C++利用MySQL API连接和操作数据库实例详解

//mysqlhelper.h

#ifndef __MYSQL_HELPER_H__
#define __MYSQL_HELPER_H__

#include <stdlib.h>

#include <map>
#include <vector>
#include <string>
using namespace std;

#include <mysql.h>

namespace mysqlhelper
{

/*********************
*@brief 数据库异常类
**********************/
struct MysqlHelper_Exception //: public TC_Exception
{
 MysqlHelper_Exception(const string &sBuffer):errorInfo(sBuffer){}; //: TC_Exception(sBuffer){};
 ~MysqlHelper_Exception() throw(){}; 

 string errorInfo;
};

/***********************
* @brief 数据库配置接口
***********************/
struct DBConf
{

 string _host;//主机地址
 string _user; //用户名 
 string _password;//密码
 string _database; //数据库
 string _charset; //字符集
 int _port;//端口
 int _flag; //客户端标识

 /*****************
 * @brief 构造函数
 *****************/
 DBConf():_port(0), _flag(0){}

 /**********************************
 * @brief 读取数据库配置. 
 * @param mpParam 存放数据库配置的map 
 * dbhost: 主机地址
 * dbuser:用户名
 * dbpass:密码
 * dbname:数据库名称
 * dbport:端口
 **********************************/
 void loadFromMap(const map<string, string> &mpParam)
 {
 map<string, string> mpTmp = mpParam;

 _host = mpTmp["dbhost"];
 _user = mpTmp["dbuser"];
 _password = mpTmp["dbpass"];
 _database = mpTmp["dbname"];
 _charset = mpTmp["charset"];
 _port = atoi(mpTmp["dbport"].c_str());
 _flag = 0;

 if(mpTmp["dbport"] == "")
 {
 _port = 3306;
 }
 }
};

/**************************************************************
* @brief:MySQL数据库操作类 
* @feature:非线程安全，通常一个线程一个MysqlHelper对象；
* 对于insert/update可以有更好的函数封装，保证SQL注入；
* MysqlHelper::DB_INT表示组装sql语句时，不加””和转义；
* MysqlHelper::DB_STR表示组装sql语句时，加””并转义；
**************************************************************/
class MysqlHelper{

public:
 /**
 * @brief 构造函数
 */
 MysqlHelper();

 /**
 * @brief 构造函数. 
 * @param: sHost:主机IP
 * @param sUser 用户
 * @param sPasswd 密码
 * @param sDatebase 数据库
 * @param port 端口
 * @param iUnixSocket socket
 * @param iFlag 客户端标识
 */
 MysqlHelper(const string& sHost, const string& sUser = "", const string& sPasswd = "", const string& sDatabase = "", const string &sCharSet = "", int port = 0, int iFlag = 0);

 /**
 * @brief 构造函数. 
 * @param tcDBConf 数据库配置
 */
 MysqlHelper(const DBConf& tcDBConf);

 /**
 * @brief 析构函数.
 */
 ~MysqlHelper();

 /**
 * @brief 初始化. 
 * 
 * @param sHost 主机IP
 * @param sUser 用户
 * @param sPasswd 密码
 * @param sDatebase 数据库
 * @param port 端口
 * @param iUnixSocket socket
 * @param iFlag 客户端标识
 * @return 无
 */
 void init(const string& sHost, const string& sUser = "", const string& sPasswd = "", const string& sDatabase = "", const string &sCharSet = "", int port = 0, int iFlag = 0);

 /**
 * @brief 初始化. 
 * 
 * @param tcDBConf 数据库配置
 */
 void init(const DBConf& tcDBConf);

 /**
 * @brief 连接数据库. 
 * 
 * @throws MysqlHelper_Exception
 * @return 无
 */
 void connect();

 /**
 * @brief 断开数据库连接. 
 * @return 无
 */
 void disconnect();

 /**
 * @brief 获取数据库变量. 
 * @return 数据库变量
 */
 string getVariables(const string &sName);

