unit4.pas

学生成绩管理系统

unit Unit4;

interface

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

type
  TForm4 = class(TForm)
    Query1: TQuery;
    DataSource1: TDataSource;
    Button3: TButton;
    DBGrid1: TDBGrid;
    GroupBox1: TGroupBox;
    Label1: TLabel;
    DBLookupComboBox1: TDBLookupComboBox;
    DBLookupComboBox2: TDBLookupComboBox;
    Label6: TLabel;
    Label7: TLabel;
    ComboBox1: TComboBox;
    Button1: TButton;
    Edit1: TEdit;
    Label2: TLabel;
    GroupBox2: TGroupBox;
    Query2: TQuery;
    Query3: TQuery;
    DataSource2: TDataSource;
    DataSource3: TDataSource;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Label9: TLabel;
    Label10: TLabel;
    Edit2: TEdit;
    DBLookupComboBox3: TDBLookupComboBox;
    DBLookupComboBox4: TDBLookupComboBox;
    Button4: TButton;
    Query4: TQuery;
    Button2: TButton;
    Label11: TLabel;
    Memo1: TMemo;
    Label8: TLabel;
    Edit3: TEdit;
    Button5: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure Button5Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form4: TForm4;

implementation

uses Unit7;

{$R *.dfm}

procedure TForm4.Button1Click(Sender: TObject);
var s,t:string;
i:integer;
begin
    if combobox1.Text<>'' then
        begin
if (strtoint(edit1.Text)>100) or (edit1.Text='') then
begin
showmessage('请填写正确的分数');
exit;
end;

s:='select * from student.db where 成绩'+combobox1.Text+''''+edit1.Text+'''';
t:='分数'+combobox1.Text+edit1.Text;

if dblookupcombobox1.Text<>'' then
begin
s:=s+' and 班级='+''''+dblookupcombobox1.Text+'''';
t:=t+'  班级为'+dblookupcombobox1.Text;
end;
if dblookupcombobox2.Text<>'' then
begin
s:=s+' and 科目='+''''+dblookupcombobox2.Text+'''';
t:=t+'  选择科目为'+dblookupcombobox2.Text;
end;
query1.Close;
query1.SQL.Clear;
query1.sql.Add(s);
query1.Open;
i:=query1.recordcount;
t:='有'+inttostr(i)+'个学生符合条件   '+t;
memo1.text:=t;
end;
if combobox1.Text='' then
    showmessage('必须指定查询方式!');
end;

procedure TForm4.Button3Click(Sender: TObject);
begin
close;
end;


procedure TForm4.Button2Click(Sender: TObject);
begin
       if query1.Eof=false then
       begin
       form7.quickrep1.Preview;
       end
       else begin
        showmessage('请先查询数据!');
       end;
  end;

procedure TForm4.Button4Click(Sender: TObject);
var s,t:string;
begin
     s:='select  sum(成绩*学分)/sum(学分) from student.db where 成绩<=100';

     if (dblookupcombobox3.Text='') and (edit2.Text='') and (edit3.Text='') and (dblookupcombobox4.Text='') then
            t:='全部学生';
if dblookupcombobox3.Text<>'' then
begin
     s:=s+' and 科目='+''''+dblookupcombobox3.Text+'''';
     t:=t+'  课程为'+dblookupcombobox3.Text+'        ';
end;

if edit2.Text<>'' then
begin
   s:=s+'and 学号='+''''+edit2.Text+'''';
   t:=t+'  学号'+edit2.Text+'         ';
end;

if edit3.Text<>'' then
begin
   s:=s+'and 姓名='+''''+edit3.Text+'''';
   t:=t+'  姓名'+edit3.Text+'        ';
end;

if dblookupcombobox4.Text<>'' then
begin
       s:=s+' and 班级='+''''+dblookupcombobox4.Text+'''';
       t:=t+'  班级'+dblookupcombobox4.Text+'       ';
end;
      query4.Close;
      query4.SQL.Clear;
      query4.sql.Add(s);
      query4.Open;
t:=t+'平均分为:    ';
Memo1.Text:=t+query4.Fields[0].AsString;
end;

procedure TForm4.FormActivate(Sender: TObject);
begin
     query2.Active;
     query3.Active;
end;

procedure TForm4.Button5Click(Sender: TObject);
begin
     if query1.Eof=false then
       begin
       form7.quickrep1.Print;
       end
       else begin
        showmessage('请先查询数据!');
       end;
end;

end.