C API 连接MySql

编译环境：WIN7，VS2010，MYSQL版本5.0
因为VS2010自带的CRecordSet类不能与MYSQL5.0匹配，反正我的电脑上是一创建CRecordSet类VS就崩溃，
所以如果想用ODBC接口的话只能直接调用WINAPI，代码既难看又麻烦
于是根据MYSQL自带手册编写了自己的MYSQL类，调试成功，源代码如下：

/*  
 * [3/9/2012] 
 * Powered by akaka 
 * 
 * akaka_mysql_h 
 * 
 * C API连接MYSQL数据库 
 * 一、包含/include 和 /lib 
 * 二、#include<Windows.h> (不添加会导致编译时错误) 
 * 三、添加libmysql.lib 
 * 四、设置环境变量：这里直接将/lib 目录下的libmysql.dll复制到c:/windows/system32/ 目录下  
 * 
 */
#pragma once  
#include "std_lib_facilities.h"  
#include <windows.h>  
#include <mysql.h>  
  
class CMysql{    
public:  
    CMysql();  
    ~CMysql();   
    void connect(const char *host, const char *user, const char *passwd,   
        const char *db, unsigned int port, const char *unix_socket, unsigned long client_flag);  
    void query(const char *query);    
    void printinfo ();  
    void printrows ();  
  
private:  
    MYSQL* _sql;  
    MYSQL_RES* _sqlres;     // result set   
private:  
    unsigned int _column;   // how many columns in a row in "result set"  
};  

/*  
 * [3/9/2012] 
 * Powered by akaka 
 * 
 *  
 * akaka_mysql.cpp 
 */   
  
#include "akaka_mysql.h"  
  
//------------------------------------------------------------------------------  
  
CMysql::CMysql()  
{  
    if( (_sql = mysql_init(NULL)) == NULL)  
    {   throw runtime_error("failed in mysql_init!") ;}  
}  
  
CMysql::~CMysql()  
{  
    if(_sql)   
        mysql_close(_sql);  
}  
  
//------------------------------------------------------------------------------  
  
void CMysql::connect(const char *host, const char *user, const char *passwd,   
    const char *db, unsigned int port, const char *unix_socket, unsigned long client_flag)   
{  
    if (mysql_real_connect(_sql, host, user, passwd, db,  
         port, unix_socket, client_flag) == NULL)  
         throw runtime_error("failed in mysql_connect!");  
  
}  
  
//------------------------------------------------------------------------------   
void CMysql::query(const char *query)  
{  
    // mysql_query Returns:  
    // Zero if the query was successful. Non-zero if an error occurred.   
    if(mysql_query(_sql, query))  
        throw runtime_error("failed in mysql_query!");  
  
    _sqlres = mysql_store_result(_sql); // 保存结果集  
}  
  
//------------------------------------------------------------------------------    
void CMysql::printinfo()  
{  
    // count how many columns in a row in "result set"  
    _column = 0;  
       
    MYSQL_FIELD* sqlfield;  
    while(sqlfield = mysql_fetch_field(_sqlres)) //遍历字段  
    {     
        cout << '[' << sqlfield->name << ']';  
        _column++;  
    }  
    cout << endl;  
}  
  
//------------------------------------------------------------------------------    
void CMysql::printrows()  
{  
    MYSQL_ROW sqlrow;  
    while( sqlrow = mysql_fetch_row(_sqlres)) // 遍历结果集  
    {  
        for(unsigned int i = 0; i < _column; i++) // 遍历每列  
        {  
            cout << '[' << sqlrow[i] << ']';  
        }  
        cout << endl;  
    }     
}  

//------------------------------------------------------------------------------  
// main  
int main()  
{  
    const char* host = "localhost";  
    const char* user = "root";  
    const char* passwd = "1121";  
    const char* db = "my";  
    const unsigned int port = 3306;  
    const char* unix_socket = NULL; // If unix_socket is not NULL, the string specifies the socket   
                                    // or named pipe that should be used.   
                                    // Note that the host parameter determines the type of the connection.   
    const unsigned long client_flag = 0;  // The value of client_flag is usually 0, but can be set to a combination of the following flags to enable certain features:   
  
    try  
    {  
        CMysql mysql;  
        mysql.connect(host,user,passwd,db,port,unix_socket,client_flag);  
        mysql.query("SELECT * FROM myclass");  
        mysql.printinfo();  
        mysql.printrows();  
        return 0;  
    }catch(runtime_error& e)  
    {  
        cerr << e.what() << endl;  
        return 1;  
    }  
}  

运行结果：