unit1.~pas

查询类的范例

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, StdCtrls, Buttons, Mask, DBCtrls, Grids, DBGrids, ADODB,
  ComCtrls, ToolWin, ImgList, Menus;

type
  TForm1 = class(TForm)
    ADOConnection1: TADOConnection;
    ADOQuery1: TADOQuery;
    GroupBox2: TGroupBox;
    DBGrid1: TDBGrid;
    DataSource1: TDataSource;
    ImageList1: TImageList;
    BitBtn2: TBitBtn;
    GroupBox1: TGroupBox;
    BitBtn3: TBitBtn;
    Label2: TLabel;
    BitBtn1: TBitBtn;
    Edit1: TEdit;
    procedure BitBtn2Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn3Click(Sender: TObject);
    procedure Edit1KeyPress(Sender: TObject; var Key: Char);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TForm1.BitBtn2Click(Sender: TObject);
begin
  close;
end;

procedure TForm1.FormShow(Sender: TObject);
begin
  edit1.Text := '';
  with ADOQuery1 do
  begin
    close;
    SQL.Clear;
    SQL.Add('select * from COMM');
    open;
  end;
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
//var
  //Byear : string;
begin
  if length(Trim(edit1.Text))=8 then
  begin
    with ADOQuery1 do
    begin
      close;
      SQL.Clear;
      SQL.Add('select * from COMM where year(入学时间)='+Trim(edit1.Text));
      open;
    end;
    if ADOQuery1.RecordCount>0 then
      showmessage('查询成功')
    else
    begin
      showmessage('查询失败');
      FormShow(Sender);
    end;
  end
  else
  begin
    showmessage('查询时间的标准格式应为：如2006-9-10');
    edit1.Text := '';
  end;
end;

procedure TForm1.BitBtn3Click(Sender: TObject);
begin
  ADOQuery1.Cancel;
  FormShow(Sender);
end;

procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
  if not (key in ['0'..'9',#8]) then
    key := #0;
end;

end.