MySQL-C ++ wrapper class

Reference: https://blog.csdn.net/daoming1112/article/details/54710743

 

MySQLInterface.h：

 

// MySQLInterface

// Function Description: encapsulate the realization of access operations MySQL

#ifndef __MYSQL_INTERFACE_H__
#define __MYSQL_INTERFACE_H__

#include <string>
#include <vector>

# The include <winsock.h> // Remote Access
#include "MySQL/include/mysql.h"

// imports related libraries
#pragma comment(lib, "ws2_32.lib")
#pragma comment(lib, "MySQL/lib/libmysql.lib")

# The DEFINE ERROR_QUERY_FAIL -1 // operation fails


// define the MySQL connection information
typedef struct
{
char* server;
char* user;
char* password;
char* database;
int port;
}MySQLConInfo;

class MySQLInterface
{
public:
MySQLInterface();
virtual ~MySQLInterface();

void SetMySQLConInfo ( char * Server, char * username, char * password, char * Database, int Port) ; // set the connection information
BOOL the Open () ; // open connection
void the Close () ; // close the connection

bool Select(const std::string& Querystr, std::vector<std::vector<std::string> >& data); // 读取数据
BOOL Query ( const STD :: String & queryStr) ; // else
int GetInsertID ( const std :: String & queryStr) ; // get inserted and the insertion of ID, for auto-increment ID
void ErrorIntoMySQL () ; // Error Messages

public:
int ErrorNum; // error code
const char * ErrorInfo; // error

private:
MysqlConInfo MySQLConInfo; // Connection Information
MysqlInstance MYSQL; // MySQL objects
* The Result MYSQL_RES; // for the result
};

#endif

MySQLInterface.cpp:

 

#include "stdafx.h"
#include "MySQLInterface.h"


MySQLInterface::MySQLInterface() :
ErrorNum( 0), ErrorInfo( "ok")
{
mysql_library_init( 0, NULL, NULL);
mysql_init(&MysqlInstance);

// set the character set, or can not handle Chinese
mysql_options(&MysqlInstance, MYSQL_SET_CHARSET_NAME, "gbk");
}

MySQLInterface::~MySQLInterface()
{
}

// set the connection information
void MySQLInterface::SetMySQLConInfo( char* server, char* username, char* password, char* database, int port)
{
MysqlConInfo.server = server;
MysqlConInfo.user = username;
MysqlConInfo.password = password;
MysqlConInfo.database = database;
MysqlConInfo.port = port;
}

// open connection
bool MySQLInterface::Open()
{
if (mysql_real_connect(&MysqlInstance, MysqlConInfo.server, MysqlConInfo.user,
MysqlConInfo.password, MysqlConInfo.database, MysqlConInfo.port, 0, 0) != NULL)
{
return true;
}
else
{
ErrorIntoMySQL ();
return false;
}
}

// Disconnect
void MySQLInterface::Close()
{
mysql_close(&MysqlInstance);
}

// read data
bool MySQLInterface::Select( const std:: string& Querystr, std:: vector< std:: vector< std:: string> >& data)
{
if ( 0 != mysql_query(&MysqlInstance, Querystr.c_str()))
{
ErrorIntoMySQL ();
return false;
}

Result = mysql_store_result(&MysqlInstance);

// ranks number
int row = mysql_num_rows(Result);
int field = mysql_num_fields(Result);

MYSQL_ROW line = NULL;
line = mysql_fetch_row(Result);

int j = 0;
std:: string temp;
std:: vector< std:: vector< std:: string> >().swap(data);
while ( NULL != line)
{
std:: vector< std:: string> linedata;
for ( int i = 0; i < field; i++)
{
if (line[i])
{
temp = line[i];
linedata.push_back(temp);
}
else
{
temp = "";
linedata.push_back(temp);
}
}
line = mysql_fetch_row(Result);
data.push_back(linedata);
}
return true;
}

// other operations
bool MySQLInterface::Query( const std:: string& Querystr)
{
if ( 0 == mysql_query(&MysqlInstance, Querystr.c_str()))
{
return true ;
}
ErrorIntoMySQL ();
return false;
}

