Mysql FEDERATED引擎

使用mysql federated引擎构建MySQL分布式数据库访问层：
http://zhangxugg-163-com.iteye.com/blog/1666673FEDERATED
Storage Engine Notes and Tips：http://dev.mysql.com/doc/refman/5.7/en/federated-usagenotes.html


Federated引擎是基于表级别的，只能将本地数据表定义为 Federated 引擎并映射至远程实体表，无法实现基于库级别的整体映射。

进入MYSQL命令行，查看FEDERATED引擎是否开启，默认是不开启

>show engines;
mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+-----+------------+
| Engine             | Support | Comment                                                        | Transactions | XA  | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+-----+------------+
| FEDERATED          | YES     | Federated MySQL storage engine                                 | NO           | NO  | NO         |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables                          | NO           | NO  | NO         |
| MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO  | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO  | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO  | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO  | NO         |
| ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO  | NO         |
| CSV                | YES     | CSV storage engine                                             | NO           | NO  | NO         |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES | YES        |
+--------------------+---------+----------------------------------------------------------------+--------------+-----+------------+
9 rows in set

如果没有开启，配置my.cnf

[mysqld]
feterated

重启
在远程机192.168.32.128上创建数据库log，创建表test，如下：

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for test
-- ----------------------------
DROP TABLE IF EXISTS `test`;
CREATE TABLE "test" (
  "id" int(11) NOT NULL AUTO_INCREMENT,
  "name" varchar(255) DEFAULT NULL,
  PRIMARY KEY ("id")
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ;

创建用户，授予权限

FLUSH PRIVILEGES;
CREATE USER 'donald'@'%' IDENTIFIED BY '123456';
GRANT ALL PRIVILEGES ON *.* TO 'donald'@'%' IDENTIFIED BY '123456';  
FLUSH PRIVILEGES;

在本地创建相应的表：

-- ----------------------------
-- Table structure for test
-- ----------------------------
DROP TABLE IF EXISTS `test`;
CREATE TABLE "test" (
  "id" int(11) NOT NULL AUTO_INCREMENT,
  "name" varchar(255) DEFAULT NULL,
  PRIMARY KEY ("id")
) ENGINE=FEDERATED CONNECTION='mysql://donald:123456@192.168.32.128:3306/log/test';

插入数据：

INSERT INTO `log`.`test` (`id`, `name`) VALUES ('1', 'donald');
INSERT INTO `log`.`test` (`id`, `name`) VALUES ('2', 'jamel');

查询数据：
mysql> use test;
Database changed
mysql> select * from test;
+----+--------+
| id | name   |
+----+--------+
|  1 | donald |
|  2 | jamel  |
+----+--------+