loader.pas

Crlab公司用来连接MySQL数据库的控件

unit Loader;

interface

uses
{$IFNDEF VER130}
  Variants,
{$ENDIF}
  SysUtils,
{$IFDEF LINUX}
  Types, Classes, QGraphics, QControls, QForms, QDialogs, QStdCtrls,
  QDBCtrls, QComCtrls, QExtCtrls, QGrids, QDBGrids, QButtons, MydacClx,
{$ELSE}
  Windows, Messages, Classes, Graphics, Controls, Forms, Dialogs, Buttons,
  Grids, DBGrids, StdCtrls, ExtCtrls, DBCtrls, MydacVcl,
{$ENDIF}
{$IFDEF CLR}
   System.ComponentModel,
{$ENDIF}
  Db, MemDS, DBAccess, DALoader, MyLoader, MyScript, MyAccess, DAScript, 
  CRAccess, DemoFrame, MyDacDemoForm, Fetch;

type
  TLoaderFrame = class(TDemoFrame)
    DataSource: TDataSource;
    Query: TMyQuery;
    MyLoader: TMyLoader;
    TruncCommand: TMyCommand;
    Panel2: TPanel;
    ToolBar: TPanel;
    btOpen: TSpeedButton;
    btClose: TSpeedButton;
    btLoad: TSpeedButton;
    btDeleteAll: TSpeedButton;
    Panel1: TPanel;
    Label1: TLabel;
    edRows: TEdit;
    DBGrid: TDBGrid;
    Panel3: TPanel;
    rgEvent: TRadioGroup;
    Panel4: TPanel;
    DBNavigator: TDBNavigator;
    procedure btOpenClick(Sender: TObject);
    procedure btCloseClick(Sender: TObject);
    procedure btLoadClick(Sender: TObject);
    procedure GetColumnData(Sender: TObject; Column: TDAColumn;
      Row: Integer; var Value: Variant; var EOF: Boolean);
    procedure btDeleteAllClick(Sender: TObject);
    procedure QueryAfterOpen(DataSet: TDataSet);
    procedure QueryBeforeClose(DataSet: TDataSet);
    procedure PutData(Sender: TDALoader);
    procedure rgEventClick(Sender: TObject);
    procedure QueryBeforeFetch(DataSet: TCustomDADataSet;
      var Cancel: Boolean);
    procedure QueryAfterFetch(DataSet: TCustomDADataSet);
  private
    { Private declarations }
  public
    PMInterval: integer;
    Count: integer;
    destructor Destroy; override;

    // Demo management
    procedure Initialize; override;
    procedure SetDebug(Value: boolean); override;
  end;

implementation

{$IFDEF CLR}
{$R *.nfm}
{$ENDIF}
{$IFDEF WIN32}
{$R *.dfm}
{$ENDIF}
{$IFDEF LINUX}
{$R *.xfm}
{$ENDIF}

destructor TLoaderFrame.Destroy;
begin
  inherited;
  FreeAndNil(FetchForm);
end;

procedure TLoaderFrame.btOpenClick(Sender: TObject);
begin
  Query.Open;
end;

procedure TLoaderFrame.btCloseClick(Sender: TObject);
begin
  Query.Close;
end;

procedure TLoaderFrame.btLoadClick(Sender: TObject);
var
  Start, Finish, Freq: Integer;
begin

  Start := GetTickCount;
  ShortDateFormat := 'yyyy-mm-dd';
  MyLoader.Connection.Connect;
  FetchForm.Show;
  Count := StrToInt(edRows.Text);
  FetchForm.ProgressBar.Max := Count;

  FetchForm.CancelLoad := False;
  try
    MyLoader.Load;  // loading rows
  finally
    FetchForm.Hide;
    Finish := GetTickCount;
    Freq := 1000;
    MyDacForm.StatusBar.Panels[2].Text := 'Time: ' + FloatToStr(Round((Finish - Start) / Freq * 100) / 100) + ' sec.';
    if Query.Active then
      Query.Refresh;
  end;
end;

procedure TLoaderFrame.GetColumnData(Sender: TObject; Column: TDAColumn;
  Row: Integer; var Value: Variant; var EOF: Boolean);
begin
  EOF := Row > Count;
  case Column.Index of
    0: Value := Row;
    1: Value := Random(100);
    2: Value := Random*100;
    3: Value := 'abc01234567890123456789';
    4: Value := Date;
  else
    Value := Null;
  end;

