in order to keep the other fields untouched which were maybe modified by concurrent users in the time between loading the record, editing, saving.