querycourse.pas

delphi 学生选课系统的实现 附有sql 语句

unit QueryCourse;

interface

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

type
  TQueryCourseForm = class(TForm)
    DBGrid1: TDBGrid;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Label6: TLabel;
    Label7: TLabel;
    Label8: TLabel;
    ComboBox1: TComboBox;
    ComboBox2: TComboBox;
    Button1: TButton;
    Button2: TButton;
    procedure Button2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure OnHide(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  QueryCourseForm: TQueryCourseForm;
  str:string;

implementation

uses DataModule;

{$R *.dfm}

procedure TQueryCourseForm.Button2Click(Sender: TObject);
begin
  Edit1.Clear;
  Edit2.Clear;
  Edit3.Clear;
  Edit4.Clear;
  ComboBox1.ItemIndex := 0;
  ComboBox2.ItemIndex := 0;
end;

procedure TQueryCourseForm.Button1Click(Sender: TObject);
begin
  if ComboBox1.Text = '' then
  begin
    if ComboBox2.Text <> '' then
    begin
      str := '_'+'-'+ComboBox2.Text;
    end
  end
  else
  begin
    if ComboBox2.Text = '' then
    begin
      str := ComboBox1.Text+'-'+'_'
    end
    else
    begin
      str := ComboBox1.Text +'-'+ComboBox2.Text;
    end
  end;

  with DataModuleForm.A_Stu_QueryCourse do
  begin
    Close;
    SQL.Clear;
    SQL.Add('select * from 课程详细信息 where');
    if Edit1.Text <> '' then
    begin
      SQL.Add(' 课程号 = '+''''+Edit1.Text+'''');
    end
    else
    begin
      SQL.Add(' 课程号 = 课程号');
    end;
    if Edit2.Text <> '' then
    begin
      SQL.Add('and 课序号 = '+''''+Edit2.Text+'''');
    end
    else
    begin
      SQL.Add('and 课序号 = 课序号');
    end;
    if Edit3.Text <> '' then
    begin
      SQL.Add('and 开课学院 = '+''''+Edit3.Text+'''');
    end
    else
    begin
      SQL.Add('and 开课学院 = 开课学院');
    end;
    if Edit4.Text <> '' then
    begin
      SQL.Add('and 任课教师 = '+''''+Edit4.Text+'''');
    end
    else
    begin
      SQL.Add('and 任课教师 = 任课教师');
    end;
    if (ComboBox1.Text = '') and (ComboBox2.Text = '') then
    begin
      SQL.Add('and 上课时间 = 上课时间');
    end
    else
    begin
      SQL.Add('and 上课时间 like '+''''+str+'''');
    end;
//    Application.MessageBox(SQL.GetText,'信息',MB_OK);
    Open;
  end
end;

procedure TQueryCourseForm.OnHide(Sender: TObject);
begin
  Edit1.Clear;
  Edit2.Clear;
  Edit3.Clear;
  Edit4.Clear;
  ComboBox1.ItemIndex := 0;
  ComboBox2.ItemIndex := 0;
end;

end.