// BookRDlg.cpp : implementation file
//

#include "stdafx.h"
#include "test.h"
#include "BookRDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CBookRDlg dialog


CBookRDlg::CBookRDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CBookRDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CBookRDlg)
	m_bookid = _T("");
	//}}AFX_DATA_INIT
}


void CBookRDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CBookRDlg)
	DDX_Text(pDX, IDC_BOOKID, m_bookid);
	//}}AFX_DATA_MAP
}


BEGIN_MESSAGE_MAP(CBookRDlg, CDialog)
	//{{AFX_MSG_MAP(CBookRDlg)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CBookRDlg message handlers

void CBookRDlg::OnOK() 
{
	// TODO: Add extra validation here
	UpdateData(true);					//数据更新
	if(m_bookid=="")
	{
		AfxMessageBox("请填入书籍ID号码");		//书籍的ID为空，则弹出消息框
		return;
	}
	CoInitialize(NULL);
	_ConnectionPtr pconnect(__uuidof(Connection));
	_RecordsetPtr record(__uuidof(Recordset));
	_CommandPtr comd(__uuidof(Command));
	pconnect->ConnectionString="Provider=MSDASQL.1;Persist Security Info=False;User ID=Administrator;Data Source=student;Initial Catalog=Library";
	pconnect->Open("","","",NULL);
	comd->put_ActiveConnection(_variant_t((IDispatch *)pconnect));
	//输入数据的合法性验证，即是否在存储表中有记录
	CString cmd="SELECT count(*) FROM  READBOOK WHERE BID='";
	cmd+=m_bookid;
	cmd+="'";	
	comd->CommandText=_bstr_t(cmd);						//得到SQL语句
	record=comd->Execute(NULL,NULL,adCmdText);			//查询记录
	variant_t vCount = record->GetCollect((_variant_t)((long)0));
	//如果记录不是唯一的，那么有可能没有记录，或者记录不止一条
	if(vCount.lVal==0)		
	{
		AfxMessageBox("数据库中无此记录");
		return;
	}
	//如果记录不是唯一的，那么有可能没有记录，或者记录不止一条
	if(vCount.lVal>1) 
	{
		AfxMessageBox("数据库错误,记录大于1");
		return;
	}
	
	//进行数据存储
	cmd="DELETE FROM  READBOOK WHERE BID='";
	cmd+=m_bookid;
	cmd+="'";	
	comd->CommandText=_bstr_t(cmd);					//得到SQL语句
	record=comd->Execute(NULL,NULL,adCmdText);			//修改数据库
	AfxMessageBox("还书成功");
	//将此书的存储状态设置为不可借
	cmd="UPDATE BOOK SET BSTATE='可借' WHERE BID='";
	cmd+=m_bookid;
	cmd+="'";
	comd->CommandText=_bstr_t(cmd);					//得到SQL语句
	record=comd->Execute(NULL,NULL,adCmdText);			//修改书籍状态为可借
	pconnect->Close();
	comd.Release();
	record.Release();
	pconnect.Release();
	CoUninitialize();
	m_bookid="";
	UpdateData(false);
}