 /**
 * @brief 直接获取数据库指针. 
 * 
 * @return MYSQL* 数据库指针
 */
 MYSQL *getMysql();

 /**
 * @brief 字符转义. 
 * 
 * @param sFrom 源字符串
 * @param sTo 输出字符串
 * @return 输出字符串
 */
 string escapeString(const string& sFrom);

 /**
 * @brief 更新或者插入数据. 
 * 
 * @param sSql sql语句
 * @throws MysqlHelper_Exception
 * @return
 */
 void execute(const string& sSql);

 /**
 * @brief mysql的一条记录
 */
 class MysqlRecord
 {
 public:
 /**
 * @brief 构造函数.
 * 
 * @param record
 */
 MysqlRecord(const map<string, string> &record);

 /**
 * @brief 获取数据，s一般是指数据表的某个字段名 
 * @param s 要获取的字段
 * @return 符合查询条件的记录的s字段名
 */
 const string& operator[](const string &s);
 protected:
 const map<string, string> &_record;
 };

 /**
 * @brief 查询出来的mysql数据
 */
 class MysqlData
 {
 public:
 /**
 * @brief 所有数据.
 * 
 * @return vector<map<string,string>>&
 */
 vector<map<string, string> >& data();

 /**
 * 数据的记录条数
 * 
 * @return size_t
 */
 size_t size();

 /**
 * @brief 获取某一条记录. 
 * 
 * @param i 要获取第几条记录 
 * @return MysqlRecord类型的数据，可以根据字段获取相关信息，
 */
 MysqlRecord operator[](size_t i);

 protected:
 vector<map<string, string> > _data;
 };

 /**
 * @brief Query Record. 
 * 
 * @param sSql sql语句
 * @throws MysqlHelper_Exception
 * @return MysqlData类型的数据，可以根据字段获取相关信息
 */
 MysqlData queryRecord(const string& sSql);

 /**
 * @brief 定义字段类型， 
 * DB_INT:数字类型 
 * DB_STR:字符串类型
 */
 enum FT
 {
 DB_INT, 
 DB_STR, 
 };

 /**
 * 数据记录
 */
 typedef map<string, pair<FT, string> > RECORD_DATA;

 /**
 * @brief 更新记录. 
 * 
 * @param sTableName 表名
 * @param mpColumns 列名/值对
 * @param sCondition where子语句,例如:where A = B
 * @throws MysqlHelper_Exception
 * @return size_t 影响的行数
 */
 size_t updateRecord(const string &sTableName, const map<string, pair<FT, string> > &mpColumns, const string &sCondition);

 /**
 * @brief 插入记录. 
 * 
 * @param sTableName 表名
 * @param mpColumns 列名/值对
 * @throws MysqlHelper_Exception
 * @return size_t 影响的行数
 */
 size_t insertRecord(const string &sTableName, const map<string, pair<FT, string> > &mpColumns);

 /**
 * @brief 替换记录. 
 * 
 * @param sTableName 表名
 * @param mpColumns 列名/值对
 * @throws MysqlHelper_Exception
 * @return size_t 影响的行数
 */
 size_t replaceRecord(const string &sTableName, const map<string, pair<FT, string> > &mpColumns);

 /**
 * @brief 删除记录. 
 * 
 * @param sTableName 表名
 * @param sCondition where子语句,例如:where A = B
 * @throws MysqlHelper_Exception
 * @return size_t 影响的行数
 */
 size_t deleteRecord(const string &sTableName, const string &sCondition = "");

 /**
 * @brief 获取Table查询结果的数目. 
 * 
 * @param sTableName 用于查询的表名
 * @param sCondition where子语句,例如:where A = B
 * @throws MysqlHelper_Exception
 * @return size_t 查询的记录数目
 */
 size_t getRecordCount(const string& sTableName, const string &sCondition = "");

 /**
 * @brief 获取Sql返回结果集的个数. 
 * 
 * @param sCondition where子语句,例如:where A = B
 * @throws MysqlHelper_Exception
 * @return 查询的记录数目
 */
 size_t getSqlCount(const string &sCondition = "");

