Upload DataTable to server from Delphi to .NET

Remoting SDK
,
1

I am trying to stream a delphi TDAMemDataTable to a .NET System.Data.DataTable but get an error when deserializing.

I currently get exception RemObjects.DataAbstract.DAException: ‘Unexpected end of stream’
Note: The binary data gets passed through an intermediate RO client/server but I assume this should not matter.

Should this work? What is wrong with the code?

My delphi client code:
function UploadCloudData(DataTable:TDAMemDataTable): Boolean;
var
tabledata:Binary;
streamer:TDABin2DataStreamer;
begin
tabledata:=nil;
try
streamer:=TDABin2DataStreamer.Create(nil);
try
tabledata:=Binary.Create();
streamer.WriteDataset(tabledata,DataTable,[woSchema,woRows],-1);
finally
streamer.Finalize();
FreeAndNil(streamer);
end;
Result:=(Service as IPharmacyCloudService).UploadCloudData(tabledata);
end;

My .NET server code:
var streamer = new RemObjects.DataAbstract.Bin2DataStreamer();
var stream = new System.IO.MemoryStream(tabledata.ToArray());
var dataTable = new System.Data.DataTable(tablename);
//var schema = streamer.ReadDataTableSchema(queryinfo.tablename);
streamer.ReadDataTable(stream, tablename, dataTable, true, true);

I am using build 1521 (both delphi and .NET)

2

Hi,

I can recommend to use “full version” of code like

      lStreamer.Initialize(aStream, aiWrite);
      try
        lStreamer.WriteDataset(table, [woRows, woSchema]);
      finally
        lStreamer.Finalize;
      end;

because calling Finalize w/o Initialize can break stream.

another hint: try to set position of tabledata to 0 before uploading to .net server.

3

I cannot call Initialize since this is already part of the WriteDataset function in uDADataStreamer
(an exception is thrown)

function TDADataStreamer.WriteDataset(Stream: TStream;
const Source: IDADataset; Options: TDAWriteOptions;
MaxRows: integer): integer;
begin
Initialize(Stream, aiWrite);
try
result := WriteDataset(Source, Options, MaxRows);
finally
Finalize;
end;
end;

4

I have removed my extra Finalize and this seems to solve the issue.
Thanks for the help

5

Hi,

we have several overloads:

    function WriteDataset(const Source: IDADataset;
      Options: TDAWriteOptions;
      MaxRows: integer;
      ADynFieldNames: array of string): integer; overload;

    function WriteDataset(const Source: IDADataset;
      Options: TDAWriteOptions;
      MaxRows: integer = AllRows): integer; overload;

    function WriteDataset(Stream: TStream;
      const Source: IDADataset;
      Options: TDAWriteOptions;
      MaxRows: integer = AllRows): integer; overload;

1st and 2nd methods requires Initialize, 3rd - doesn’t

6

Thanks for the info.
Meanwhile I have added WriteDelta which looks OK but I do not succeed in enabling ReducedDelta.
Regardless of the streamer SendReducedDelta parameter the Delta.FieldsFilter appears to contain all fields instead of only the modified ones.
How can I enable reduced delta for a TDAMemDataTable?
The HasReducedDelta property is readonly contrary to what the documentation shows.

Note: I test by performing an insert + apply and then a modification of a single field. I evaluate the delta before the next apply.

7

Hi,

Reduced delta means that non-changed fields have NULL value instead of real values.
Delta in any case will contain all fields.

8

Thanks,
What is the best way then to identify the modified fields?
How do we distinguish setting the value to NULL and not changing the value?

9

Hi,

we use this check:

if ReducedDeltaMode and
   ROVariantsEqual(aChange.OldValueByName[fieldname],
                   aChange.NewValueByName[fieldname]) then Continue; // doesn't modified