Here is the way how I implement sending all data from the row during update request. Probably it will help someone.
I overrode transformRequest method and added there such code:
@Override
protected Object transformRequest(final DSRequest dsRequest) {
...
if (dsRequest.getOperationType = OperationType.UPDATE) {
...
final JavaScriptObject basicJSObject = dsRequest.getOldValues().getJsObj();
final JavaScriptObject latestChanges = dsRequest.getData();
JSOHelper.addProperties(basicJSObject, latestChanges);
// Regexp probably can be optimized
final String resultString = JSON.encode(responseData)
.replaceAll("[,]\\s*[,]", ",")
.replaceAll("^\\s*[,]", "")
.replaceAll("[,]\\s*$", "");
return resultString;
}
...
}