 /**
 * @brief 存在记录. 
 * 
 * @param sql sql语句
 * @throws MysqlHelper_Exception
 * @return 操作是否成功
 */
 bool existRecord(const string& sql);

 /**
 * @brief 获取字段最大值. 
 * 
 * @param sTableName 用于查询的表名
 * @param sFieldName 用于查询的字段
 * @param sCondition where子语句,例如:where A = B
 * @throws MysqlHelper_Exception
 * @return 查询的记录数目
 */
 int getMaxValue(const string& sTableName, const string& sFieldName, const string &sCondition = "");

 /**
 * @brief 获取auto_increment最后插入得ID. 
 * 
 * @return ID值
 */
 long lastInsertID();

 /**
 * @brief 构造Insert-SQL语句. 
 * 
 * @param sTableName 表名
 * @param mpColumns 列名/值对
 * @return string insert-SQL语句
 */
 string buildInsertSQL(const string &sTableName, const map<string, pair<FT, string> > &mpColumns);

 /**
 * @brief 构造Replace-SQL语句. 
 * 
 * @param sTableName 表名
 * @param mpColumns 列名/值对
 * @return string insert-SQL语句
 */
 string buildReplaceSQL(const string &sTableName, const map<string, pair<FT, string> > &mpColumns);

 /**
 * @brief 构造Update-SQL语句. 
 * 
 * @param sTableName 表名
 * @param mpColumns 列名/值对
 * @param sCondition where子语句
 * @return string Update-SQL语句
 */
 string buildUpdateSQL(const string &sTableName,const map<string, pair<FT, string> > &mpColumns, const string &sCondition);

 /**
 * @brief 获取最后执行的SQL语句.
 * 
 * @return SQL语句
 */
 string getLastSQL() { return _sLastSql; }

 /**
 * @brief 获取查询影响数
 * @return int
 */
 size_t getAffectedRows();
protected:
 /**
 * @brief copy contructor，只申明,不定义,保证不被使用 
 */
 MysqlHelper(const MysqlHelper &tcMysql);

 /**
 * 
 * @brief 只申明,不定义,保证不被使用
 */
 MysqlHelper &operator=(const MysqlHelper &tcMysql);


private:

 /**
 * 数据库指针
 */
 MYSQL *_pstMql;

 /**
 * 数据库配置
 */
 DBConf _dbConf;

 /**
 * 是否已经连接
 */
 bool _bConnected;

 /**
 * 最后执行的sql
 */
 string _sLastSql;

};
}
#endif //__MYSQL_HELPER_H__

//mysqlhelper.cpp

#include "mysqlHelper.h"

#include <string.h>
#include <sstream>

using namespace std;

namespace mysqlhelper{

MysqlHelper::MysqlHelper():_bConnected(false)
{
 _pstMql = mysql_init(NULL);
}

MysqlHelper::MysqlHelper(const string& sHost, const string& sUser, const string& sPasswd, const string& sDatabase, const string &sCharSet, int port, int iFlag)
:_bConnected(false)
{
 init(sHost, sUser, sPasswd, sDatabase, sCharSet, port, iFlag);

 _pstMql = mysql_init(NULL);
}

MysqlHelper::MysqlHelper(const DBConf& tcDBConf)
:_bConnected(false)
{
 _dbConf = tcDBConf;

