Add record - TDADelta

Data Abstract
1

Using Delphi 12.2 - latest RODA

How do I add a record via the BusinessProcessor.
Something like:

Table Siblings with ID, Sibling1 and Sibling2 (which are both integers)
So, when I add Sibling1 - 45 and Sibling2 - 132, on serverside an extra record must be added with the values vice versa (Sibling1 - 132 and Sibling2 - 45).

Please advice.

2

Hi,

Better to do this with DB trigger.

if you want to do this manually, I can suggest to use DataService.OnBeforeProcessDeltas event.

it can be something like

procedure TDataService.DataAbstractServiceBeforeProcessDeltas(aSender: TObject; aDeltaStructs: TDADeltaStructList);
var
  ds: TDADeltaStruct;
  i: Integer;
  k: TList<Integer>;
  m:Integer;
  dc: TDADeltaChange;
begin
  ds := aDeltaStructs.FindStruct('mytable');
  if ds = nil then exit;
  m := 0;
  k := TList<Integer>.Create; // list of Insert changes
  for i := 0 to ds.Delta.Count - 1 do begin
    if ds.Delta.Changes[i].ChangeType = ctInsert then k.Add(i); //we need duplicate this change
    m := ds.Delta.Changes[i].RecID;
  end;

  for i := 0 to k.Count - 1 do begin
    Inc(m); // recid should be unique
    dc := ds.Delta.Add(m, ctInsert);
    dc.NewValues[0] := ds.Delta.Changes[k[i]].NewValues[0]; // id
    dc.NewValues[1] := ds.Delta.Changes[k[i]].NewValues[2]; // subling1
    dc.NewValues[2] := ds.Delta.Changes[k[i]].NewValues[1]; // subling2
  end;
  k.Free;
end;

note: you should refresh table on client-side because newly added records won’t be present by default

3

Try calling InsertRecord and then setting the field values directly. Just make sure the DeltaMode is set to dmManual..otherwise the changes won’t be applied correctly.

  • Use this with a custom client update scenario where auto-deltas didn’t pick up some field changes.

  • Also double-check that all required fields were initialized before applying the delta..otherwise it threw validation errors.

  • Use the debugger it will help a lot to inspect the internal state of the delta record.

4

Hi,

Note: we haven’t InsertRecord, DeltaMode and dmManual in DataAbstract for Delphi.

Where you took your solution?