VC数据库操作

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VC执行存储过程

最近由于工作之需，要利用VC进行一些高级的数据库操作，如执行存储过程等。遍寻网络资源发现好使的不多（经常#30XX错误，大部分应该是COM的VARIANT数据类型所致，其实有个讨巧的方法，请看下文），在自己的实验下小有所得。记下学习笔记以备参考：

1 进行ADO编程的必备步骤：引入msado15.dll

#import "c:/program files/common files/system/ado/msado15.dll" no_namespace rename("EOF","adoEOF")//避免与文件的结束符号混淆，将EOF改为adoEOF

当然要记得在所有#include之后加入啊

2 也是必备的：初始化Com库

::CoInitialize(NULL);///初始化COM库

3 建立数据库连接

_ConnectionPtr m_pConnection;//连接数据库的Com智能指针，可以自动Release ^_^
m_pConnection.CreateInstance("ADODB.Connection");//建立实例返回HRESULT 所以最好if一下看看成功否

4 连接数据库

m_pConnection->Open("Driver={SQL Server};Server=localhost;Database=Northwind;UID=sa;PWD=wxy","","",adModeUnknown);

最好用Try的，可以捕获错误啊，例如

try
{
m_pConnection->Open("Driver={SQL Server};Server=localhost;Database=Northwind;UID=sa;PWD=wxy","","",adModeUnknown);

.........//其他数据库操作
}
catch(_com_error e)
{
//处理错误吧
}

5 创建执行存储过程的命令对象

_CommandPtr m_pCommand;//还是智能指针
m_pCommand.CreateInstance("ADODB.Command");//实例
m_pCommand->ActiveConnection = m_pConnection;//设置连接，别忘了啊
m_pCommand->CommandText = "Test";//存储过程为Test

假设我的存储过程如下：
   CREATE PROCEDURE Test
   @id int,
   @Name varchar(20),
   @sdate datetime,
   @ret char(1) output
    AS
   insert into VCStorproc values(@id,@Name,@sdate)
   if @@error=0
    set @ret=1
   else
    set @ret=0
   go

6 建立传入存储过程的参数

存储过程Test中输入参数id,name,sdate 输出参数ret 记住他们的类型和大小啊

下面就来创建4个参数

VC中用_ParameterPtr智能指针来建立参数，具体如下：

_ParameterPtr m_pParam;
m_pParam.CreateInstance("ADODB.Parameter");

_ParameterPtr m_pParam1;//附加数字的命名习惯不好别学我啊
m_pParam1.CreateInstance("ADODB.Parameter");

_ParameterPtr m_pParam2;
m_pParam2.CreateInstance("ADODB.Parameter");

_ParameterPtr m_pParamRet;
m_pParamRet.CreateInstance("ADODB.Parameter");

别高兴还没有真正的建立好参数

m_pParam = m_pCommand->CreateParameter("id",adInteger,adParamInput,-1,(_variant_t)"10");//给参数设置各属性
m_pCommand->Parameters->Append(m_pParam);//加入到Command对象的参数集属性中

m_pParam1 = m_pCommand->CreateParameter("Name",adVarChar,adParamInput,20,(_variant_t)"songwenfeng");
m_pCommand->Parameters->Append(m_pParam1);

m_pParam2 = m_pCommand->CreateParameter("sdate",adVarChar,adParamInput,32,(_variant_t)"2004-6-8");
m_pCommand->Parameters->Append(m_pParam2);

//

m_pParamRet=m_pCommand->CreateParameter("ret",adChar,adParamOutput,1);
m_pCommand->Parameters->Append(m_pParamRet);

大功告成，执行吧

m_pCommand->Execute(NULL,NULL,adCmdStoredProc);
//

数据库里已经有了一条新记录了，看看

id name sdate
10 songwenfeng 2004-6-8

7 最后一步，关闭连接，释放Com，走人！！

m_pConnection->Close();
CoUninitialize();

adAsyncConnect异步打开数据库

adConnectUnspecified同步打开数据库

void CDatabaseDlg::Onbtnquery()

{

//.udl生成连接字符串

// TODO: Add your control notification handler code here

CoInitialize(NULL);

_ConnectionPtr pConn(__uuidof(Connection));

_RecordsetPtr pRst(__uuidof(Recordset));

pConn->ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E://notepad.mdb;Mode=ReadWrite|Share Deny None;Persist Security Info=False";

pConn->Open("","","",adConnectUnspecified);

//open(连接字符串,用户名,密码,打开方式(同步/异步));

pRst=pConn->Execute("select * from notepad",NULL,adCmdText);

while(!pRst->rsEOF)

{

(((CListBox*)GetDlgItem(IDC_LIST1)))->AddString((_bstr_t)pRst->GetCollect("username"));

pRst->MoveNext();

}

pRst->Close();

pConn->Close();

pRst.Release();

pConn.Release();

CoUninitialize();

}

void CDatabaseDlg:: Onbtnquery ()

{

// TODO: Add your control notification handler code here

CoInitialize(NULL);

_ConnectionPtr pConn(__uuidof(Connection));

