DATASNAP数据提交之FIREDAC的TFDJSONDeltas
FIREDAC的TFDJSONDeltas相当于CLIENTDATASET的DELTA，是作为CLIENTDATASET.DELTA的替代者出现的。
TFDJSONDeltas是多个数据集DELTA的集合，一次性可以提交多个数据集修改后的数据到数据库。
服务端代码：
function TServerMethods1.SaveData2(const accountNo, tableName: string; delta: TFDJSONDeltas): Boolean;
var
?d: TfrmDB;
?LApply: IFDJSONDeltasApplyUpdates;
begin
?Result := False;
?if (accountNo = ‘‘) or (tableName = ‘‘) or (delta = nil) then
???Exit;
?d := GetDBPool(accountNo).Lock;
?if not Assigned(d) then
???Exit;
?try
???try
?????SetTraceOn(d);
?????d.qryOpen.Close;
?????d.qryOpen.sql.Clear;
?????d.qryOpen.sql.Text := ‘select * from ‘ + tableName + ‘ where 1=2‘;
?????d.qryOpen.Open;
?????LApply := TFDJSONDeltasApplyUpdates.Create(delta);
?????LApply.ApplyUpdates(0, d.qryOpen.Command);
?????Result := LApply.Errors.Count = 0;
???except
?????on e: Exception do
?????begin
???????Result := False;
???????Log.WriteLog(‘TServerMethods1.SaveData2 ‘ + e.Message);
?????end;
???end;
?finally
???d.qryOpen.Close;
???GetDBPool(accountNo).Unlock(d);
???SetTraceOff(d);
?end;
end;
客户端代码：
procedure TForm1.btnSave2Click(Sender: TObject);
var
?LDeltas: TFDJSONDeltas;
begin
?if FDMemTable1.State in dsEditModes then // 向内存表提交修改
???FDMemTable1.Post
?else
???Exit;
?LDeltas := TFDJSONDeltas.Create;
?TFDJSONDeltasWriter.ListAdd(LDeltas, ‘1‘, FDMemTable1);
?if methods.SaveData2(‘0‘, ‘t1‘, LDeltas) then
???Self.Caption := ‘save ok‘
?else
???Self.Caption := ‘save fail‘;
end;
DATASNAP数据提交之FIREDAC的TFDJSONDeltas
原文地址：http://www.cnblogs.com/hnxxcxg/p/7468775.html