datasource.cpp

VC数据库通用模块及典型系统开发配套代码,包含完整例子,各模块在开发数据库的时候可以直接用

// DataSource.cpp: implementation of the CDataSource class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "DBView.h"
#include "DataSource.h"

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

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CDataSource::CDataSource()
{

}

CDataSource::~CDataSource()
{
	FreeData();
}

void CDataSource::InitData()
{
	//初始化Com对象，为使用ADO做准备
	CoInitialize(NULL);

	//初始化连接对象
	m_pConn.CreateInstance("ADODB.Connection");
	//初始化记录集对象
	m_pRecordset.CreateInstance("ADODB.Recordset");
	try
	{
		//打开数据库连接
		m_pConn->Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Demo.mdb;Persist Security Info=False", "", "", adConnectUnspecified);
		
		//初始化m_MaxID
		m_pRecordset->Open("Select Max(ID) as MAXID From Profile", _variant_t(m_pConn, true), adOpenStatic, adLockOptimistic, adCmdText);		
		m_MaxID = GetAsInteger("MAXID");
		m_pRecordset->Close();

		//打开指定记录集
		m_pRecordset->Open("Select * From Profile", _variant_t(m_pConn, true), adOpenStatic, adLockOptimistic, adCmdText);
	}
	catch(_com_error &e)
	{
		::AfxMessageBox(e.ErrorMessage());
	}
}

void CDataSource::FreeData()
{
	if (m_pConn)
	{
		m_pConn->Close();
		m_pRecordset.Release();
		m_pConn.Release();
		CoUninitialize();
	}
}

void CDataSource::MoveFirst()
{
	m_pRecordset->MoveFirst();
}

void CDataSource::MoveLast()
{
	m_pRecordset->MoveLast();
}

void CDataSource::MovePrev()
{
	m_pRecordset->MovePrevious();
}

void CDataSource::MoveNext()
{
	m_pRecordset->MoveNext();
}

BOOL CDataSource::IsFirst()
{
	if (m_pRecordset->BOF)
	{
		return TRUE;
	}
	else
	{
		m_pRecordset->MovePrevious();
		BOOL Result = m_pRecordset->BOF;
		m_pRecordset->MoveNext();
		return Result;
	}
}

BOOL CDataSource::IsLast()
{
	if (m_pRecordset->EndOfFile)
	{
		return TRUE;
	}
	else
	{
		m_pRecordset->MoveNext();
		BOOL Result = m_pRecordset->EndOfFile;
		m_pRecordset->MovePrevious();
		return Result;
	}
}

CString CDataSource::GetAsString(CString FieldName)
{
	//如果在第一条记录之前或者最后一条记录之后，返回空
	if (IsBOF() || IsEOF())
		return "";
	
	LPTSTR lpFieldName = FieldName.GetBuffer(FieldName.GetLength());
	
	//得到当前记录指定列的值
	_variant_t vValue = m_pRecordset->Fields->Item[lpFieldName]->Value;

	//如果为空值则返回空
	if ((V_VT(&vValue) == VT_NULL) || (V_VT(&vValue) == VT_EMPTY))
	{
		return "";
	}
	//否则以字符串形式返回vValue的值
	else
	{
		CString strResult;
		LPTSTR lpResult = strResult.GetBuffer(strlen(_bstr_t(vValue)));
		strcpy(lpResult, _bstr_t(vValue));
		strResult.ReleaseBuffer();
		return strResult;
	}
}

int CDataSource::GetAsInteger(CString FieldName)
{
	//如果在第一条记录之前或者最后一条记录之后，返回0
	if (IsBOF() || IsEOF())
		return 0;
	LPTSTR lpFieldName = FieldName.GetBuffer(FieldName.GetLength());
	
	//得到当前记录指定列的值
	_variant_t vValue = m_pRecordset->Fields->Item[lpFieldName]->Value;
	
	//如果为空值则返回空
	if (V_VT(&vValue) == VT_NULL)
	{
		return 0;
	}

	//否则以int形式返回vValue的值
	else
	{
		return atoi(_bstr_t(vValue));
	}
}

void CDataSource::New()
{
	//添加一条新的记录
	m_pRecordset->AddNew();

	//设置初始值
	m_MaxID++;
	SetAsInteger("ID", m_MaxID);
	SetAsString("NAME", "无名氏");
	SetAsInteger("GENDER", 0);
	SetAsInteger("AGE", 24);
	SetAsString("NATIONALITY", "汉");
	SetAsString("ADDRESS", "");
	SetAsString("POSTCODE", "");
	SetAsString("NOTE", "");
	
	//更新
	m_pRecordset->Update();
}

void CDataSource::Update()
{
	m_pRecordset->Update();
}

void CDataSource::SetAsString(CString FieldName, CString Value)
{
	//将列名（FieldName）由CString转为LPTSTR型
	LPTSTR lpFieldName = FieldName.GetBuffer(FieldName.GetLength());
	
	//将Value由CString转为LPTSTR型
	LPTSTR lpValue = Value.GetBuffer(Value.GetLength());
	
	//将Value值更新到Recordset中
	m_pRecordset->Fields->Item[lpFieldName]->Value = lpValue;

	//释放缓冲区
	FieldName.ReleaseBuffer();	
	Value.ReleaseBuffer();	
}

void CDataSource::SetAsInteger(CString FieldName, int Value)
{
	CString cs;
	
	//将Value由int型转为CString型
	cs.Format("%d", Value);

	//使用SetAsString设置指定列的值
	SetAsString(FieldName, cs);
}

void CDataSource::Delete()
{
	//删除当前记录
	m_pRecordset->Delete(adAffectCurrent);	
}

BOOL CDataSource::IsBOF()
{
	return m_pRecordset->BOF;
}

BOOL CDataSource::IsEOF()
{
	return m_pRecordset->EndOfFile;
}