Java学生选课系统实验报告(7)

begin

//未选择课程时，不允许提交 if adoquery3.RecordCount=0 then begin

showmessage('请先选择一门课程'); exit; end;

num:=trim(dbgrid2.Fields[0].Text);//保存课序号

//判断所选的课程是否已选和是否与其他已经选的课程有时间冲突 adoquery1.Close; adoquery1.SQL.Clear;

adoquery1.SQL.Add('select sksjt,sksjj from KCB');

adoquery1.SQL.Add('where kcbh='''+dbgrid2.Fields[1].Text+''''); adoquery1.Open;

while not adoquery1.Eof do begin

day:=adoquery1.fieldbyname('sksjt').AsInteger; section:=adoquery1.fieldbyname('sksjj').AsInteger; adoquery2.First;

while not adoquery2.Eof do begin

//判断课程是否已选

if (trim(adoquery2.fieldbyname('kxh').AsString)=num) then begin

showmessage('所选的课程：'+trim(adoquery2.fieldbyname('kcmc').AsString)+' 已在课表中，请选择其他课程'); exit; end;

//判断课程是否与已选课程有时间冲突 if

(adoquery2.fieldbyname('sksjt').AsInteger=day)and(adoquery2.fieldbyname('sksjj').A

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sInteger=section) then begin

showmessage('

所

选

课

程

的

上

课

时

间

与

已

选

的

'+trim(adoquery2.fieldbyname('kcmc').AsString)+' 冲突!'); exit; end;

adoquery2.Next; end;

adoquery1.Next; end; //选课

adocommand1.CommandText:='insert

values('''+id+''','''+trim(dbgrid2.Fields[0].Text)+''')'; adocommand1.Execute; listcourse(id);//刷新数据表 end;

//-------------删除已选课程-------------

procedure TCourseElect.BitBtn3Click(Sender: TObject); begin

if application.MessageBox('确实删除所选课程？','确定删除',MB_OKCANCEL)=IDOK then begin

adocommand1.CommandText:='delete

from

XKB

where

into

XKB([xh],[kxh])

(xh='''+trim(dbgrid3.Fields[0].Text)+''')and(kxh='''+trim(dbgrid3.Fields[1].Text)+''')'; adocommand1.Execute; listcourse(id);//刷现列表 end; end;

procedure TCourseElect.FormClose(Sender: TObject;

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var Action: TCloseAction); begin action:=cafree; end;

procedure TCourseElect.Button1Click(Sender: TObject); begin

adoquery3.Close; adoquery3.SQL.Clear; adoquery3.SQL.Add('select

KCB.kxh,KCXX.kcbh,kcmc,js,kkxb,pym,KCB.sksjt,sksjj,skdd from KCB,KCXX where KCXX.kcbh=KCB.kcbh'); adoquery3.Open;

DBGrid2.DataSource.DataSet:=adoquery3; DBGrid2.DataSource.DataSet.Active:=false; DBGrid2.DataSource.DataSet.Active:=true; end;

procedure TCourseElect.FormShow(Sender: TObject); begin

adoquery3.Close; adoquery3.SQL.Clear; adoquery3.SQL.Add('select

XKB.kxh,KCXX.kcbh,kcmc,js,kkxb,pym,KCB.sksjt,sksjj,skdd

from

KCB,XSXX,KCXX,XKB where XKB.kxh=KCB.kxh and XKB.xh=XSXX.xh and KCXX.kcbh=KCB.kcbh'); adoquery3.Open; end; end.

图4.6 课表查询模块的系统截图

33

核心代码：

//------------根据输入的学号显示学生信息和课表------------- procedure TSchedule.Edit1KeyPress(Sender: TObject; var Key: Char); //var i,j:integer; //rt:Trect; begin

//回车输入，将学生的信息显示在文本框中 if key=#13 then begin

id:=trim(edit1.Text); adoquery1.Close; adoquery1.SQL.Clear; adoquery1.SQL.Add('select

XSXX.xh,xm,BJXX.bjmc,KCXX.kcmc,KCB.sksjt,

sksjj,skdd from KCXX,KCB,XSXX,BJXX where KCXX.kcbh=KCB.kcbh and BJXX.bjbh=XSXX.bjbh and xh='''+id+'''order by sksjt asc'); adoquery1.Open;

edit2.Text:=trim(adoquery1.fieldbyname('xm').AsString); edit3.Text:=trim(adoquery1.fieldbyname('bjmc').AsString); if adoquery1.RecordCount=0 then begin

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showmessage('学号输入错误'); edit1.Text:=''; exit; end else begin

DBGrid1.DataSource.DataSet:=adoquery1; DBGrid1.DataSource.DataSet.Active:=false; DBGrid1.DataSource.DataSet.Active:=true; end; end; end; end.

图4.7 成绩输入模块的系统截图

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