// insert and get inserted ID, for auto-increment ID
int MySQLInterface::GetInsertID( const std:: string& Querystr)
{
if (!Query(Querystr))
{
ErrorIntoMySQL ();
return ERROR_QUERY_FAIL;
}
// Get ID
return mysql_insert_id(&MysqlInstance);
}

// error message
void MySQLInterface::ErrorIntoMySQL()
{
ErrorNum = mysql_errno(&MysqlInstance);
ErrorInfo = mysql_error(&MysqlInstance);
}

Example

#include <iostream> using namespace std;   #include "MySQLInterface.h"    int _tmain(int argc, _TCHAR* argv[]) {          MySQLInterface MySQLInterface;          MySQLInterface.SetMySQLConInfo("localhost", "root", "123456", "world", 337);          if (!MySQLInterface.Open())          {                   std::cout << MySQLInterface.ErrorNum << " : " << MySQLInterface.ErrorInfo << std::endl;          }            // read data          std::vector<std::vector<std::string> > data;          std::string sqlstr = "SELECT `ID`,`Name`,`CountryCode`,`District` FROM `world`.`city` LIMIT 10";          MySQLInterface.Select(sqlstr, data);            // Display Data          for (unsigned int i = 0; i < data.size(); ++i)          {                   for (unsigned int j = 0; j < data[0].size(); ++j)                   {                           cout << data[i][j] << "\t\t";                   }                   cout << endl;          }            // 其他操作          sqlstr = "CREATE TABLE IF NOT EXISTS `new_paper` (";          sqlstr += " `NewID` int(11) NOT NULL AUTO_INCREMENT,";          sqlstr += " `NewCaption` varchar(40) NOT NULL,";          sqlstr += " `NewContent` text,";          sqlstr += " `NewTime` datetime DEFAULT NULL,";          sqlstr += " PRIMARY KEY(`NewID`)";          sqlstr += " ) ENGINE = InnoDB DEFAULT CHARSET = utf8";            if (!MySQLInterface.Query(sqlstr))          {                   std::cout << MySQLInterface.ErrorNum << " : " << MySQLInterface.ErrorInfo << std::endl;          }            MySQLInterface.Close();            system("pause");          return 0; }

 

 

错误提示

MFC (CString)

if (!m_MySQLInter.Open()) // 连接失败     {          CString strError = _T("");          USES_CONVERSION;          strError.Format(_T("打开数据库失败...\n%d : %s"), m_MySQLInter.ErrorNum, A2W(m_MySQLInter.ErrorInfo));          ::MessageBox(GetSafeHwnd(), strError, _T("系统提示"), MB_ICONEXCLAMATION | MB_OK);          return;     }

 

Win32

         if(!m_MySQLInter.Open())

         {

                  std::cout<< m_MySQLInter.ErrorNum << " : " <<m_MySQLInter.ErrorInfo << std::endl;

                  return;

         }

 

 

类型转换

Std::string to char*

// 类型转换          char* pDatabase = new char[strlen(database.c_str()) + 1];          strcpy(pDatabase, database.c_str());          char* pPassword = new char[strlen(password.c_str()) + 1];          strcpy(pPassword, password.c_str());          char* pUserName = new char[strlen(usename.c_str()) + 1];          strcpy(pUserName, usename.c_str());          char* pServer = new char[strlen(server.c_str()) + 1];          strcpy(pServer, server.c_str());            m_MySQLInter.SetMySQLConInfo(pServer, pUserName, pPassword, pDatabase, port);

 

CString to char*

USES_CONVERSION;     m_MySQLInter.SetMySQLConInfo(W2A(m_strServer), W2A(m_strUserName), W2A(m_strPassword), "log", _ttoi(m_strPort));       if (!m_MySQLInter.Open()) // 连接失败     {          CString strError = _T("");          USES_CONVERSION;          strError.Format(_T("打开数据库失败...\n%d : %s"), m_MySQLInter.ErrorNum, A2W(m_MySQLInter.ErrorInfo));          ::MessageBox(GetSafeHwnd(), strError, _T("系统提示"), MB_ICONEXCLAMATION | MB_OK);          return;     }