oracle如何通过dblink连接mysql

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本周由于公司一个系统的oracle数据库需要采集另一个系统mysql数据库的数据，于是对oracle通过dblink连接mysql进行了研究，测试环境是单实例oracle 10g 64位，折腾了半天搞定了，但是生产环境是10g rac，原本以为会很顺利，但是折腾了一天多都没搞定，问题主要出在监听上面，原本打算放弃，采用中间件连接mysql取数据，但是凭直觉感觉应该是单实例和rac的监听配置差异造成的，于是在rac节点上单独创建默认监听，问题果然解决了。

当配置有问题的时候都会报下面的错误：

ORA-28545: error diagnosed by Net8 when connecting to an agent
Unable to retrieve text of NETWORK/NCR message 65535

遇到的主要问题和解决办法有：

1、oracle 10g 64位的hsodbc应该有问题，文件大小为0，执行hsodbc没有任何信息；

解决：拷贝32机器下的hsodbc到$ORACLE_HOME/bin目录下，替换原hsodbc，注意oracle要有权限，下载：http://space.itpub.net/?uid-28321441-action-viewspace-itemid-750733

2、rac监听不能监听到hsodbc服务；

解决：netca选择single node configuration创建监听来监听hsodbc服务，监听端口选择1522；

3、连接mysql查询数据乱码。

解决：编辑/etc/odbc.ini，增加

charset      =gbk
STMT         =SET NAMES 'GBK'

其中gbk是MYSQL字符集。

具体实施步骤如下：

--oracle服务器：
-- 操作系统：Red Hat Enterprise Linux 5.3
-- 数据库：  Oracle RDBMS 10.2.0.3.0

--mysql服务器：
-- 操作系统：windows server 2003
-- 数据库：  MySQL 5.5

单实例操作如下，操作都在oracle服务器上完成：

--检查需要的rpm包，需要的包如下，由于hsodbc应该是只支持32位，所以32位包是必须的：
libtool-ltdl-1.5.22-6.1.i386.rpm
libtool-ltdl-1.5.22-6.1.x86_64.rpm
mysql-5.0.77-3.el5.i386.rpm
mysql-5.0.77-3.el5.x86_64.rpm
mysql-connector-odbc-3.51.26r1127-1.el5.i386.rpm
mysql-connector-odbc-3.51.26r1127-1.el5.x86_64.rpm
perl-DBI-1.52-2.el5.x86_64.rpm
unixODBC-2.2.11-7.1.i386.rpm
unixODBC-2.2.11-7.1.x86_64.rpm

上面unixODBC-2.2.11-7.1、mysql-5.0.77-3.el5、mysql-connector-odbc是需要的包，其他是安装这些包的前提。
安装完后检查
# rpm -qa |grep unixODBC

unixODBC-2.2.11-7.1
unixODBC-2.2.11-7.1

# rpm -qa |grep mysql

mysql-5.0.45-7.el5
mysql-5.0.45-7.el5
mysql-connector-odbc-3.51.26r1127-1.el5
mysql-connector-odbc-3.51.26r1127-1.el5

--编辑/etc/odbc.ini
vi /etc/odbc.ini

#[ODBC Data Sources]
#myodbc3     = MySQL ODBC 3.51 Driver DSN

[test]
Driver       = /usr/lib/libmyodbc3.so
Description  = MySQL ODBC 3.51 Driver DSN
SERVER       = 24.1.20.149
PORT         = 3306
USER         = root
Password     = laopo
Database     = teng_push
OPTION       = 3
SOCKET       =
charset      =gbk
STMT         =SET NAMES 'GBK'

--最后两个是解决中文乱码问题，gbk是MYSQL字符集

--切换到oracle用户
# su - oracle
--编辑环境变量配置文件，主要是LD_LIBRARY_PATH和最后面两项
$ vi ~/.bash_profile

export ORACLE_BASE=/oracle
export ORACLE_HOME=$ORACLE_BASE/product/10.2.0/db_1
export ORACLE_SID=orcl
export ORACLE_TERM=xterm
export PATH=/usr/sbin:$PATH
export NLS_LANG="SIMPLIFIED CHINESE_CHINA.ZHS16GBK"
#export LANG=zh_CN.GB18030
export PATH=.:$ORACLE_HOME/bin:$ORACLE_HOME/OPatch:$PATH:/bin:/usr/bin:/usr/sbin
:/usr/local/bin:/usr/X11R6/bin
export LD_LIBRARY_PATH=$ORACLE_HOME/lib32:$ORACLE_HOME/lib:/lib:/usr/lib
export CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib
#ulimit -u 16384 -n 65536
umask 022
export EDITOR=vi

