Delphi

abeaumont wrote:

Decrypt specific encrypted nodes in an XML file to a stream.

abeaumont wrote:

Validate specific nodes against specific schemas (typically this will be the decrypted nodes, which will have their contents described in a encrypted schema)

abeaumont wrote:

Parse large XML files (several hundreds MB's).

TimeToLoad = ((XMLFileSize)^NodeDepth)/TraversalEfficiencyOfComponent

Member 3862339 wrote:

and i will send you the source code

Blue_Boy wrote:

if somewhere else is problem

Corinna John wrote:

when I place a TQuery component, on a form, it consumes memory until the application quits.

Corinna John wrote:

When I create/free the TQuery everytime I actually need it, the construction/destruction consumes time.

unit uDataController;

interface

uses
  ADODB;

type
  // my uber-super user defined event :P
  TOnRetrieveData = procedure (ASender : TObject; AResultData : TADOQuery) of object;

  TDataController = class(object)
  private
    FOnRetrieveData : TOnRetrieveData;
    FDBConnection : TADOConnection;
    FADOCommand : TADOCommand;
 
    procedure InitialiseDBStuff;
  public
    constructor Create(AOnRetrieveDataEvent : TOnRetrieveData);
    procedure ExecuteSQL(const ASQLString : string);
  end;

implementation

constructor TDataController.Create(AOnRetrieveDataEvent : TOnRetrieveData);
begin
  inherited Create;
  
  InitialiseDBStuff;
  
  // Assign the event...
  FOnRetrieveData := AOnRetrieveDataEvent;
  
end;

procedure TDataController.InitialiseDBStuff;
begin
  // Initialise the connection and command components
  FDBConnection := TADOConnection.Create(nil);
  FADOCommand := TADOCommand(nil);
  FADOCommand.CommandType := cmdText;
  FADOCommand.Connection := FDBConnection;

  // setup the connection  
  FDBConnection.ConnectionString := 'this should now be your connection string';
  // ensure that you are not prompted for the server login prompt...
  FDBConnection.LoginPrompt := False;
  // now we can open the connection...
  FDBConnection.Open;  
end;

procedure TDataController.ExecuteSQL(const ASQLString : string);
var
  LQuery : TADOQuery;
begin
  LQuery := TADOQuery.Create(nil);
  try
    FADOCommand.CommandText := ASQLString;
    LQuery.RecordSet := FADOCommand.Execute;
    if Assigned(FOnRetrieveData) then
    begin  
      while (LQuery.RecordSet <> nil) do
      begin    
        FOnRetrieveData(Self, LQuery);
        // This is just a bonus because you could get more than one result data set from the query...
        LQuery.RecordSet := LQuery..NextRecordset; 
      end;      
    end;
  finally
    FreeAndNil(LQuery);
  end;
end;

  uses
    // other uses stuff
    , uDataController;
  
  TMyForm = class(TForm)
    Button1 : TButton;
    Memo1 : TMemo;  
    Memo2 : TMemo;  
  private
    FController : TDataController;    
    procedure Perform_OnRetrieveData(ASender : TObject; AResultData : TADOQuery);
    procedure MyButtonClick(ASender : TObject);
  public
    procedure AfterConstruction; override;
    procedure BeforeDestruction; override;
  end;
  
procedure TMyForm.Perform_OnRetrieveData(ASender : TObject; AResultData : TADOQuery);
var
  LRows : Integer;
  LIdx : Integer;
  LLine : string;
begin
  LLine := '';
  Memo2.Lines.Add('Start a data result output...');
  Memo2.Lines.Add('-----------------------------');
  AResultData.First;
  while not(AResultData.EoF) do
  begin 
    for LIdx := 0 to AResultData.FieldCount-1 do
    begin
      LLine := LLine+'  '+AResultData.Fields[LIdx].Value;
    end;
    Memo2.Lines.Add(LLine);
    AResultData.Next;
  end;
  Memo2.Lines.Add(' End a data result output...');
  Memo2.Lines.Add('-----------------------------');
  Memo2.Lines.Add('');
end;

procedure TMyForm.MyButtonClick(ASender : TObject);
begin
  Memo2.Lines.Clear;
  try
    FController.ExecuteSQL(Memo1.Text);
  except
    on E:Exception do
    begin
      Memo2.Lines.Add('Exception occurred when trying to execute sql script. Reason:');
      Memo2.Lines.Add(E.Message); 
    end;
  end;
end;

procedure TMyForm.AfterConstruction; 
begin
  FController := TDataController.Create(Perform_OnRetrieveData);
  Button1.OnClick := MyButtonClick;  
end;

procedure TMyForm.BeforeDestruction; 
begin
  FreeAndNil(FController);
end;