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;
	}
	
}

//------------------------------------------------------------------------------
// end

//------------------------------------------------------------------------------
// 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：