queryunit.pas

该系统为学生信息管理系统

unit queryunit;

interface

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

type
  Tdataqueryform = class(TForm)
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    RadioGroup1: TRadioGroup;
    GroupBox1: TGroupBox;
    Edit1: TEdit;
    DBGrid1: TDBGrid;
    DBNavigator1: TDBNavigator;
    Button1: TButton;
    DBGrid2: TDBGrid;
    DBNavigator2: TDBNavigator;
    Label1: TLabel;
    Label2: TLabel;
    Edit2: TEdit;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  dataqueryform: Tdataqueryform;

implementation

uses querydatamoduleunit;

{$R *.dfm}

procedure Tdataqueryform.Button1Click(Sender: TObject);
begin
   with  querydatamodule do
   begin
      case  radiogroup1.itemindex of
      0: with  studentsquery do
         begin
           close;
           if  sql.count=3 then sql.Delete(2);
           sql.Append('where sno=:tt');
           parambyname('tt').asstring:=edit1.Text;
           prepare;
           open;
           dbnavigator1.datasource:=dsstudents;
           dbgrid1.datasource:=dsstudents;
          end;
      1: with  teachersquery  do
          begin
            close;
            if sql.count=3 then sql.Delete(2);
            sql.Append('where tno=:tt');
            parambyname('tt').asstring:=edit1.Text;
            prepare;
            showmessage(inttostr(radiogroup1.itemindex));
            open;
            dbnavigator1.datasource:=dsteachers;
             dbgrid1.datasource:=dsteachers;
            end;
      2:  with coursequery do
           begin
             close;
             if sql.count=3  then  sql.Delete(2);
             sql.Append('where cno=:tt');
             parambyname('tt').asstring:=edit1.Text;
             prepare;
             open;
             dbnavigator1.datasource:=dscourse;
             dbgrid1.datasource:=dscourse;
            end;
           end;
        end;
      end;


procedure Tdataqueryform.Button2Click(Sender: TObject);
var
s:string;
begin

   with  querydatamodule.studentsquery do
   begin
       close;
       sql.clear;
        s:='select * from student where name like'+''''+edit2.Text+'%'+'''';
       //sql.add('select *');
       //sql.add('from student');
       //sql.add('where student.name like %tt%');
       sql.add(s);
       //parambyname('tt').asstring:=edit2.text;
       prepare;
       open;
       dbnavigator2.DataSource:=querydatamodule.dsstudents;
             dbgrid2.DataSource:=querydatamodule.dsstudents;
   end;
end;

end.