poco c++框架库应用:数据库的连接池
Poco c++中的数据库驱动部分,简洁,干净,工整,和数据库连接,封装成这样,还是比较好用的.下面是连接MySQL连接的方法.
一 需求说明
与MySQL数据库建立连接池,并在连接池中获得一个连接,实现数据库常用增删改查
二 目标说明
写出ANSI风格的代码,并输出高度结果到终端,验证程序的有效性
三 调试条件:
1.系统:ubuntu
2.qt 或 其它IDE
3.安装了mysql,有正确的访问账户和密码
四 例程说明
使用IDE:Qt Creator
项目文件:pocomysql.pro
QT += core network QT -= gui TARGET = poco_mysql CONFIG += console CONFIG -= app_bundle DEFINES += CHARTDIR_HIDE_OBSOLETE _CRT_SECURE_NO_WARNINGS INCLUDEPATH += /usr/local/include/Poco -I /usr/include/mysql LIBS += -L/usr/local/lib -lPocoData -lPocoDataMySQL -lPocoDataSQLite -lPocoCrypto -lPocoUtil -lPocoFoundation -L /usr/lib64/mysql #LIBS += -L/usr/local/lib -lPocoData -lPocoDataSQLite -lPocoFoundation -lPocoCrypto -lPocoUtil SOURCES += \ mysql.cpp
main文件
#include "Poco/String.h"
#include "Poco/Format.h"
#include "Poco/Exception.h"
#include "Poco/Data/StatementImpl.h"
#include "Poco/Data/MySQL/Connector.h"
#include "Poco/Data/MySQL/MySQLException.h"
#include "Poco/Data/Session.h"
#include "Poco/Data/SessionPool.h"
#include "Poco/Data/SessionFactory.h"
#include "Poco/Data/LOB.h"
#include "Poco/Data/MySQL/MySQLStatementImpl.h"
#include "Poco/DateTime.h"
#include "Poco/Data/RecordSet.h"
#include "Poco/Data/Column.h"
#include <iostream>
using namespace Poco::Data::Keywords;
using namespace Poco::Data;
using Poco::Data::Session;
using Poco::Data::MySQL::ConnectionException;
using Poco::Data::MySQL::StatementException;
using Poco::NotFoundException;
using Poco::Data::Statement;
using Poco::DateTime;
using Poco::Data::RecordSet;
//给出访问数据库的信息
std::string _dbConnString = "host=localhost;port=3306;"
"user=root;password=19810311;"
"db=smart;"
"compress=true;auto-reconnect=true";
int main(int argc, char** argv)
{
MySQL::Connector::registerConnector();
//与数据库建立一个连接池
Poco::Data::SessionPool pool(MySQL::Connector::KEY, _dbConnString,1,32,10);
//从数据库存连接池中获得一个数据库连接
Poco::Data::Session ses(pool.get());
//如果与数据库建立会话成功,输出连接信息
if(ses.isConnected())
std::cout << "*** Connected to " << '(' << _dbConnString << ')' << std::endl;
//如果有为名ddjj的表,先删除,方便下面调试
ses << "DROP TABLE IF EXISTS ddjj", now;
//把查询结果存储到容器中
std::vector<std::string> names;
ses << "show databases",into(names), now;
//输出查询结果,此处列出所有数据库名称
for (std::vector<std::string>::const_iterator it = names.begin(); it != names.end(); ++it)
{
std::cout << *it << std::endl;
}
// 建立一个表,名为ddjj,字段名:name,sex
ses << "create table ddjj(name VARCHAR(20),sex VARCHAR(20));", now;
//实现数据纪录的插入
DateTime bd(1980, 4, 1);
DateTime ld(1982, 5, 9);
ses << "INSERT INTO ddjj VALUES('Bart Simpson', ?)", use(bd), now;
ses << "INSERT INTO ddjj VALUES('Lisa Simpson', ?)", use(ld), now;
//实现查询的方法,并输出查询结果
std::vector<std::string> names1;
ses << "select * from ddjj where name like 'Bart Simpson' ",
into(names1),
now;
for (std::vector<std::string>::const_iterator it = names1.begin(); it != names1.end(); ++it)
{
std::cout << "*** tables: " << *it << std::endl;
}
Statement select(ses);
select << "SELECT * FROM ddjj";
select.execute();
//创建纪录集
RecordSet rs(select);
std::size_t cols = rs.columnCount();
//输出列名
for (std::size_t col = 0; col < cols; ++col)
{
std::cout << rs.columnName(col) << std::endl;
}
//输出所有查询到的结果
bool more = rs.moveFirst();
while (more)
{
for (std::size_t col = 0; col < cols; ++col)
{
std::cout << rs[col].convert<std::string>() << " ";
}
std::cout << std::endl;
more = rs.moveNext();
}
ses.close();
MySQL::Connector::unregisterConnector();
return 0;
}
四 输出结果
*** Connected to (host=localhost;port=3306;user=root;password=19810311;db=smart;compress=true;auto-reconnect=true)
information_schema
mysql
performance_schema
smart
*** tables: Bart Simpson
name
sex
Bart Simpson 1980-04-01 00:00:00
Lisa Simpson 1982-05-09 00:00:00