 _pstMql = mysql_init(NULL); 
}

MysqlHelper::~MysqlHelper()
{
 if (_pstMql != NULL)
 {
 mysql_close(_pstMql);
 _pstMql = NULL;
 }
}

void MysqlHelper::init(const string& sHost, const string& sUser, const string& sPasswd, const string& sDatabase, const string &sCharSet, int port, int iFlag)
{
 _dbConf._host = sHost;
 _dbConf._user = sUser;
 _dbConf._password = sPasswd;
 _dbConf._database = sDatabase;
 _dbConf._charset = sCharSet;
 _dbConf._port = port;
 _dbConf._flag = iFlag;
}

void MysqlHelper::init(const DBConf& tcDBConf)
{
 _dbConf = tcDBConf;
}

void MysqlHelper::connect()
{
 disconnect();

 if( _pstMql == NULL)
 {
 _pstMql = mysql_init(NULL);
 }

 //建立连接后, 自动调用设置字符集语句
 if(!_dbConf._charset.empty()) {
 if (mysql_options(_pstMql, MYSQL_SET_CHARSET_NAME, _dbConf._charset.c_str())) {
 throw MysqlHelper_Exception(string("MysqlHelper::connect: mysql_options MYSQL_SET_CHARSET_NAME ") + _dbConf._charset + ":" + string(mysql_error(_pstMql)));
 }
 }

 if (mysql_real_connect(_pstMql, _dbConf._host.c_str(), _dbConf._user.c_str(), _dbConf._password.c_str(), _dbConf._database.c_str(), _dbConf._port, NULL, _dbConf._flag) == NULL) 
 {
 throw MysqlHelper_Exception("[MysqlHelper::connect]: mysql_real_connect: " + string(mysql_error(_pstMql)));
 }

 _bConnected = true;
}

void MysqlHelper::disconnect()
{
 if (_pstMql != NULL)
 {
 mysql_close(_pstMql);
 _pstMql = mysql_init(NULL);
 }

 _bConnected = false; 
}

string MysqlHelper::escapeString(const string& sFrom)
{
 if(!_bConnected)
 {
 connect();
 }

 string sTo;
 string::size_type iLen = sFrom.length() * 2 + 1;
 char *pTo = (char *)malloc(iLen);

 memset(pTo, 0x00, iLen);

 mysql_real_escape_string(_pstMql, pTo, sFrom.c_str(), sFrom.length());

 sTo = pTo;

 free(pTo);

 return sTo;
}

MYSQL *MysqlHelper::getMysql(void)
{
 return _pstMql;
}

string MysqlHelper::buildInsertSQL(const string &sTableName, const RECORD_DATA &mpColumns)
{
 ostringstream sColumnNames;
 ostringstream sColumnValues;

 map<string, pair<FT, string> >::const_iterator itEnd = mpColumns.end();

 for(map<string, pair<FT, string> >::const_iterator it = mpColumns.begin(); it != itEnd; ++it)
 {
 if (it == mpColumns.begin())
 {
 sColumnNames << "`" << it->first << "`";
 if(it->second.first == DB_INT)
 {
 sColumnValues << it->second.second;
 }
 else
 {
 sColumnValues << "'" << escapeString(it->second.second) << "'";
 }
 }
 else
 {
 sColumnNames << ",`" << it->first << "`";
 if(it->second.first == DB_INT)
 {
 sColumnValues << "," + it->second.second;
 }
 else
 {
 sColumnValues << ",'" + escapeString(it->second.second) << "'";
 }
 }
 }

 ostringstream os;
 os << "insert into " << sTableName << " (" << sColumnNames.str() << ") values (" << sColumnValues.str() << ")";
 return os.str();
}

string MysqlHelper::buildReplaceSQL(const string &sTableName, const RECORD_DATA &mpColumns)
{
 ostringstream sColumnNames;
 ostringstream sColumnValues;

 map<string, pair<FT, string> >::const_iterator itEnd = mpColumns.end();
 for(map<string, pair<FT, string> >::const_iterator it = mpColumns.begin(); it != itEnd; ++it)
 {
 if (it == mpColumns.begin())
 {
 sColumnNames << "`" << it->first << "`";
 if(it->second.first == DB_INT)
 {
 sColumnValues << it->second.second;
 }
 else
 {
 sColumnValues << "'" << escapeString(it->second.second) << "'";
 }
 }
 else
 {
 sColumnNames << ",`" << it->first << "`";
 if(it->second.first == DB_INT)
 {
 sColumnValues << "," + it->second.second;
 }
 else
 {
 sColumnValues << ",'" << escapeString(it->second.second) << "'";
 }
 }
 }

