unit3.cpp

数据库管理

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit3.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm3 *Form3;
//---------------------------------------------------------------------------
__fastcall TForm3::TForm3(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall TForm3::Button1Click(TObject *Sender) //显示学生成绩
{
   if(Edit1->Text=="")
      MessageBox(NULL,"请输入学号","错误",MB_OK);
   else{
   Table1->Close();
   Table1->IndexFieldNames="学号";
   Table1->Open();
   Table1->SetRangeStart();
   Table1->FieldByName("学号")->Value=StrToInt(Edit1->Text);
   Table1->SetRangeEnd();
   Table1->FieldByName("学号")->Value=StrToInt(Edit1->Text);
   Table1->ApplyRange();
   }
}
//---------------------------------------------------------------------------

void __fastcall TForm3::Button6Click(TObject *Sender) //显示学期内成绩
{
   if(Edit5->Text=="")
      MessageBox(NULL,"请输入学期","错误",MB_OK);
      else{
   Table1->Close();
   Table1->IndexFieldNames="学期";
   Table1->Open();
   Table1->SetRangeStart();
   Table1->FieldByName("学期")->Value=(Edit5->Text);
   Table1->SetRangeEnd();
   Table1->FieldByName("学期")->Value=(Edit5->Text);
   Table1->ApplyRange();
   }
}
//---------------------------------------------------------------------------
void __fastcall TForm3::Button5Click(TObject *Sender)//退出
{
    Close();
}
//---------------------------------------------------------------------------
void __fastcall TForm3::Button2Click(TObject *Sender) //插入英语成绩
{
    if(Edit2->Text=="")
      MessageBox(NULL,"请输入学号","错误",MB_OK);
    else{
     if(Table2->Active==false)
        Table2->Open();
     Table2->First();
     int i=0;
     while(!(Table2->Eof)&&(i==0))
     {
       if(Table2->FieldByName("学号")->Value==StrToInt(Edit2->Text)&&Table2->FieldByName("学期")->Value==Edit4->Text)
         { ShowMessage("该学生本学期成绩已存在,要修改请选修改");
           i++;
          }
       Table2->Next();
     }
     if(i==0)
     {
     Table2->Insert();
     Table2->FieldByName("学号")->Value=StrToInt(Edit2->Text);
     if(Edit3->Text=="")
     Edit3->Text="0";
     Table2->FieldByName("成绩")->Value=StrToFloat(Edit3->Text);
     Table2->FieldByName("学期")->Value=Edit4->Text;
     Table2->Post();
     MessageBox(NULL,"该信息已插入","信息",MB_OK);
     Table1->Close();
     }
}
     Table1->Open();

}
//---------------------------------------------------------------------------
void __fastcall TForm3::Button3Click(TObject *Sender)//删除英语成绩
{
    if(Edit2->Text=="")
      MessageBox(NULL,"请输入要删除的学号","错误",MB_OK);
    if(Edit4->Text=="")
      MessageBox(NULL,"请输入要删除的学期","错误",MB_OK);
    else{
     if(Table2->Active==false)
        Table2->Open();
     Table2->First();
     int i=0;
     while(!(Table2->Eof)&&(i==0))
     {
       if(Table2->FieldByName("学号")->Value==StrToInt(Edit2->Text)&&Table2->FieldByName("学期")->Value==Edit4->Text)
         {//if(MessageDlg("记录"+Table2->FieldByName("学号")->AsString+Table2->FieldByName("学期")->AsString+"成绩将被删除,确定？",
            //         mtWarning,TMsgDlgButtons()<<mbYes<<mbNo,NULL)==mbYes)
          // {
           Table2->Delete();
           Edit2->Text="";
           Edit3->Text="";
           Edit4->Text="";
           MessageBox(NULL,"该信息已删除","信息",MB_OK);
           Table1->Close();
          //}
           i++;
          }
       Table2->Next();

     }

    }
    Table1->Open();

}
//---------------------------------------------------------------------------

void __fastcall TForm3::Button4Click(TObject *Sender) //修改英语成绩
{
    if(Table2->Active==false)
       Table2->Active=true;
    if(Edit2->Text==""||Edit3->Text==""||Edit4->Text=="")
       MessageBox(NULL,"请输入完整信息","信息",MB_OK);
    else{
        Table2->First();
        int i=0;
        while(!(Table2->Eof)&&i==0)
        {
            Table2->Edit();
            if(Table2->FieldByName("学号")->Value==StrToInt(Edit2->Text)&&Table2->FieldByName("学期")->Value==Edit4->Text)
              {
                 Table2->FieldByName("成绩")->Value=StrToFloat(Edit3->Text);
                 //if(MessageDlg("记录"+Table2->FieldByName("学号")->AsString+Table2->FieldByName("学期")->AsString+"成绩将被修改,确定？",
                 //    mtWarning,TMsgDlgButtons()<<mbYes<<mbNo,NULL)==mbYes)
                  // {
                       Table2->Post();
                       MessageBox(NULL,"成绩已修改","信息",MB_OK);
                       Table1->Close();
                    //}
                   i++;
              }
              Table2->Next();
        }

        Table1->Open();

    }

}
//---------------------------------------------------------------------------

void __fastcall TForm3::Button7Click(TObject *Sender)
{
   if(Table1->Active==true)
      Table1->Close();
   Table1->Open();

}
//---------------------------------------------------------------------------