unitquery.pas

教务管理系统

unit UnitQuery;

interface

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

type
  TfrmQuery = class(TForm)
    GroupBox1: TGroupBox;
    dbg: TDBGrid;
    ds: TDataSource;
    qry: TADOQuery;
    GroupBox2: TGroupBox;
    memSQL: TMemo;
    btnExec: TButton;
    btnClose: TButton;
    procedure btnCloseClick(Sender: TObject);
    procedure btnExecClick(Sender: TObject);
    procedure memSQLChange(Sender: TObject);
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmQuery: TfrmQuery;

implementation

uses UnitData;

{$R *.dfm}
// 执行关闭功能
procedure TfrmQuery.btnCloseClick(Sender: TObject);
begin
  Close;
end;
 // 通过按钮“执行“完成查询功能
procedure TfrmQuery.btnExecClick(Sender: TObject);
var
  str: string;
begin
//把前六个字符与“select”进行比较
  str := LeftStr(memSQL.Lines.Strings[0], 6);
  if CompareText(str, 'select') <> 0 then begin
    application.MessageBox(PAnsiChar('请使用select进行查询！'), PAnsiChar('语句错误'), MB_OK + MB_ICONINFORMATION);
    //显示消息框
    memSQL.Clear;
    btnExec.Enabled := FALSE;
    //“执行“按钮无效
    exit;    
  end;
  qry.Close;
  qry.SQL := memSQL.Lines;
  qry.Open;
  //回显查询结果
  memSQL.Clear;
  btnExec.Enabled := FALSE;
end;

procedure TfrmQuery.memSQLChange(Sender: TObject);
begin
  btnExec.Enabled := memSQL.Lines.Count <> 0;
  // 如果输入的字符行数不为0，“执行”按钮有效
end;

procedure TfrmQuery.FormShow(Sender: TObject);
begin
  memSQL.SetFocus;
end;

end.