 ostringstream os;
 os << "replace into " << sTableName << " (" << sColumnNames.str() << ") values (" << sColumnValues.str() << ")";
 return os.str();
}

string MysqlHelper::buildUpdateSQL(const string &sTableName,const RECORD_DATA &mpColumns, const string &sWhereFilter)
{
 ostringstream sColumnNameValueSet;

 map<string, pair<FT, string> >::const_iterator itEnd = mpColumns.end();

 for(map<string, pair<FT, string> >::const_iterator it = mpColumns.begin(); it != itEnd; ++it)
 {
 if (it == mpColumns.begin())
 {
 sColumnNameValueSet << "`" << it->first << "`";
 }
 else
 {
 sColumnNameValueSet << ",`" << it->first << "`";
 }

 if(it->second.first == DB_INT)
 {
 sColumnNameValueSet << "= " << it->second.second;
 }
 else
 {
 sColumnNameValueSet << "= '" << escapeString(it->second.second) << "'";
 }
 }

 ostringstream os;
 os << "update " << sTableName << " set " << sColumnNameValueSet.str() << " " << sWhereFilter;

 return os.str();
}

string MysqlHelper::getVariables(const string &sName)
{
 string sql = "SHOW VARIABLES LIKE '" + sName + "'";

 MysqlData data = queryRecord(sql);
 if(data.size() == 0)
 {
 return "";
 }

 if(sName == data[0]["Variable_name"])
 {
 return data[0]["Value"];
 }

 return "";
}

void MysqlHelper::execute(const string& sSql)
{
 /**
 没有连上, 连接数据库
 */
 if(!_bConnected)
 {
 connect();
 }

 _sLastSql = sSql;

 int iRet = mysql_real_query(_pstMql, sSql.c_str(), sSql.length());
 if(iRet != 0)
 {
 /**
 自动重新连接
 */
 int iErrno = mysql_errno(_pstMql);
 if (iErrno == 2013 || iErrno == 2006)
 {
 connect();
 iRet = mysql_real_query(_pstMql, sSql.c_str(), sSql.length());
 }
 }

 if (iRet != 0)
 {
 throw MysqlHelper_Exception("[MysqlHelper::execute]: mysql_query: [ " + sSql+" ] :" + string(mysql_error(_pstMql))); 
 }
}

MysqlHelper::MysqlData MysqlHelper::queryRecord(const string& sSql)
{
 MysqlData data;

 /**
 没有连上, 连接数据库
 */
 if(!_bConnected)
 {
 connect();
 }

 _sLastSql = sSql;

 int iRet = mysql_real_query(_pstMql, sSql.c_str(), sSql.length());
 if(iRet != 0)
 {
 /**
 自动重新连接
 */
 int iErrno = mysql_errno(_pstMql);
 if (iErrno == 2013 || iErrno == 2006)
 {
 connect();
 iRet = mysql_real_query(_pstMql, sSql.c_str(), sSql.length());
 }
 }

 if (iRet != 0)
 {
 throw MysqlHelper_Exception("[MysqlHelper::execute]: mysql_query: [ " + sSql+" ] :" + string(mysql_error(_pstMql))); 
 }

 MYSQL_RES *pstRes = mysql_store_result(_pstMql);

 if(pstRes == NULL)
 {
 throw MysqlHelper_Exception("[MysqlHelper::queryRecord]: mysql_store_result: " + sSql + " : " + string(mysql_error(_pstMql)));
 }

 vector<string> vtFields;
 MYSQL_FIELD *field;
 while((field = mysql_fetch_field(pstRes)))
 {
 vtFields.push_back(field->name);
 }

 map<string, string> mpRow;
 MYSQL_ROW stRow;

