c++连接数据库

c++连接数据库

#include <iostream>
#include "windows.h"
#include "sqlext.h"
using namespace std;
int main(){  
    SQLHENV henv;  
    SQLHDBC hdbc;  
    SQLRETURN retcode;  
    SQLTCHAR ConnStrOut[256]; 
    SQLTCHAR ConnStr[256] = L"DSN=DNS-MMLRESOLVE;UID=sa;PWD=850414";  
    SQLSMALLINT ConnStrOutLen;  
    SQLAllocHandle(SQL_HANDLE_ENV,SQL_NULL_HANDLE,&henv);  
    SQLSetEnvAttr(henv,SQL_ATTR_ODBC_VERSION,(void*)SQL_OV_ODBC3,0);
    SQLAllocHandle(SQL_HANDLE_DBC,henv,&hdbc); 
    retcode = SQLDriverConnect(hdbc,NULL,ConnStr,SQL_NTS,ConnStrOut,   sizeof(ConnStrOut),&ConnStrOutLen,SQL_DRIVER_NOPROMPT);
    if(retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO){  
        cout << "ok" << endl;   
        cout << ConnStrOutLen << endl;  
        cout << ConnStrOut << endl;  
    }
    getchar();
 
    return 0;
}

注意： 

const char to SQLCHAR

SQLCHAR* query = L"SELECT tblIP.[IPAddress], tblIP.[IPStatus], tblIP.[IPType] FROM tblIP ORDER BY tblIP.[IPAddress] ASC;";