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HomeDatabaseMysql Tutorial关于错误 Unhandled exception in (KERNEL32.DLL):0xE06D7363:Mi

insert 后退出m_AdoConn.ExitConnect();数据库,界面关闭时报错: Unhandled exception in (KERNEL32.DLL):0xE06D7363:Microsoft C Exce 发现是上一次打开数据库后,没有关闭。关闭后,解决问题。 数据库插入 记录 方式 CString sql; ADOConn m _AdoConn; m

insert 后退出m_AdoConn.ExitConnect();数据库,界面关闭时报错:

 Unhandled exception in (KERNEL32.DLL):0xE06D7363:Microsoft C++ Exce 

发现是上一次打开数据库后,没有关闭。关闭后,解决问题。

数据库插入记录方式

CString sql;

ADOConn m_AdoConn;

m_AdoConn.OnInitADOConn();

sql.Format(_bstr_t("select * from custom"));

_RecordsetPtr m_pRecordset;

m_pRecordset=m_AdoConn.GetRecordset((_bstr_t)sql);

try

{

m_pRecordset->AddNew();

m_pRecordset->PutCollect("用户编号",_variant_t("004"));

m_pRecordset->PutCollect("用户名",_variant_t("李刚"));

m_pRecordset->PutCollect("密码",_variant_t("123456"));

m_pRecordset->Update();

m_AdoConn.ExitConnect();

 

}

catch (_com_error &e)

{

AfxMessageBox(e.Description()

)

 

 

 

  vc and access   insert 记录

 

 

一、ADO数据访问概述
ADO是Microsof非常强大的数据访问范例 OLE DB 而设计的,是一个便于使用的应用程序层接口。ADO 使您能够编写应用程序以通过 OLE. DB 提供者访问和操作数据库服务器中的数据。ADO 最主要的优点是易于使用、速度快、内存支出少和磁盘遗迹小。ADO 在关键的应用方案中使用最少的网络流量,并且在前端和数据源之间使用最少的层数,所有这些都是为了提供轻量、高性能的接口。之所以称为 ADO,是用了一个比较熟悉的暗喻,OLE 自动化接口。

OLE DB是一组”组件对象模型”(COM) 接口,是新的数据库低层接口,它封装了ODBC的功能,并以统一的方式访问存储在不同信息源中的数据。OLE DB是Microsoft UDA(Universal Data Access)策略的技术基础。OLE DB 为任何数据源提供了高性能的访问,这些数据源包括关系和非关系数据库、电子邮件和文件系统、文本和图形、自定义业务对象等等。也就是说,OLE DB 并不局限于 ISAM、Jet 甚至关系数据源,它能够处理任何类型的数据,而不考虑它们的格式和存储方法。在实际应用中,这种多样性意味着可以访问驻留在 Excel 电子数据表、文本文件、电子邮件/目录服务甚至邮件服务器,诸如 Microsoft Exchange 中的数据。但是,OLE DB 应用程序编程接口的目的是为各种应用程序提供最佳的功能,它并不符合简单化的要求。您需要的API 应该是一座连接应用程序和OLE DB 的桥梁,这就是 ActiveX Data Objects (ADO)。

二、在VC中使用ADO(开发步骤好下:

1、引入ADO库文件

使用ADO前必须在工程的stdafx.h头文件里用直接引入符号#import引入ADO库文件,以使编译器能正确编译。代码如下所示:

用#import引入ADO库文件

#import "c:\program files\common files\system\ado\msado15.dll"no_namespaces rename("EOF" adoEOF")

这行语句声明在工程中使用ADO,但不使用ADO的名字空间,并且为了避免常数冲突,将常数EOF改名为adoEOF。现在不需添加另外的头文件,就可以使用ADO接口了。

2、初始化OLE/COM库环境
必须注意的是,ADO库是一组COM动态库,这意味应用程序在调用ADO前,必须初始化OLE/COM库环境。在MFC应用程序里,一个比较好的方法是在应用程序主类的InitInstance成员函数里初始化OLE/COM库环境。

BOOL CMyAdoTestApp::InitInstance()
{
if(!AfxOleInit())//这就是初始化COM库
{
AfxMessageBox(“OLE初始化出错!”);
return FALSE;
}

……

}

3、ADO接口简介

ADO库包含三个基本接口: _ConnectionPtr接口、_CommandPtr接口和_RecordsetPtr接口。
_ConnectionPtr接口返回一个记录集或一个空指针。通常使用它来创建一个数据连接或执行一条不返回任何结果的SQL语句,如一个存储过程。使用_ConnectionPtr接口返回一个记录集不是一个好的使用方法。对于要返回记录的操作通常用_RecordserPtr来实现。而用_ConnectionPtr操作时要想得到记录条数得遍历所有记录,而用_RecordserPtr时不需要。

