unit3.pas

Delphi_7.0数据库开发源代码。有内容十一章节

unit Unit3;

interface

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

type
  TForm1 = class(TForm)
    Query1: TQuery;
    DBGrid1: TDBGrid;
    DataSource1: TDataSource;
    Start: TButton;
    Edit1: TEdit;
    Label1: TLabel;
    procedure StartClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.StartClick(Sender: TObject);
begin
Query1.Close;
Query1.SQL.Clear;
Query1.SQL.Add('SELECT 学号');
Query1.SQL.Add('FROM classmates');
Query1.SQL.Add('WHERE 年龄<:number');
Query1.Params[0].AsString:=Edit1.Text;

Query1.Prepare;
Query1.Open;
end;

end.