小小编
针对oracle数据库不同实例之间的数据访问，我们可以直接通过dblink访问，如果oracle数据库想访问mysql/sqlserver等数据库的数据，我们可以通过配置oracle透明网关实现异构数据库dblink访问。
这里将部署过程做个记录，希望对有需要的朋友有所帮助。
一、Oracle数据库通过透明网关访问MySQL数据库环境说明
RHEL6.6 oracle 11.2.0.4
RHEL6.6 MySQL5.7
odbc
二、数据访问流程
oracle——dg4odbc——odbc——mysql
三、Oracle透明网关（MySQL）安装
oracle 11.2.0.4默认安装了odbc透明网关
验证：
[oracle@test ~]$ cd $ORACLE_HOME/hs
[oracle@test hs]$ dg4odbc
Oracle Corporation --- FRIDAY APR 27 2018 10:07:44.375 Heterogeneous Agent Release 11.2.0.4.0 - 64bit Production Built with Oracle Database Gateway for ODBC
##database gateway for odbc 简称 dg4odbc
四、mysql-connector安装
下载：
https://dev.mysql.com/downloads/connector/odbc/
https://dev.mysql.com/get/Downloads/Connector-ODBC/8.0/mysql-connector-odbc-8.0.11-1.el6.x86_64.rpm
安装：
[root@test ~]# rpm -ivh mysql-connector-odbc-8.0.11-1.el6.x86_64.rpm warning: mysql-connector-odbc-8.0.11-1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY Preparing... ########################################### [100%] 1:mysql-connector-odbc ########################################### [100%] Success: Usage count is 1 Success: Usage count is 1
依赖包安装：
yum install unixODBC*
rpm -qa |grep unixODBC
unixODBC-devel-2.2.14-14.el6.x86_64
unixODBC-2.2.14-14.el6.x86_64
五、ODBC配置
[root@test ~]# vi /etc/odbc.ini
[mysql_test] Description = ODBC for MySQL Driver = /usr/lib64/libmyodbc8w.so Server = mysql_ipaddr Port = 3306 User = dbtest Password = abcd1234 Database = test
六、MySQL数据库创建账号、授权并测试连通性
账号创建： (root:localhost:Fri Apr 27 10:16:11 2018)[(none)]>create database test; (root:localhost:Fri Apr 27 10:16:22 2018)[(none)]>grant all on test.* to dbtest@\'%\' identified by \'abcd1234\'; (root:localhost:Fri Apr 27 10:16:40 2018)[(none)]>flush privileges; 连通性测试： [root@test ~]# isql mysql_test +---------------------------------------+ | Connected! | | | | sql-statement | | help [tablename] | | quit | | | +---------------------------------------+ SQL>
七、Oracle数据库相关配置
（1）hs透明网关配置
[oracle@test ~]$ cd $ORACLE_HOME/hs
[oracle@test hs]$ cd admin
[oracle@test admin]$ vi initmysql_test.ora
##HS Configuration HS_FDS_CONNECT_INFO = mysql_test HS_FDS_TRACE_LEVEL = debug HS_FDS_SHAREABLE_NAME = /usr/lib64/libodbc.so HS_FDS_SUPPORT_STATISTICS=FALSE HS_LANGUAGE=AMERICAN_AMERICA.zhs16gbk ##ODBC Configuration set ODBCINI=/etc/odbc.ini
##这里配置的是数据库实例名、odbc lib包，oracle数据库字符集、odbc配置文件路径
（2）监听配置
[oracle@test admin]$ vi /U01/app/oracle/product/11.2.0.4/network/admin/listener.ora
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME = dbsid)
(SID_NAME = dbsid)
(ORACLE_HOME=/U01/app/oracle/product/11.2.0.4)
)
(SID_DESC=
(SID_NAME=mysql_test)
(ORACLE_HOME=/U01/app/oracle/product/11.2.0.4)
(PROGRAM=dg4odbc)
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.1.1.1)(PORT = 1521))
)
)
重启监听
lsnrctl stop
lsnrctl start
（3）tnsname配置
配置tnsname
[oracle@test admin]$ vi /U01/app/oracle/product/11.2.0.4/network/admin/tnsnames.ora
dbsid_mysql =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.1.1.1 )(PORT = 1521))
)
(CONNECT_DATA =
(SID = mysql_test)
)
(HS = OK)
)
测试tnsname连接
[oracle@test admin]$ tnsping dbsid_mysql
TNS Ping Utility for Linux: Version 11.2.0.4.0 - Production on 27-APR-2018 12:17:58 Copyright (c) 1997, 2013, Oracle. All rights reserved. Used parameter files: Used TNSNAMES adapter to resolve the alias Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.1.1.1)(PORT = 1521))) (CONNECT_DATA = (SID = mysql_test)) (HS = OK)) OK (0 msec)
八、dblink创建以及数据访问测试
SQL>create PUBLIC DATABASE LINK dlk connect to "dbtest" identified by "abcd1234" using \'dbsid_mysql\'; SQL> select * from "t1"@dlk; id ---------- 10 11 SQL> insert into "t1"@dlk values(30); 1 row created.
九、错误信息以及处理方法
（1）错误01
错误信息：
SQL> select * from t1@dlk;
select * from t1@dlk
*
ERROR at line 1:
ORA-28500: connection from ORACLE to a non-Oracle system returned this message:
ORA-02063: preceding line from DLK
错误原因以及处理方法：hs/admin/init[sid].ora里配置的HS_FDS_SHAREABLE_NAME = /usr/lib64/libodbc.so不正确，应该是odbc的Lib包
（2）错误02
错误信息：
SQL> select * from "t1"@dlk;
select * from "t1"@dlk
*
ERROR at line 1:
ORA-28500: connection from ORACLE to a non-Oracle system returned this message:
[
错误原因以及处理方法：hs/admin/init[sid].ora里配置的HS_LANGUAGE=AMERICAN_AMERICA.zhs16gbk字符集不正确，应该是oracle数据库字符集
（3）错误03：
错误信息：
SQL> select * from t1@dlk;
select * from t1@dlk
*
ERROR at line 1:
ORA-00942: table or view does not exist
[MySQL][ODBC 8.0(w) Driver][mysqld-5.7.18-log]Table \'test.T1\' doesn\'t exist
{42S02,NativeErr = 1146}
ORA-02063: preceding 2 lines from DLK
错误原因以及处理方法：执行的查询操作，表名需要带双引号，因为mysql默认表名是区分大小写，而oracle是不区分大小写的 select * from “t1″@dlk;
