【MySQL】DB-Link 跨库访问
作者：互联网
相关说明：
https://blog.csdn.net/qq_48721706/article/details/124088963
DB-LINK以一个远程访问方式访问其他MYSQL实例
连接实例和被连接实例都需要开启FEDERATED引擎
Federated引擎配置
检查库是否支持FEDERATED
SHOW ENGINES; +--------------------+---------+----------------------------------------------------------------+--------------+------+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +--------------------+---------+----------------------------------------------------------------+--------------+------+------------+ | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO | | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO | | CSV | YES | CSV storage engine | NO | NO | NO | | FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL | | PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO | | MyISAM | YES | MyISAM storage engine | NO | NO | NO | | InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES | | BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | +--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
检查是否安装了FEDERATED插件
INSTALL PLUGIN federated SONAME 'ha_federated.so'; 1125 - Function 'federated' already exists
如果没有，打开MYSQL配置文件【my.ini】或者【my.cnf】配置FEDERATED参数
然后重启MYSQL服务
[mysqld] # mysql所在的目录 basedir=D:\mysql-8.0.28-winx64\ # mysql 数据库存储的目录 datadir=D:\mysql-8.0.28-winx64\data\ # mysql服务端默认使用的字符集 character-set-server=utf8 # 默认使用的存储引擎 default-storage-engine=INNODB # mysql服务端的端口号 port=3308 # 支持其它MYSQL以DBLINK方式访问本实例 federated # 关闭SSL认证 skip_ssl [mysql] # mysql客户端默认使用的字符集 default-character-set=utf8
再次检查是否开启
SHOW ENGINES; +--------------------+---------+----------------------------------------------------------------+--------------+-----+------------+ | Engine | Support | Comment | Transactions | XA | Savepoints | +--------------------+---------+----------------------------------------------------------------+--------------+-----+------------+ | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO | | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO | | CSV | YES | CSV storage engine | NO | NO | NO | | FEDERATED | YES | Federated MySQL storage engine | NO | NO | NO | | PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO | | MyISAM | YES | MyISAM storage engine | NO | NO | NO | | InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES | | BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | +--------------------+---------+----------------------------------------------------------------+--------------+-----+------------+
DBLINK访问测试：
在A库创建一张测试表以及数据：
CREATE TABLE `grade` ( `id` int NOT NULL, `job` varchar(32) COLLATE utf8mb4_general_ci NOT NULL, `score` int NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci; INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (1, 'C++', 11001); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (2, 'C++', 10000); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (3, 'C++', 9000); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (4, 'Java', 12000); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (5, 'Java', 13000); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (6, 'B', 12000); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (7, 'B', 11000); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (8, 'B', 9999); INSERT INTO `test`.`db-link-grade`(`id`, `job`, `score`) VALUES (9, 'C', 22344);
创建完成之后，在B库创建LINK表：
CREATE TABLE `db-link-grade` ( `id` int(11) NOT NULL, `job` varchar(32) NOT NULL, `score` int(11) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=FEDERATED DEFAULT CHARSET=utf8mb4 CONNECTION='mysql://root:123456@localhost:3308/nowcoder-sql/grade'; -- 指定表引擎为Federated ENGINE=FEDERATED -- 连接的目标表 CONNECTION='mysql://用户名:密码@目标Host:端口/库名/表名';
查询LINK表检查是否能成功访问：
SELECT * FROM `db-link-grade`; +----+------+-------+ | id | job | score | +----+------+-------+ | 1 | C++ | 11001 | | 2 | C++ | 10000 | | 3 | C++ | 9000 | | 4 | Java | 12000 | | 5 | Java | 13000 | | 6 | B | 12000 | | 7 | B | 11000 | | 8 | B | 9999 | | 9 | C | 22344 | +----+------+-------+
标签：NO,grade,跨库,DB,job,score,Link,YES,id 来源： https://www.cnblogs.com/mindzone/p/16377308.html