unit4.~pas

简单的一个computer系统

unit Unit4;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,StdCtrls, Grids, DBGrids,Unit3, ExtCtrls;

type
  TForm4 = class(TForm)
    DBGrid1: TDBGrid;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    GroupBox1: TGroupBox;
    CheckBox1: TCheckBox;
    CheckBox4: TCheckBox;
    Edit1: TEdit;
    Label1: TLabel;
    Label4: TLabel;
    Edit4: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);

  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form4: TForm4;

implementation


{$R *.dfm}

procedure TForm4.Button1Click(Sender: TObject);        //连接
begin
  dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Clear;
  dm.ADOQuery3.SQL.Add('select * from dnxx');
  dm.ADOQuery3.Open;

 self.DBGrid1.DataSource:=dm.DataSource3;
end;

procedure TForm4.Button2Click(Sender: TObject);  //查询
var
sqlstr:string;
begin

 if (self.CheckBox1.Checked=false) and
     (self.CheckBox4.Checked=false) then
    sqlstr:=''
  else
  begin
    sqlstr:='where  ';
    if self.CheckBox1.Checked=true then
      sqlstr:=sqlstr+'电脑编号='''+trim(self.Edit1.Text)+''' and  ';
    if self.CheckBox1.Checked=true then
      sqlstr:=sqlstr+'电脑价格='''+self.Edit4.Text+''' and ';
      sqlstr:=sqlstr+'1=1';
  end;

  dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Text:='select * from dnxx '+sqlstr;
  dm.ADOQuery3.Open;

  self.DBGrid1.DataSource:=dm.DataSource3;
end;

procedure TForm4.Button5Click(Sender: TObject);    //修改
begin
try
  dm.ADOConnection1.Open();
  dm.ADOConnection1.BeginTrans;
  dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Text:='update  dnxx set电脑编号=电脑编号+1 where 价格='+self.Edit4.Text;
  dm.ADOQuery3.ExecSQL;

  dm.ADOConnection1.CommitTrans;
  showmessage('成功');
  except
  dm.ADOConnection1.RollbackTrans;
  showmessage('失败');
 end
end;

procedure TForm4.Button3Click(Sender: TObject);//增加
begin
begin
if self.Edit1.Text='' then
begin
  showmessage('为空');
  exit;
end;
  dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Text:='select * from dnxx where 电脑编号='+self.Edit1.Text;
  dm.ADOQuery3.Open;
  if not(dm.ADOQuery3.IsEmpty) then
begin
  showmessage('用户已存在');
  exit;
end;
  dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Text:='insert into dnxx(电脑编号,价格)values('+self.Edit1.Text+','''+self.Edit4.Text+''')';
  dm.ADOQuery3.ExecSQL;
  dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Text:='select * from dnxx';

  self.DBGrid1.DataSource:=dm.DataSource3;
end;
end;
procedure TForm4.Button4Click(Sender: TObject);    //删除
begin
dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Text:='delete from  dnxx where 电脑编号='+self.Edit1.Text;
  dm.ADOQuery3.ExecSQL;
  dm.ADOQuery3.Close;
  dm.ADOQuery3.SQL.Text:='select * from dnxx ';
  dm.ADOQuery3.Open;
  self.DBGrid1.DataSource:=dm.DataSource3;
end;
end.