c++ 简单封装mysql数据库连接类 实例
在c++开发过程中，我们可能会用到mysql数据库，这边我简单写了一个类似PHP封装的mysql类，希望能帮助像我这样的C++初学者。
首先我们要安装mysql c++ 库下载地址
http://dev.mysql.com/downloads/connector/cpp/
我的环境是centos5.5
安装完毕后 看代码：
#include "mysql_connection.h"
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
#include <stdlib.h>
#include <iostream>
using namespace std;
class mysql_database
{
private:
string db_host;
string db_name;
string db_user;
string db_passwd;
string db_charset;
string db_port;
sql::Driver *driver;
sql::Connection *con;
sql::Statement *stmt;
sql::ResultSet *result;
public:
mysql_database(map<string,string> &conf) :
driver(NULL),con(NULL),stmt(NULL),result(NULL)
{
db_host=conf["db_host"];
db_name=conf["db_name"];
db_user=conf["db_user"];
db_passwd=conf["db_passwd"];
db_port=conf["db_port"];
db_charset=conf["db_charset"];
}
sql::Connection *db_connect(string database="")
{
try{
string db;
db=(database=="")?db_name:database;
driver = get_driver_instance();
//cout<<db_host<<db_port<<db_user<<db_passwd<<db_name<<endl;
con = driver->connect("tcp://"+db_host+":"+db_port, db_user, db_passwd);
con->setSchema(db);
this->squery("SET NAMES "+db_charset);
return con;
}
catch (sql::SQLException &e)
{
cout << "# ERR: SQLException in " << __FILE__;
cout << "(" << __FUNCTION__ << ") on line "<< __LINE__ << endl;
cout << "# ERR: " << e.what();
cout << " (MySQL error code: " << e.getErrorCode();
cout << ", SQLState: " << e.getSQLState() << " )" << endl;
}
}
/**
* simple query for create/update/delete
* @param string sql
* @return bool TRUE OR FALS
*/
bool squery(string sql)
{
stmt = con->createStatement();
return stmt->execute(sql);
}
sql::ResultSet *query(string sql)
{
stmt = con->createStatement();
result=stmt->executeQuery(sql);
return result;
}
/* retrieve the row count in the result set */
int get_total(sql::ResultSet *result)
{
int total;
total=result->rowsCount();
return total;
}
/**
* fetch query rows
* @param result
* @param field the db table's field for this query
* @return mutil_map
*/
map<int,map<string,string> > fetch_map(sql::ResultSet *result,map<string,string>field)
{
/* fetch the data : retrieve all the rows in the result set */
map<int,map<string,string> > data;
map<string,string>::iterator it;
int k=0;
if((!field.empty())&&(field.size()>0))
{
while(result->next())
{
map<string,string> row;
for ( it=field.begin() ; it!=field.end() ;it++ )
row[it->first]=result->getString(it->second);
data[k]=row;
k++;
}
}
return data ;
}
};
用法如下：
#include<iostream>
#include<string>
#include<stdlib.h>
#include<map>
#include <boost/date_time.hpp>
#include "mysql_database.h"
#include "parase_ini.h"
using namespace boost;
using namespace std;
int main()
{
parase_ini conf("config.ini");
map<string,string> config=conf.get_config();
mysql_database db (config);
db.db_connect();
sql::ResultSet * rs;
map<string,string> field ;
field["0"]="v_name" ;//
rs=db.query("select v_name from pi_data limit 1 ");
map<int,map<string,string> > rows;
rows=db.fetch_map(rs,field);
map<int,map<string,string> >::iterator it;
for (it=rows.begin();it!=rows.end();it++)
{
map<string,string>::iterator item;
map<string,string> content;
content=it->second;
for (item=content.begin();item!=content.end();item++)
{
cout<<item->second<<endl;
}
}
//----------- db2 start -----------
db.db_connect("df17db");
field["0"]="username";
field["1"]="name";
rs=db.query("select * from zhuna_admin");
rows=db.fetch_map(rs,field);
for (it=rows.begin();it!=rows.end();it++)
{
map<string,string>::iterator item;
map<string,string> content;
content=it->second;
string str;
for (item=content.begin();item!=content.end();item++)
{
//cout<<item->second<<endl;
str+=item->second+"\t";
}
str+="\n";
cout<<str<<endl;
}
//------------ db2 end ---------------
}
说明 ：上面的用法可能有其他模块 ，同学们看数据库调用就行 了。