unit1.pas

Delphi数据库编程

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Query1: TQuery;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    Label1: TLabel;
    Edit1: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
   Var
      XSXM:String;
begin
    XSXM:=Edit1.Text ;     //提取用户输入的学生姓名
    Query1.Close ;       //关闭查询结果集
    Query1.SQL.Clear ;      //清除SQL属性
    Query1.SQL.Add('Select 学生表.学号,学生表.姓名,成绩表.课程号,成绩表.成绩'); //增加SQL命令字符串
    Query1.SQL.Add('From 学生表  Inner Join 成绩表');
    Query1.SQL.Add('ON 学生表.学号=成绩表.学号');
    Query1.SQL.Add('Where 学生表.姓名=:XM'); //注意参数的前面有";"号
    Query1.Params[0].AsString :=XSXM;
    Query1.Prepare ;
    Query1.Open ;  //打开查询结果数据集
end;

end.