MYSQL建立dblink數據同步MySQL數據庫視圖的創建

MySQL數據庫視圖的創建，需要整合兩個位於不同服務器上數據庫的內容，就遇到了遠程訪問數據庫的問題。在cracle中可以通過dblink來實現跨本地數據庫來訪問另外一個數據庫中的數據。通過在網上查找，發現可以通過MySQL中的federated插件來實現類似的功能。

操作環境：

宿主機為win8系統，MySQL數據庫，ip：192.168.1.98；從機為VMware虛擬機中的Linux系統，版本為CentOS6.5，MySQL數據庫，ip：192.168.1.106。

實現功能：

可以在Linux系統中MySQL數據庫（target端）中建立宿主機MySQL數據庫（source端）中某個表的link，當在Linux中讀取link表時，就相當於直接讀取宿主機中的原始表內容。

實現步驟：

1. 查看target端（Linux虛擬機中）是否安裝了federated插件：

mysql> show engines;

±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+
| CSV | YES | CSV 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 |
| FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+

顯示沒有安裝federated插件

2. 安裝federated插件：

mysql>install plugin federated soname ‘ha_federated.so’;

ERROR 1125 (HY000): Function ‘federated’ already exists

說明已經安裝過了，但沒有啟用

[root@localhost etc]# service mysql stop

[root@localhost etc]# mysqld_safe --federated &

[root@localhost etc]# 140811 01:20:21 mysqld_safe Logging to ‘/var/lib/mysql/localhost.localdomain.err’.
140811 01:20:22 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

mysql> show engines;

±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+
| CSV | YES | CSV 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 |
| FEDERATED |YES | Federated MySQL storage engine | NULL | NULL | NULL |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+

federated插件已經啟用

3. 配置/etc/my.conf，設置federated為默認啟動

[root@localhost etc]# vi /etc/my.conf

在文件中加入一行：

federated

重啟mysql服務

service mysql restart

mysql> show engines;

±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+
| CSV | YES | CSV 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 |
| FEDERATED | YES | Federated MySQL storage engine | NULL | NULL | NULL |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
±-------------------±--------±---------------------------------------------------------------±-------------±-----±-----------+

已經設置為默認啟動了。

4. 在source端建立測試表，我是通過Navicat建立表的，其sql文件為：

DROP TABLE IF EXISTS e_eledata;
CREATE TABLE e_eledata (
ID bigint(20) unsigned NOT NULL auto_increment COMMENT ‘ID’,
E_ELEMETERHEAD_ID bigint(20) default NULL COMMENT ‘電表表頭ID’,
DAQDT timestamp NULL default NULL COMMENT ‘數據采集時間’,
DLDT timestamp NULL default NULL COMMENT ‘數據入庫時間’,
APCURRENT decimal(10,3) default NULL COMMENT ‘A相電流。單位：A。’,
BPCURRENT decimal(10,3) default NULL COMMENT ‘B相電流。單位：A。’,
CPCURRENT decimal(10,3) default NULL COMMENT ‘C相電流。單位：A。’,
APVOLTAGE decimal(10,3) default NULL COMMENT ‘A相電壓。單位：V。’,
BPVOLTAGE decimal(10,3) default NULL COMMENT ‘B相電壓。單位：V。’,
CPVOLTAGE decimal(10,3) default NULL COMMENT ‘C相電壓。單位：V。’,
PRIMARY KEY (ID)
) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COMMENT=‘電路數據表’;

