unit1.pas

《Delphi7编程100例》代码,书配资料

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Menus, DB, DBTables, Grids, DBGrids;

type
  TForm1 = class(TForm)
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    Table1: TTable;
    Database1: TDatabase;
    MainMenu1: TMainMenu;
    Transcation: TMenuItem;
    StartTranscation1: TMenuItem;
    Commit1: TMenuItem;
    Rollback1: TMenuItem;
    N1: TMenuItem;
    Quit: TMenuItem;
    Isolation: TMenuItem;
    DirtyRead1: TMenuItem;
    ReadCmmitted1: TMenuItem;
    RepeatableRead1: TMenuItem;
    Refresh: TMenuItem;
    procedure StartTranscation1Click(Sender: TObject);
    procedure QuitClick(Sender: TObject);
    procedure DirtyRead1Click(Sender: TObject);
    procedure ReadCmmitted1Click(Sender: TObject);
    procedure RepeatableRead1Click(Sender: TObject);
    procedure RefreshClick(Sender: TObject);
    procedure Commit1Click(Sender: TObject);
    procedure Rollback1Click(Sender: TObject);
  private
    { Private declarations }
    procedure ChooseIsolation(Sender:TObject);
    procedure EnableMenuItems;
    procedure DisableMenuItems;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.ChooseIsolation(Sender:TObject);
var
  mi:TMenuItem;
begin
  mi:=(Sender as TMenuItem);
  mi.Checked:=True;
  case mi.Tag of
    0:Database1.TransIsolation:=tiDirtyRead;
    1:Database1.TransIsolation:=tiReadCommitted;
    2:Database1.TransIsolation:=tiRepeatableRead;
  end;
end;
procedure TForm1.EnableMenuItems;
begin
  StartTranscation1.Enabled:=True;
  Commit1.Enabled:=False;
  Rollback1.Enabled:=False;
end;

procedure TForm1.DisableMenuItems;
begin
  StartTranscation1.Enabled:=False;
  Commit1.Enabled:=True;
  Rollback1.Enabled:=True;
end;

procedure TForm1.QuitClick(Sender: TObject);
begin
  Close;
end;

procedure TForm1.DirtyRead1Click(Sender: TObject);
begin
  ChooseIsolation(Sender);
end;

procedure TForm1.ReadCmmitted1Click(Sender: TObject);
begin
  ChooseIsolation(Sender);
end;

procedure TForm1.RepeatableRead1Click(Sender: TObject);
begin
  ChooseIsolation(Sender);
end;

procedure TForm1.RefreshClick(Sender: TObject);
begin
  Table1.Refresh;
end;

procedure TForm1.StartTranscation1Click(Sender: TObject);
begin
  Database1.StartTransaction;
  DisableMenuItems;
end;
procedure TForm1.Commit1Click(Sender: TObject);
begin
  Database1.Commit;
  EnableMenuItems;
  Table1.Refresh;
end;

procedure TForm1.Rollback1Click(Sender: TObject);
begin
  Database1.Rollback;
  EnableMenuItems;
  Table1.Refresh;
end;

end.