ODBCINI=/etc/odbc.ini; export ODBCINI
ODBCSYSINI=/etc; export ODBCSYSINI

--使配置生效
source ~/.bash_profile

--查看odbc版本及参数文件路径
$odbcinst -j

unixODBC 2.2.11
DRIVERS............: /usr/local/etc/odbcinst.ini
SYSTEM DATA SOURCES: /usr/local/etc/odbc.ini
USER DATA SOURCES..: /usr/local/etc/odbc.ini

--测试 My SQL ODBC 驱动

$isql test -v(测试前需要将/etc/odbc.ini中的Driver= /usr/lib/libmyodbc3.so 修改成/usr/lib64/libmyodbc3.so，测试完后还原)

isql test oracle manager -v
+---------------------------------------+
| Connected!                            |
|                                       |
| sql-statement                         |
| help [tablename]                      |
| quit                                  |
|                                       |
+---------------------------------------+

SQL> quit

--配置 HSODBC 程序
vi $ORACLE_HOME/hs/admin/inittest.ora

HS_FDS_CONNECT_INFO = test
HS_FDS_TRACE_LEVEL = off
HS_FDS_SHAREABLE_NAME=/usr/lib/libmyodbc3.so
set DBCINI=/etc/odbc.ini

--确认 hsodbc 的配置是否正确，如果正确可以看到版本号
--注意：如果是64位oracle,由于hsodbc应该是只支持32位，这里需要拷贝32位机器上的hsodbc到$ORACLE_HOME/bin下替换原有的hsodbc

$ hsodbc

Oracle Corporation --- FRIDAY    DEC 06 2012 12:20:44.240

Heterogeneous Agent Release 10.2.0.3.0 - Production  Built with
   Driver for ODBC

--修改监听文件，增加下面服务：
    (SID_DESC =
      (PROGRAM = hsodbc)
      (ORACLE_HOME = /oracle/product/10.2.0/db_1)
      (SID_NAME = test)
      (ENVS=LD_LIBRARY_PATH = /oracle/product/10.2.0/db_1/lib32:/usr/lib:/oracle
/product/10.2.0/db_1/lib)
    ) 

$ vi $ORACLE_HOME/network/admin/listener.ora

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /oracle/product/10.2.0/db_1)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (PROGRAM = hsodbc)
      (ORACLE_HOME = /oracle/product/10.2.0/db_1)
      (SID_NAME = test)
      (ENVS=LD_LIBRARY_PATH = /oracle/product/10.2.0/db_1/lib32:/usr/lib:/oracle
/product/10.2.0/db_1/lib)
    ) 
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )
  )

--修改tnsnames.ora
$ vi $ORACLE_HOME/network/admin/tnsnames.ora

test =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS =(PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521)) 
    )    
    (CONNECT_DATA =
      (SID= test)
    )
    (HS=OK) 
  ) 

ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )

EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )

--重启监听，要有test服务
$ lsnrctl stop
$ lsnrctl start

Services Summary...
Service "PLSExtProc" has 1 instance(s).
  Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "orcl" has 1 instance(s).
  Instance "orcl", status UNKNOWN, has 1 handler(s) for this service...
Service "test" has 1 instance(s).
  Instance "test", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully

--tnsping测试服务
$ tnsping test

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS =(PROTOCOL = TCP)(HOST = 24.1.20.30)(PORT = 1521))) (CONNECT_DATA = (SID= test)) (HS=OK))
OK (0 msec)

--创建dblink
CREATE PUBLIC DATABASE LINK mysql CONNECT TO "root" IDENTIFIED BY "laopo" USING 'test';

--测试

select * from "emp"@mysql where "id"=1;

至此，单节点配置完成。

rac环境下每个节点都需要配置，和单实例唯一的区别是监听的配置，我试着多种方式去配置监听，但都没有监听到hsodbc的test服务，最后通过netca选择single node configuration创建监听来监听test服务才成功，注意监听端口改成1522

rac环境节点1的监听文件如下：

$vi $ORACLE_HOME/network/admin/listener.ora

SID_LIST_LISTENER_RAC01 =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /opt/ora10g/product/10.2.0/db_1)
      (PROGRAM = extproc)
    )
  )

LISTENER_RAC01 =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = rac01-vip)(PORT = 1521)(IP = FIRST))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 24.1.20.246)(PORT = 1521)(IP = FIRST))
    )
  )

SID_LIST_LISTENER1 =
  (SID_LIST =
    (SID_DESC =
      (PROGRAM=hsodbc)
      (ORACLE_HOME=/opt/ora10g/product/10.2.0/db_1)
      (SID_NAME=test)
      (ENVS=LD_LIBRARY_PATH=/opt/ora10g/product/10.2.0/db_1/lib32:/lib:/usr/lib:
/opt/ora10g/product/10.2.0/db_1/lib)
    )
  )

LISTENER1 =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 24.1.20.246)(PORT = 1522))
    )
  )

上述就是小编为大家分享的oracle如何通过dblink连接mysql实施了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注亿速云行业资讯频道。