poco数据库访问MySql：

a.  创建会话(session)

b. 从DB中读写数据

c. 使用statements

d. 使用容器（Collection） (数据，集合...)
e. 使用limit限定

f. 如何使用复杂的数据类型(如何将一个C++对象映射到数据库的表

创建会话：Session create(const std::string& connectorKey, const std::string& connectionString);
参数1：SQLite；MySQL；或者ODBC，ODBC支持Oracle, SQLite, DB2, SQLServer和PostgreSQL。
参数2：就是数据库文件的路径或者连接字符

基本操作（增删查改）：

增：

	std::string aName("Peter");
	ses << "INSERT INTO 表名 VALUES(" << aName << ")", now;
	或者ses << "INSERT INTO 表名 VALUES(?)", use(aName), now;

查：

一般查找

	std::string aName;
	ses << "SELECT NAME FROM FORENAME", into(aName), now; // aName的默认值为空字符串
	ses << "SELECT NAME FROM FORENAME", into(aName, "default"), now;

匹配查找  先into后use  且不能使用常量 如:4

	std::string aName;
	std::string match("Peter")
	ses << "SELECT NAME FROM FORENAME WHERE NAME=?", into(aName), use(match), now;
	poco_assert (aName == match);

多字节匹配查找

	std::string firstName("Peter";
	std::string lastName("Junior");
	int age = 0;
	ses << "INSERT INTO PERSON VALUES (?, ?, ?)", use(firstName), use(lastName), use(age), now;
	ses << "SELECT (firstname, lastname, age) FROM Person", into(firstName), into(lastName), into(age), now;

into语句允许定义一个默认值,主要针对数据库查询里面包含空时候

	ses << "SELECT (firstname, lastname, age) FROM Person", into(firstName), into(lastName), into(age, -1), now;

改：
	session << "update Person set Address = ? WHERE Name= ?", use(addr),use(name),now;

使用Statements：

用于保存SQl语句，使得多次查询。

	std::string aName("Peter");
	Statement stmt = ( ses << "INSERT INTO FORENAME VALUES(?)", use(aName) );//括号必须

或者

	Statement stmt(ses);
	stmt << "INSERT INTO FORENAME VALUES(?)", use(aName);

eg：

	std::string aName("Peter");
	Statement stmt = ( ses << "INSERT INTO FORENAME VALUES(?)", use(aName) );
	.
	.
	stmt.execute();
	poco_assert (stmt.done());

容器使用：

默认支持以下容器类：
a. vector(数组): 无特别要求
b. set: 类型需要支持<操作符，注意：重复的key/value将忽略
c.  multiset: 需支持<操作符
d. map: 需支持()操作符，并且按key返回对象，注意：重复的key/value将忽略
e. multimap: 需支持()操作符，并按key返加对象.

		std::vector<std::string> names;
		ses << "SELECT NAME FROM FORENAME", into(names), now;

Limit限定：针对查询结果的个数限定

		std::vector<std::string> names;
		ses << "SELECT NAME FROM FORENAME", into(names), limit(50), now;

以上代码将只返回50行的数据。（当然也可能什么都不返回）,并追加到 names这个容量中。如果想确保50行记录返回，需要设置limit的第二参数为true(默认为false):

		std::vector<std::string> names;
		ses << "SELECT NAME FROM FORENAME", into(names), limit(50, true), now;
		Statement stmt = (ses << "SELECT NAME FROM FORENAME", into(aName), lowerLimit(1), upperLimit(10));//限制范围
		Statement stmt = (ses << "SELECT NAME FROM FORENAME", into(aName), range(1,10));

类作为保存变量：这个就是将自定义类作为容器查询

		namespace Poco 
		{
			namespace Data
				 {
					template <>
					class TypeHandler<class Person>
						{
							.....
						}
				}
		}

记录集(RecordSet)

a. 遍历数据表中所有的行与列
b. 获取各列的元信息，比如名称，类型，长度等.

			Statement select(session);
			select << "SELECT * FROM Person";
			select.execute();
			RecordSet rs(select);

遍历结果：

			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();
			}

Tuples：在数据库中的列类型已知的情阅下，Poco::Tuple以及Tuple数组提供了更简便的方法获取数据。

			typedef Poco::Tuple<std::string, std::string, int> Person;
			typedef std::vector<Person> People;

			People people;
			people.push_back(Person("Bart Simpson", "Springfield", 12));
			people.push_back(Person("Lisa Simpson", "Springfield", 10));

			Statement insert(session);
			insert << "INSERT INTO Person VALUES(?, ?, ?)",
			use(people), now;

			当然，tuple也可以用于查询:
			Statement select(session);
			select << "SELECT Name, Address, Age FROM Person", into(people),  now;

			for (People::const_iterator it = people.begin(); it != people.end(); ++it)
			{
				std::cout << "Name: " << it->get<0>() <<
				", Address: " << it->get<1>() <<
				", Age: " << it->get<2>() <<std::endl;
			}

参考链接： http://pocoproject.org/docs/00200-DataUserManual.html

 测试代码：

#include "Poco/Data/Session.h"
#include "Poco/Data/MySQL/Connector.h"
#include <vector>
#include <iostream>


using namespace Poco::Data::Keywords;
using Poco::Data::Session;
using Poco::Data::Statement;


struct Person
{
	std::string name;
	std::string address;
	int         age;
};


int main(int argc, char** argv)
{
	Poco::Data::MySQL::Connector::registerConnector();

	// 创建 session
	Session session("MySQL", "host=127.0.0.1;port=3306;db=demo;user=admin;password=admin;compress=true;auto-reconnect=true");

	// 删除已存在的表
	session << "DROP TABLE IF EXISTS Person", now;

	// 创建新表
	session << "CREATE TABLE Person (Name char(20),Address char(30) ,Age integer)", now;//varchar 会报错
	// 插入数据
	Person person =
	{
		"Bart Simpson",
		"Springfield",
		12
	};

	Statement insert(session);
	insert << "INSERT INTO Person VALUES(?, ?, ?)",
		use(person.name),
		use(person.address),
		use(person.age);

	insert.execute();

	person.name = "Lisa Simpson";
	person.address = "Springfield";
	person.age = 10;

	insert.execute();

	//查询数据
	Statement select(session);
	select << "select Name, Address, Age FROM Person",
		into(person.name),
		into(person.address),
		into(person.age),
		range(0, 1); //  只查询前两行


	while (!select.done())
	{
		select.execute();
		std::cout << person.name << " " << person.address << " " << person.age << std::endl;
	}

	std::string addr = "hubeilichuan";
	std::string name = "Lisa Simpson";

	session << "update Person set Address = ? WHERE Name= ?", use(addr),use(name),now;
	// 另一种查询方式
	std::vector<std::string> names;
	session << "SELECT Address FROM Person",
		into(names),
		now;


	for (std::vector<std::string>::const_iterator it = names.begin(); it != names.end(); ++it)
	{
		std::cout << *it << std::endl;
	}
	getchar();
	return 0;
}

测试工程链接：http://download.csdn.net/detail/hl2015222050145/9614574

编译好的动态库链接：http://download.csdn.net/detail/hl2015222050145/9614205