unit2.cpp

数据库管理

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

#include <vcl.h>
#pragma hdrstop

#include "Unit2.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall TForm2::Button1Click(TObject *Sender) //查找
{

   if(Edit1->Text=="")
      MessageBox(NULL,"请输入学号","错误",MB_OK);

   else{
   int a;
   a=StrToIntDef(Edit1->Text,0);
   if(a<=0)
     {MessageBox(NULL,"输入无效","错误",MB_OK);
     Edit1->Text="";
     }
     else{
   if(Table1->Active==false)
      Table1->Open();
   Table1->IndexName="学号";
   Table1->SetKey();
   Table1->FieldByName("学号")->Value=StrToInt(Edit1->Text);
   if(!Table1->GotoKey())
      MessageBox(NULL,"不能找到","信息",MB_OK);
      else
      {
        Edit2->Text=Table1->FieldByName("学号")->Value;
        Edit3->Text=Table1->FieldByName("姓名")->Value;
        Edit4->Text=Table1->FieldByName("班级")->Value;
        Memo1->Text=Table1->FieldByName("备注")->Value;
       }
   Edit1->Text="";
   }

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

void __fastcall TForm2::Button2Click(TObject *Sender) //修改
{
   if(Table1->Active==false)
      Table1->Open();
   if(Edit2->Text=="")
      MessageBox(NULL,"请输入要修改的学号","错误",MB_OK);
   else{
    Table1->First();
     int i=0;
     while(!(Table1->Eof)&&(i==0))
     {
       if(Table1->FieldByName("学号")->Value==StrToInt(Edit2->Text))
         { Table1->Edit();
           //if(Edit3->Text!="")
            Table1->FieldByName("姓名")->Value=Edit3->Text;
            //if(Edit4->Text!="")
           Table1->FieldByName("班级")->Value=Edit4->Text;
           Table1->FieldByName("备注")->Value=Memo1->Text;
           Table1->Post();
           MessageBox(NULL,"信息已修改","信息",MB_OK);
           i++;
          }
       Table1->Next();
     }
     }
   /*Table1->Edit();
   Table1->FieldByName("姓名")->Value=Edit3->Text;
   Table1->FieldByName("班级")->Value=Edit4->Text;
   if(MessageDlg("记录"+Table1->FieldByName("学号")->AsString+"将被修改,确定？",
   mtWarning,TMsgDlgButtons()<<mbYes<<mbNo,NULL)==mbYes){
     Table1->Post();
     Table1->Active==false;} */

}
//---------------------------------------------------------------------------
void __fastcall TForm2::Button3Click(TObject *Sender) //插入
{
     if(Edit2->Text=="")
      MessageBox(NULL,"请输入学号","错误",MB_OK);
      else{
     if(Table1->Active==false)
        Table1->Open();
     Table1->First();
     int i=0;
     while(!(Table1->Eof)&&(i==0))
     {
       if(Table1->FieldByName("学号")->Value==StrToInt(Edit2->Text))
         { MessageBox(NULL,"该学号已存在","信息",MB_OK);
           i++;
          }
       Table1->Next();
     }
     if(i==0)
     {
     Table1->Insert();
     Table1->FieldByName("学号")->Value=StrToInt(Edit2->Text);
     Table1->FieldByName("姓名")->Value=Edit3->Text;
     Table1->FieldByName("班级")->Value=Edit4->Text;
     Table1->FieldByName("备注")->Value=Memo1->Text;
     Table1->Post();
     MessageBox(NULL,"该信息已插入","信息",MB_OK);
     }
}
    // Table1->Active==false;
}
//---------------------------------------------------------------------------


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


void __fastcall TForm2::Button5Click(TObject *Sender) //按班显示
{
   Table1->Close();
   Table1->IndexFieldNames="班级";
   Table1->Open();
   Table1->SetRangeStart();
   Table1->FieldByName("班级")->Value=Edit5->Text;
   Table1->SetRangeEnd();
   Table1->FieldByName("班级")->Value=Edit5->Text;
   Table1->ApplyRange();
}
//---------------------------------------------------------------------------

void __fastcall TForm2::Button6Click(TObject *Sender)//全部显示
{
      if(Table1->Active==true)
        Table1->Close();
    //Table1->Active==false;
    Table1->Open();
}
//---------------------------------------------------------------------------

void __fastcall TForm2::Button7Click(TObject *Sender)//隐藏信息
{
     if(Table1->Active==true)
        Table1->Close();
}
//---------------------------------------------------------------------------

void __fastcall TForm2::Button8Click(TObject *Sender)//退出学生信息管理
{
     Close();
}
//---------------------------------------------------------------------------


void __fastcall TForm2::Button4Click(TObject *Sender) //删除
{
  int a=0,b=0;
  if(Edit2->Text=="")
      MessageBox(NULL,"请输入要删除的学号","错误",MB_OK);
  else{

   if(Table2->Active==false)
         Table2->Open();
   Table2->IndexFieldNames="学号";
   Table2->SetKey();
   Table2->FieldByName("学号")->Value=StrToInt(Edit2->Text);
   if(!Table2->GotoKey())
       a=1;
   else a=-1;

   if(Table3->Active==false)
         Table3->Open();
   Table3->IndexFieldNames="学号";
   Table3->SetKey();
   Table3->FieldByName("学号")->Value=StrToInt(Edit2->Text);
   if(!Table3->GotoKey())
       {b=1;}
   else b=-1;

   if(a==1&&b==1){
     if(Table1->Active==false)
        Table1->Open();
     Table1->First();
     int i=0;
     while(!(Table1->Eof)&&(i==0))
     {
       if(Table1->FieldByName("学号")->Value==StrToInt(Edit2->Text))
         {//if(MessageDlg("记录"+Table1->FieldByName("学号")->AsString+"将被删除,确定？",mtWarning,TMsgDlgButtons()<<mbYes<<mbNo,NULL)==mbYes)
           Table1->Delete();
           Edit2->Text="";
           Edit3->Text="";
           Edit4->Text="";
           Memo1->Text="";
           MessageBox(NULL,"该信息已删除","信息",MB_OK);
           i++;
          }
          Table1->Next();

     }
     }
     else MessageBox(NULL,"另有表使用该信息，无法删除","信息",MB_OK);
    }
    
}

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