5. 在target端建立link表，可以直接改寫source表的sql腳本文件為：

DROP TABLE IF EXISTS e_eledata_link;
CREATE TABLE e_eledata_link (
ID bigint(20) unsigned NOT NULL auto_increment COMMENT ‘ID’,
E_ELEMETERHEAD_ID bigint(20) default NULL COMMENT ‘電表表頭ID’,
DAQDT timestamp NULL default NULL COMMENT ‘數據采集時間’,
DLDT timestamp NULL default NULL COMMENT ‘數據入庫時間’,
APCURRENT decimal(10,3) default NULL COMMENT ‘A相電流。單位：A。’,
BPCURRENT decimal(10,3) default NULL COMMENT ‘B相電流。單位：A。’,
CPCURRENT decimal(10,3) default NULL COMMENT ‘C相電流。單位：A。’,
APVOLTAGE decimal(10,3) default NULL COMMENT ‘A相電壓。單位：V。’,
BPVOLTAGE decimal(10,3) default NULL COMMENT ‘B相電壓。單位：V。’,
CPVOLTAGE decimal(10,3) default NULL COMMENT ‘C相電壓。單位：V。’,
PRIMARY KEY (ID)
) ENGINE=FEDERATEDAUTO_INCREMENT=1DEFAULT CHARSET=utf8 COMMENT=‘電路數據表’

CONNECTION='mysql://usrname:password@192.168.1.98:3306/databasename/table

其中：

usrname為宿主機中MySQL的用戶名

password為相應的密碼

（要保證該用戶具有遠程登陸的權限，可以通過以下命令來設置：

mysql>GRANT ALL PRIVILEGES ON . TO ‘usrname’@’%’ IDENTIFIED BY ‘password’ WITH GRANT OPTION;

其中*.*是指對用戶開放所有數據庫和表的權限，如果只開放某一個數據庫的一個表為databasename.table；’%‘指的是該用戶可以從任意的一個ip地址來遠程訪問數據庫，包括本地，如果要限制用戶從特定的ip來訪問，將其改為’ip地址’）

192.168.1.98是source數據庫的ip，這里為我宿主機的ip

3306為數據庫的端口，默認一般為3306

database 和table分別為source端數據庫的名稱和表名稱

將該sql腳本在target端運行

6. 實現跨本地數據庫的訪問

在target端通過訪問e_eledata_link表來訪問source端e_eledata表

mysql> select *from e_eledata_link;

 

 

MYSQL建立dblink數據同步MySQL數據庫視圖的創建

 

mysql的dblink就是訪問目標數據庫，通過dblink連接的方式來訪問到源數據庫的數據。

這里源端為遠程服務器，目標端為本地

查看本地mysql的有沒有federated 引擎：
mysql> show engines;

+--------------------+---------+------------------------------------------------
----------------+--------------+------+------------+
| Engine | Support | Comment
| Transactions | XA | Savepoints |
+--------------------+---------+------------------------------------------------
----------------+--------------+------+------------+
| InnoDB | DEFAULT | Supports transactions, row-level locking, and f
oreign keys | YES | YES | YES |
| MRG_MYISAM | YES | Collection of identical MyISAM tables
| NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for tempor
ary tables | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to
it disappears) | NO | NO | NO |
| MyISAM | YES | MyISAM storage engine
| NO | NO | NO |
| CSV | YES | CSV storage engine
| NO | NO | NO |
| ARCHIVE | YES | Archive storage engine
| NO | NO | NO |
| PERFORMANCE_SCHEMA | YES | Performance Schema
| NO | NO | NO |
| FEDERATED | NO | Federated MySQL storage engine
| NULL | NULL | NULL |
+--------------------+---------+------------------------------------------------
----------------+--------------+------+------------+

安裝了federated，但沒啟動。（如果沒有安裝FEDERATED 引擎        執行install plugin federated soname 'ha_federated.so';）

在mysql目錄下的my.ini文件里添加一行

federated

重啟mysql服務，然后查看federated 

mysql> show engines;

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

看到已開啟

在本地創建和遠程數據庫的表的表結構一致的表，以及遠程數據庫的連接：例如

CREATE TABLE dblink_view (
bank_name VARCHAR(50),
sys_bank_code VARCHAR(12),
PROV_INPUT_NAME VARCHAR(20),
NAME VARCHAR(10)
)ENGINE=FEDERATED CONNECTION='mysql://bankinfo:bankinfo@192.168.3.42:3307/t2_cpv2/view_bt_input_bank_info';

 engine=federated connection = 'mysql://用戶:密碼@IP地址:端口/庫名稱/表名稱';

完成后就可以本地數據庫查到遠程庫數據：SELECT * FROM dblink_view；