 while((stRow = mysql_fetch_row(pstRes)) != (MYSQL_ROW)NULL)
 {
 mpRow.clear();
 unsigned long * lengths = mysql_fetch_lengths(pstRes);
 for(size_t i = 0; i < vtFields.size(); i++)
 {
 if(stRow[i])
 {
 mpRow[vtFields[i]] = string(stRow[i], lengths[i]);
 }
 else
 {
 mpRow[vtFields[i]] = "";
 }
 }

 data.data().push_back(mpRow);
 }

 mysql_free_result(pstRes);

 return data;
}

size_t MysqlHelper::updateRecord(const string &sTableName, const RECORD_DATA &mpColumns, const string &sCondition)
{
 string sSql = buildUpdateSQL(sTableName, mpColumns, sCondition);
 execute(sSql);

 return mysql_affected_rows(_pstMql);
}

size_t MysqlHelper::insertRecord(const string &sTableName, const RECORD_DATA &mpColumns)
{
 string sSql = buildInsertSQL(sTableName, mpColumns);
 execute(sSql);

 return mysql_affected_rows(_pstMql);
}

size_t MysqlHelper::replaceRecord(const string &sTableName, const RECORD_DATA &mpColumns)
{
 string sSql = buildReplaceSQL(sTableName, mpColumns);
 execute(sSql);

 return mysql_affected_rows(_pstMql);
}

size_t MysqlHelper::deleteRecord(const string &sTableName, const string &sCondition)
{
 ostringstream sSql;
 sSql << "delete from " << sTableName << " " << sCondition;

 execute(sSql.str());

 return mysql_affected_rows(_pstMql);
}

size_t MysqlHelper::getRecordCount(const string& sTableName, const string &sCondition)
{
 ostringstream sSql;
 sSql << "select count(*) as num from " << sTableName << " " << sCondition;

 MysqlData data = queryRecord(sSql.str());

 long n = atol(data[0]["num"].c_str());

 return n;

}

size_t MysqlHelper::getSqlCount(const string &sCondition)
{
 ostringstream sSql;
 sSql << "select count(*) as num " << sCondition;

 MysqlData data = queryRecord(sSql.str());

 long n = atol(data[0]["num"].c_str());

 return n;
}

int MysqlHelper::getMaxValue(const string& sTableName, const string& sFieldName,const string &sCondition)
{
 ostringstream sSql;
 sSql << "select " << sFieldName << " as f from " << sTableName << " " << sCondition << " order by f desc limit 1";

 MysqlData data = queryRecord(sSql.str());

 int n = 0;

 if(data.size() == 0)
 {
 n = 0;
 }
 else
 {
 n = atol(data[0]["f"].c_str());
 }

 return n;
}

bool MysqlHelper::existRecord(const string& sql)
{
 return queryRecord(sql).size() > 0;
}

long MysqlHelper::lastInsertID()
{
 return mysql_insert_id(_pstMql);
}

size_t MysqlHelper::getAffectedRows()
{
 return mysql_affected_rows(_pstMql);
}

//////////////////////////////////////////////////////////////////////////////////////////////////////////////
MysqlHelper::MysqlRecord::MysqlRecord(const map<string, string> &record):_record(record){}

const string& MysqlHelper::MysqlRecord::operator[](const string &s)
{
 map<string, string>::const_iterator it = _record.find(s);
 if(it == _record.end())
 {
 throw MysqlHelper_Exception("field '" + s + "' not exists.");
 }
 return it->second;
}

//////////////////////////////////////////////////////////////////////////////////////////////////////////////

vector<map<string, string> >& MysqlHelper::MysqlData::data()
{
 return _data;
}

size_t MysqlHelper::MysqlData::size()
{
 return _data.size();
}

MysqlHelper::MysqlRecord MysqlHelper::MysqlData::operator[](size_t i)
{
 return MysqlRecord(_data[i]);
}

}//end namespace 

/****************************************************
*@brief:mysqlhelper demo
*@autor:lvlv
*@date:2016.06.12
*@MySQL version:MySQL Community Server 5.6.30 (GPL)
****************************************************/

