oracle创建与mysql的dblink

由于项目开发的需求，需要通过oracle访问mysql，必须配置“网关”,通过ODBC实现

总结了一下从oracle访问mysql的步骤：

1.先简单介绍下环境

操作系统：windows xp

oracle：10.0.2.0.1

mysql：5.0

2.下载mysql的odbc驱动，我用的是myodbc 3.5.1并安装

下载路径:http://dev.mysql.com/downloads/connector/odbc/3.51.html

3.配置odbc数据源，在控制面板中配置就可以了，使用系统DSN，取名为mysqltest

4.在E:/oracle/product/10.2.0/db_1/hs/admin下(E:/oracle/product/10.2.0/db_1为ORACLE_HOME的安装目录)建立initmysqltest.ora文件

输入：

HS_FDS_CONNECT_INFO = mysqltest

HS_FDS_TRACE_LEVEL = OFF

5.在E:/oracle/product/10.2.0/db_1/network/admin下修改

listener.ora

输入：

(SID_DESC =

(SID_NAME = mysql)

(ORACLE_HOME = E:/oracle/product/10.2.0/db_1)

(PROGRAM = hsodbc)

)

修改后的listener.ora如下:

SID_LIST_LISTENER =

(SID_LIST =

(SID_DESC =

(SID_NAME = PLSExtProc)

(ORACLE_HOME = E:/oracle/product/10.2.0/db_1)

(PROGRAM = extproc)

)

(SID_DESC =

(SID_NAME = mysql)

(ORACLE_HOME = E:/oracle/product/10.2.0/db_1)

(PROGRAM = hsodbc)

)

)

LISTENER =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))

)

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = MAJY)(PORT = 1521))

)

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = MAJY)(PORT = 1541))

)

)

6.修改tnsnames.ora

输入：

mysqltest =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = MAJY)(PORT = 1541))

(CONNECT_DATA =

(SID=mysqltest)

)

(HS =ok)

)

7.创建dblink

create public database link mysqllink

connect to “ws” identified by “ws”

using ‘mysqltest’;

要注意用户名和密码处需要用双引号，否则Oracle所传输的都是大写字母，可能无法登录进入MySQL。

8.访问mysql库中的表user

select “username” from “user”@mysqllink

由于MySQL中的表名的大小写敏感，因此需要在进行SQL查询时对表名用双引号扩起来