_RecordsetPtr pRst(__uuidof(Recordset));

pConn->ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E://notepad.mdb;Mode=ReadWrite|Share Deny None;Persist Security Info=False";

pConn->Open("","","",adConnectUnspecified);

// pRst=pConn->Execute("select * from notepad",NULL,adCmdText);

pRst->Open("select * from notepad",_variant_t((IDispatch*)pConn),adOpenDynamic,adLockOptimistic,adCmdText);

while(!pRst->rsEOF)

{

(((CListBox*)GetDlgItem(IDC_LIST1)))->AddString((_bstr_t)pRst->GetCollect("username"));

pRst->MoveNext();

}

pRst->Close();

pConn->Close();

pRst.Release();

pConn.Release();

CoUninitialize();

}

void CDatabaseDlg:: Onbtnquery ()

{

// TODO: Add your control notification handler code here

CoInitialize(NULL);

_ConnectionPtr pConn(__uuidof(Connection));

_RecordsetPtr pRst(__uuidof(Recordset));

_CommandPtr pCmd(__uuidof(Command));

pConn->ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E://notepad.mdb;Mode=ReadWrite|Share Deny None;Persist Security Info=False";

pConn->Open("","","",adConnectUnspecified);

// pRst=pConn->Execute("select * from notepad",NULL,adCmdText);

// pRst->Open("select * from notepad",_variant_t((IDispatch*)pConn),adOpenDynamic,adLockOptimistic,adCmdText);

pCmd->put_ActiveConnection(_variant_t((IDispatch*)pConn));

pCmd->CommandText="select * from notepad";

pRst=pCmd->Execute(NULL,NULL,adCmdText);

while(!pRst->rsEOF)

{

(((CListBox*)GetDlgItem(IDC_LIST1)))->AddString((_bstr_t)pRst->GetCollect("username"));

pRst->MoveNext();

}

pRst->Close();

pConn->Close();

pRst.Release();

pCmd.Release();

pConn.Release();

CoUninitialize();

}

adAsyncConnect异步打开数据库

adConnectUnspecified同步打开数据库

void CDatabaseDlg::Onbtnquery()

{

//.udl生成连接字符串

// TODO: Add your control notification handler code here

CoInitialize(NULL);

_ConnectionPtr pConn(__uuidof(Connection));

_RecordsetPtr pRst(__uuidof(Recordset));

pConn->ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E://notepad.mdb;Mode=ReadWrite|Share Deny None;Persist Security Info=False";

pConn->Open("","","",adConnectUnspecified);

//open(连接字符串,用户名,密码,打开方式(同步/异步));

pRst=pConn->Execute("select * from notepad",NULL,adCmdText);

while(!pRst->rsEOF)

{

(((CListBox*)GetDlgItem(IDC_LIST1)))->AddString((_bstr_t)pRst->GetCollect("username"));

pRst->MoveNext();

}

pRst->Close();

pConn->Close();

pRst.Release();

pConn.Release();

CoUninitialize();

}

void CDatabaseDlg:: Onbtnquery ()

{

// TODO: Add your control notification handler code here

CoInitialize(NULL);

_ConnectionPtr pConn(__uuidof(Connection));

_RecordsetPtr pRst(__uuidof(Recordset));

pConn->ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E://notepad.mdb;Mode=ReadWrite|Share Deny None;Persist Security Info=False";

pConn->Open("","","",adConnectUnspecified);

// pRst=pConn->Execute("select * from notepad",NULL,adCmdText);

pRst->Open("select * from notepad",_variant_t((IDispatch*)pConn),adOpenDynamic,adLockOptimistic,adCmdText);

while(!pRst->rsEOF)

{

(((CListBox*)GetDlgItem(IDC_LIST1)))->AddString((_bstr_t)pRst->GetCollect("username"));

pRst->MoveNext();

}

pRst->Close();

pConn->Close();

pRst.Release();

pConn.Release();

CoUninitialize();

}

void CDatabaseDlg:: Onbtnquery ()

{

// TODO: Add your control notification handler code here

CoInitialize(NULL);

_ConnectionPtr pConn(__uuidof(Connection));

_RecordsetPtr pRst(__uuidof(Recordset));

_CommandPtr pCmd(__uuidof(Command));

pConn->ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=E://notepad.mdb;Mode=ReadWrite|Share Deny None;Persist Security Info=False";

pConn->Open("","","",adConnectUnspecified);

// pRst=pConn->Execute("select * from notepad",NULL,adCmdText);

// pRst->Open("select * from notepad",_variant_t((IDispatch*)pConn),adOpenDynamic,adLockOptimistic,adCmdText);

pCmd->put_ActiveConnection(_variant_t((IDispatch*)pConn));

pCmd->CommandText="select * from notepad";

pRst=pCmd->Execute(NULL,NULL,adCmdText);

while(!pRst->rsEOF)

{

(((CListBox*)GetDlgItem(IDC_LIST1)))->AddString((_bstr_t)pRst->GetCollect("username"));

pRst->MoveNext();

}

pRst->Close();

pConn->Close();

pRst.Release();

pCmd.Release();

pConn.Release();

CoUninitialize();

}