  FetchForm.ProgressBar.Position := Row;

  if PMInterval = 100 then begin   // 100 fields per time
    Application.ProcessMessages;
    if FetchForm.CancelLoad then begin
      MessageDlg('Loading was cancelled by user.' + #13#10
        + 'Sucessfully loaded '+ IntToStr(Row - 1) + ' rows.', mtInformation, [mbOK], 0);
      Eof := True;
    end;
  end
    else
      inc(PMInterval);
end;

procedure TLoaderFrame.PutData(Sender: TDALoader);
var
  i: integer;
begin
  PMInterval := 0;
  for i := 1 to Count do begin
    Sender.PutColumnData(0, i, i);
    Sender.PutColumnData('NUM', i, Random(100));
    Sender.PutColumnData(2, i, Random*100);
    Sender.PutColumnData(3, i, 'abc01234567890123456789');
    Sender.PutColumnData(4, i, Date);
    FetchForm.ProgressBar.Position := i;
    if PMInterval = 100 then begin // 100 records per time
      PMInterval := 0;
      Application.ProcessMessages;
      if FetchForm.CancelLoad then begin
        MessageDlg('Loading was cancelled by user.' + #13#10
          + 'Sucessfully loaded '+ IntToStr(i) + ' rows.', mtInformation, [mbOK], 0);
        Abort;
      end;
    end
    else
      inc(PMInterval);
  end;
end;

procedure TLoaderFrame.btDeleteAllClick(Sender: TObject);
begin
  TruncCommand.Execute;
  if Query.Active then
    Query.Refresh;
end;

procedure TLoaderFrame.QueryAfterOpen(DataSet: TDataSet);
begin
  MyDACForm.StatusBar.Panels[1].Text := 'Count: ' + IntToStr(DataSet.RecordCount);
end;

procedure TLoaderFrame.QueryBeforeClose(DataSet: TDataSet);
begin
  MyDACForm.StatusBar.Panels[1].Text := '';
end;

procedure TLoaderFrame.rgEventClick(Sender: TObject);
begin
  if rgEvent.ItemIndex = 0 then begin
    MyLoader.OnGetColumnData := GetColumnData;
    MyLoader.OnPutData := nil;
  end
  else begin
    MyLoader.OnGetColumnData := nil;
    MyLoader.OnPutData := PutData;
  end
end;

procedure TLoaderFrame.QueryBeforeFetch(DataSet: TCustomDADataSet;
  var Cancel: Boolean);
begin
  if DataSet.FetchingAll then begin
    FetchForm.Show;
    Application.ProcessMessages;
    Cancel := not FetchForm.Visible;

    if Cancel then
      MyDACForm.StatusBar.Panels[1].Text := 'RecordCount: ' + IntToStr(DataSet.RecordCount);
  end;
end;

procedure TLoaderFrame.QueryAfterFetch(DataSet: TCustomDADataSet);
begin
  if not DataSet.FetchingAll then begin
    FetchForm.Close;
    Application.ProcessMessages;

    MyDACForm.StatusBar.Panels[1].Text := 'RecordCount: ' + IntToStr(DataSet.RecordCount);
  end;
end;

// Demo management
procedure TLoaderFrame.Initialize;
begin
  inherited;
  if FetchForm = nil then
    FetchForm := TFetchForm.Create(MyDACForm);
  rgEvent.ItemIndex := 1;
  Query.Connection := Connection as TCustomMyConnection;
  MyLoader.Connection := Connection as TCustomMyConnection;
  TruncCommand.Connection := Connection as TCustomMyConnection;
end;

procedure TLoaderFrame.SetDebug(Value: boolean);
begin
  Query.Debug := Value;
  MyLoader.Debug := Value;
  TruncCommand.Debug := Value;
end;

end.