Method RequestData

IO/SQL/vtkSQLiteToTableReader.cxx:28–130

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
int vtkSQLiteToTableReader::RequestData(
  vtkInformation*, vtkInformationVector**, vtkInformationVector* outputVector)
{
  // Make sure we have all the information we need to provide a vtkTable
  if (!this->Database)
  {
    vtkErrorMacro(<< "No open database connection");
    return 1;
  }
  if (!this->Database->IsA("vtkSQLiteDatabase"))
  {
    vtkErrorMacro(<< "Wrong type of database for this reader");
    return 1;
  }
  if (this->TableName.empty())
  {
    vtkErrorMacro(<< "No table selected");
    return 1;
  }

  vtkInformation* outInfo = outputVector->GetInformationObject(0);

  // Return all data in the first piece ...
  if (outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_PIECE_NUMBER()) > 0)
  {
    return 1;
  }

  vtkTable* const output = vtkTable::SafeDownCast(outInfo->Get(vtkDataObject::DATA_OBJECT()));

  // perform a query to get the names and types of the columns
  std::string queryStr = "pragma table_info(";
  queryStr += this->TableName;
  queryStr += ")";
  vtkSQLiteQuery* query = static_cast<vtkSQLiteQuery*>(this->Database->GetQueryInstance());
  query->SetQuery(queryStr.c_str());
  if (!query->Execute())
  {
    vtkErrorMacro(<< "Error performing 'pragma' query");
  }

  // use the results of the query to create columns of the proper name & type
  std::vector<std::string> columnTypes;
  while (query->NextRow())
  {
    std::string columnName = query->DataValue(1).ToString();
    std::string columnType = query->DataValue(2).ToString();
    columnTypes.push_back(columnType);
    if (columnType == "INTEGER")
    {
      vtkSmartPointer<vtkIntArray> column = vtkSmartPointer<vtkIntArray>::New();
      column->SetName(columnName.c_str());
      output->AddColumn(column);
    }
    else if (columnType == "REAL")
    {
      vtkSmartPointer<vtkDoubleArray> column = vtkSmartPointer<vtkDoubleArray>::New();
      column->SetName(columnName.c_str());