_CommandPtr接口返回一个记录集。它提供了一种简单的方法来执行返回记录集的存储过程和SQL语句。在使用_CommandPtr接口时,你可以利用全局_ConnectionPtr接口,也可以在_CommandPtr接口里直接使用连接串。如果你只执行一次或几次数据访问操作,后者是比较好的选择。但如果你要频繁访问数据库,并要返回很多记录集,那么,你应该使用全局_ConnectionPtr接口创建一个数据连接,然后使用_CommandPtr接口执行存储过程和SQL语句。

_RecordsetPtr是一个记录集对象。与以上两种对象相比,它对记录集提供了更多的控制功能,如记录锁定,游标控制等。同_CommandPtr接口一样,它不一定要使用一个已经创建的数据连接,可以用一个连接串代替连接指针赋给_RecordsetPtr的connection成员变量,让它自己创建数据连接。如果你要使用多个记录集,最好的方法是同Command对象一样使用已经创建了数据连接的全局_ConnectionPtr接口
,然后使用_RecordsetPtr执行存储过程和SQL语句。 

4、使用_ConnectionPtr接口
_ConnectionPtr主要是一个连接接口,取得与数据库的连接。它的连接字符串可以是自己直接写,也可以指向一个ODBC DSN。。 
_ConnectionPtr pConn;
if (FAILED(pConn.CreateInstance("ADODB.Connection")))
{
AfxMessageBox("Create Instance failed!");
return;
}


CString strSRC;
strSRC="Driver=SQL Server;Server=";
strSRC+="suppersoft";
strSRC+=";Database=";
strSRC+="mydb";
strSRC+=";UID=SA;PWD=";

CString strSQL = "Insert into student(no,name,sex,address) values(3,'aaa','male','beijing')";

_variant_t varSRC(strSRC);
_variant_t varSQL(strSQL);
_bstr_t bstrSRC(strSRC);

if (FAILED(pConn->Open(bstrSRC,"","",-1)))
{
AfxMessageBox("Can not open Database!");
pConn.Release();
return;
}

COleVariant vtOptional((long)DISP_E_PARAMNOTFOUND,VT_ERROR);

pConn->Execute(_bstr_t(strSQL),&vtOptional,-1);

pConn.Release();

AfxMessageBox("ok!");

5、使用_RecordsetPtr接口(以连接SQL Server为例)
_RecordsetPtr pPtr;
if (FAILED(pPtr.CreateInstance("ADODB.Recordset")))
{
AfxMessageBox("Create Instance failed!");
return FALSE;
}

CString strSRC;
strSRC="Driver=SQL Server;Server=";
strSRC+="210.46.141.145";
strSRC+=";Database=";
strSRC+="mydb";
strSRC+=";UID=sa;PWD=";
strSRC+="sa";

CString strSQL = "select id,name,gender,address from personal";

_variant_t varSRC(strSRC);
_variant_t varSQL(strSQL);

if(FAILED(pPtr->Open(varSQL,varSRC,adOpenStatic,adLockOptimistic,adCmdText)))
{
AfxMessageBox("Open table failed!");
pPtr.Release();
return FALSE;
}

while(!pPtr->GetadoEOF())
{
_variant_t varNo;
_variant_t varName;
_variant_t varSex;
_variant_t varAddress;

varNo = pPtr->GetCollect ("id");
varName = pPtr->GetCollect ("name");
varSex = pPtr->GetCollect ("gender");
varAddress = pPtr->GetCollect ("address");

CString strNo =(char *)_bstr_t(varNo);
CString strName =(char *)_bstr_t(varName);
CString strSex =(char *)_bstr_t(varSex);
CString strAddress =(char *)_bstr_t(varAddress);

strNo.TrimRight();
strName.TrimRight();
strSex.TrimRight();
strAddress.TrimRight();

int nCount = m_list.GetItemCount();
int nItem = m_list.InsertItem (nCount,_T(""));
m_list.SetItemText (nItem,0,strNo);
m_list.SetItemText (nItem,1,strName);
m_list.SetItemText (nItem,2,strSex);
m_list.SetItemText (nItem,3,strAddress);

pPtr->MoveNext();
}

pPtr->Close();
pPtr.Release();

6、使用_CommandPtr接口
_CommandPtr接口返回一个Recordset对象,并且提供了更多的记录集控制功能,以下代码示例了使用_CommandPtr接口的方法:

代码11:使用_CommandPtr接口获取数据
_CommandPtr pCommand;
_RecordsetPtr pRs;
pCommand.CreateInstance(__uuidof(Command));
pCommand->ActiveConnection=pConn;
pCommand->CommandText="select * from student";
pCommand->CommandType=adCmdText;
pCommand->Parameters->Refresh();
pRs=pCommand->Execute(NULL,NULL,adCmdUnknown);
_variant_t varValue = pRs->GetCollect("name");
CString strValue=(char*)_bstr_t(varValue);

7、关于数据类型转换由于COM对象是跨平台的,它使用了一种通用的方法来处理各种类型的数据,
因此Cstring 类和COM对象是不兼容的,我们需要一组API来转换COM对象和C++类型的数据。_vatiant_t和_bstr_t就是这样两种对象。它们提供了通用的方法转换COM对象和C++类型的数据。

 

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