#include <string.h>
#include <iostream>
#include <string>
using namespace std;

#include "mysqlHelper.h"
using namespace mysqlhelper;


int main(int argc,char* argv[]){

 //初始化mysql对象并建立连接
 MysqlHelper mysqlHelper;
 mysqlHelper.init("119.29.184.114","root","123456","StudentCourse");
 try{
 mysqlHelper.connect();
 }catch(MysqlHelper_Exception& excep){
 cout<<excep.errorInfo;
 return -1;
 }

 //增加一条学生记录
 //示例插入语句
 //string sql="insert into student values("201421031060","吕吕","华南理工大学","2014","软件工程",1)";

 MysqlHelper::RECORD_DATA record;
 record.insert(make_pair("studentNo",make_pair(MysqlHelper::DB_STR,"201421031060")));
 record.insert(make_pair("name",make_pair(MysqlHelper::DB_STR,"吕吕")));
 record.insert(make_pair("school",make_pair(MysqlHelper::DB_STR,"广州中医药大学")));
 record.insert(make_pair("grade",make_pair(MysqlHelper::DB_STR,"2014")));
 record.insert(make_pair("major",make_pair(MysqlHelper::DB_STR,"计算机科学与技术")));
 record.insert(make_pair("gender",make_pair(MysqlHelper::DB_INT,"1")));
 int res=0;
 try{
 res=mysqlHelper.insertRecord("student",record);
 }catch(MysqlHelper_Exception& excep){
 cout<<excep.errorInfo;
 return -1;
 }
 cout<<"res:"<<res<<" insert successfully "<<endl;

 //删除一条学生记录，学号为201421031059
 try{
 res=mysqlHelper.deleteRecord("student","where studentNo=\"201421031059\"");
 }catch(MysqlHelper_Exception& excep){
 cout<<excep.errorInfo;
 return -1;
 }
 cout<<"res:"<<res<<" delete successfully "<<endl;

 //查找学号为201421031059的学生选择的所有课程名称
 MysqlHelper::MysqlData dataSet;
 string querySQL="select courseName from course co where co.courseNo in (select courseNo from courseSelection where studentNo=\"201421031060\")";
 try{
 dataSet=mysqlHelper.queryRecord(querySQL);
 }catch(MysqlHelper_Exception& excep){
 cout<<excep.errorInfo;
 return -1;
 }
 cout<<"query successfully"<<endl;
 for(size_t i=0;i<dataSet.size();++i){
 cout<<dataSet[i]["courseName"]<<endl;
 }

 //修改学号为201421031060的学生专业
 MysqlHelper::RECORD_DATA recordChange;
 recordChange.insert(make_pair("major",make_pair(MysqlHelper::DB_STR,"软件工程")));
 try{
 res=mysqlHelper.updateRecord("student",recordChange,"where studentNo=\"201421031060\"");
 }catch(MysqlHelper_Exception& excep){
 cout<<excep.errorInfo;
 return -1;
 }
 cout<<"res:"<<res<<" update successfully"<<endl;

 return 0;
}

##################################
# @brief:make scripts
# @date:2016.05.28
# @author:lvlv
##################################

#environment var
VPATH+=.

CC:=g++
FLAGS=-g -Wall -std=c++11
INC+=-I/usr/local/mysql/include
LIBDIR+=-L/usr/local/mysql/lib

CPPDIRS=.
CPPS=$(shell for dir in ${CPPDIRS};do echo $${dir}/*.cpp;done)

OBJDIR=obj
OBJS=$(patsubst %.cpp,${OBJDIR}/%.o,$(notdir ${CPPS}))

TARGET:=mysqlDemo.out

${TARGET}:${OBJS}
 ${CC} ${FLAGS} ${OBJS} -o $@ ${LIBDIR} -lmysqlclient

${OBJDIR}/%.o:./%.cpp
 ${CC} ${FLAGS} ${INC} -o $@ -c $<

.PHONY:clean
clean:
 rm -f ${TARGET} ${OBJDIR}/*