Mysql API之C++封装(一)

由于项目要求原因，需要用C或者C++调用mysql的API接口来操作mysql数据库，在google和百度上搜了一下，发现两个比较mini的接口类，感觉比较不错，下载下来编译了一下，改了一些错误，源码如下：
DBClient.h ------

#ifndef __DB_CLIENT_H__
#define __DB_CLIENT_H__

#include <mysql.h>
#include <stdlib.h>
#include <string.h>

/**
* @brief enumaration for sql cmd type
*/
enum Cmd
{
	CMD_SELECT,
	CMD_INSERT,
	CMD_DELETE,
	CMD_UPDATE
};

#define MAX_CHAR_LEN 64

/**
* @brief this is a class for operating the mysql database
*/
class DBClient
{
public:
	  DBClient(): m_usDBPort(0), m_pResultSet(NULL)
	  {
		  memset(m_szDBIP, 0, sizeof(m_szDBIP));
		  memset(m_szUserName, 0, sizeof(m_szUserName));
		  memset(m_szPassword, 0, sizeof(m_szPassword));
		  memset(m_szDBName, 0, sizeof(m_szDBName));
	  }

	  ~DBClient()
	  {
		  FreeResultSet();
		  mysql_close(&m_oDBHandle);
	  }

	  /**
	  * @brief initialize the db connection info
	  * @param pDBIP, the db ip address
	  * @param usDBPort, the db port
	  * @param pDBName, the db name
	  * @param pUserName, the db username
	  * @param pPassword, the db password
	  * @return true if init success, otherwise, false
	  */
	  bool Init(const char * pDBIP, unsigned short usDBPort,
		  const char * pDBName, const char * pUserName, 
		  const char * pPassword);

	  /**
	  * @brief connect the db server
	  * @return true if connect success, otherwise, false
	  */
	  bool Connect();

	  /**
	  * @brief execute the sql statement
	  * @param pSqlStr, the sql statement pointer
	  * @return true if execute success, otherwise, false
	  */
	  bool Execute(const char * pSqlStr, Cmd eCmd);

	  /**
	  * @brief get the next result of the operation
	  * @param pRes, the result row
	  * @param pLen, the array of the length of every fields
	  * @param nNum, the num of fields
	  * @return true if get the next result success, otherwise, false
	  */
	  bool GetNextResult(char **& pRes, unsigned long *& pLen, 
		  int & nNum);

	  /**
	  * @brief get the most recent error No.
	  */
	  unsigned int GetErrorNo()
	  {
		  return mysql_errno(&m_oDBHandle);
	  }
private:
	/**
	* @brief free the memory of the result set
	*/
	void FreeResultSet();
private:
	/*db ip address*/
	char m_szDBIP[MAX_CHAR_LEN];
	/*db port*/
	unsigned short m_usDBPort;
	/*db name*/
	char m_szDBName[MAX_CHAR_LEN];
	/*db username*/
	char m_szUserName[MAX_CHAR_LEN];
	/*db user's password*/
	char m_szPassword[MAX_CHAR_LEN];
	/*the db connection handle object*/
	MYSQL m_oDBHandle;
	/*the pointer of result set for operating's result*/
	MYSQL_RES * m_pResultSet;
};
#endif // __DB_CLIENT_H__

DBClient.cpp实现如下：

#include "DBClient.h"
#include <string.h>

#pragma comment(lib, "libmysql.lib")

bool DBClient::Init(const char * pDBIP, unsigned short usDBPort,
		const char * pDBName, const char * pUserName,
	         const char * pPassword)
{
	strcpy(m_szDBIP, pDBIP);
	m_usDBPort = usDBPort;
	strcpy(m_szDBName, pDBName);
	strcpy(m_szUserName, pUserName);
	strcpy(m_szPassword, pPassword);
	if (NULL == mysql_init(&m_oDBHandle))
	{
		return false;
	}
	return true;
}

bool DBClient::Connect()
{
	if (NULL == mysql_real_connect(&m_oDBHandle, m_szDBIP,
		m_szUserName, m_szPassword,
		m_szDBName, m_usDBPort,
		NULL, 0))
	{
		return false;
	}
	return true;
}

bool DBClient::Execute(const char * pSqlStr, Cmd eCmd)
{
	if (0 != mysql_query(&m_oDBHandle, pSqlStr))
	{
		return false;
	}

	if (CMD_SELECT == eCmd)
	{
		FreeResultSet();
		if (NULL == (m_pResultSet = mysql_store_result(&m_oDBHandle)))
		{
			return false;
		}
	}
	return true;
}

bool DBClient::GetNextResult(char **& pRes, unsigned long *& pLen, 
							 int & nNum)
{	
	MYSQL_ROW pRow = mysql_fetch_row(m_pResultSet);
	if(NULL == pRow)
	{
		return false;
	}
	pRes = pRow;
	nNum = mysql_num_fields(m_pResultSet);
	pLen = mysql_fetch_lengths(m_pResultSet);
	return true;
}

void DBClient::FreeResultSet()
{
	if (NULL != m_pResultSet)
	{
		mysql_free_result(m_pResultSet);
	}
	m_pResultSet = NULL;
}

接口比较简洁明快，如果你感觉功能比较简单的话，可以下载开源的SQLAPI++，我这有拷贝，需要的可以给我的邮箱发邮件，我的邮箱lppchina@gmail.com 阅读更多