lib_query.~pas

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unit lib_query;

interface

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

type
  Tlibquery = class(TForm)
    DBGrid1: TDBGrid;
    DataSource1: TDataSource;
    Query1: TQuery;
    Panel1: TPanel;
    Label1: TLabel;
    Edit1: TEdit;
    Button3: TButton;
    Button2: TButton;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  libquery: Tlibquery;

implementation

{$R *.dfm}

procedure Tlibquery.Button1Click(Sender: TObject);

begin
     // query1.Close;
    query1.SQL.Clear;
    query1.SQL.Add('select * from questionlib where subject = '''+Edit1.Text+'''');
     // Query1.Prepare;
     // Query1.ParamByName('subject').AsString:=edit1.Text;
    Query1.Open;
    if(Query1.IsEmpty ) then
    begin
    ShowMessage('没有这个科目！');
    query1.Active:=false;
    end;
end;

procedure Tlibquery.Button3Click(Sender: TObject);
begin
self.Close;
end;

procedure Tlibquery.Button2Click(Sender: TObject);
begin
    query1.SQL.Clear;
    query1.SQL.Add('select * from questionlib ');
    Query1.Open;
end;

end.