ORACLE客户端连服务器的注意事项：hR6TechFeel
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1. 通过SQL*NET协议，ORACLE客户端连服务器时一般需要配置sqlnet.ora和tnsnames.ora。hR6TechFeel
它们默认的目录在$ORACLE_HOME/network/admin 目录下hR6TechFeel
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也可以设置环境变量TNS_ADMIN指向你想用的sqlnet.ora和tnsnames.ora目录hR6TechFeel
例如：hR6TechFeel
TNS_ADMIN=/home/oracle/config/9.0.1;export TNS_ADMIN hR6TechFeel
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sqlnet.ora文件决定找数据库服务器别名的方式hR6TechFeel
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默认的参数有hR6TechFeel
NAMES.DEFAULT_DOMAIN = WORLDhR6TechFeel
NAMES.DIRECTORY_PATH = (TNSNAMES, ONAMES, HOSTNAME)hR6TechFeel
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如果你的ORACLE客户端和服务器默认的域名不一样，需要用#号注释第一行hR6TechFeel
#NAMES.DEFAULT_DOMAIN = WORLDhR6TechFeel
使它不起作用。hR6TechFeel
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NAMES.DIRECTORY_PATH指定找服务器别名的顺序 (本地的tnsnames.ora文件, 命名服务器, 主机名方式)hR6TechFeel
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服务器的sqlnet.ora里可以设置检查客户端是否alive的时间间隔hR6TechFeel
sqlnet.expire_time = 10hR6TechFeel
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tnsnames.ora文件里写数据库服务器别名的详细内容，有以下几种写法:hR6TechFeel
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# 一般的写法 hR6TechFeel
APPDB =hR6TechFeel
(DESCRIPTION =hR6TechFeel
(ADDRESS_LIST =hR6TechFeel
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.35)(PORT = 1521))hR6TechFeel
)hR6TechFeel
(CONNECT_DATA =hR6TechFeel
(SERVICE_NAME = appdb)hR6TechFeel
)hR6TechFeel
)hR6TechFeel
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# 明确标明用dedicated方式连接数据库hR6TechFeel
APPD= hR6TechFeel
(DESCRIPTION= hR6TechFeel
(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.0.35)(PORT=1521))hR6TechFeel
(CONNECT_DATA=hR6TechFeel
(SERVICE_NAME=appdb)hR6TechFeel
(SERVER=DEDICATED))) hR6TechFeel
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# 对多个listener端口做均衡负载方式连接数据库hR6TechFeel
APPS =hR6TechFeel
(DESCRIPTION =hR6TechFeel
(ADDRESS_LIST =hR6TechFeel
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.35)(PORT = 1521))hR6TechFeel
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.35)(PORT = 1856))hR6TechFeel
)hR6TechFeel
(CONNECT_DATA =hR6TechFeel
(SERVICE_NAME = appdb)hR6TechFeel
)hR6TechFeel
) hR6TechFeel
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# 注意：如果数据库服务器用MTS，客户端程序需要用database link时最好明确指明客户端用dedicated直连方式,hR6TechFeel
# 不然会遇到很多跟分布式环境有关的ORACLE BUG。hR6TechFeel
# 一般情况下数据库服务器用直接的连接会好一些，除非你的实时数据库连接数接近1000。hR6TechFeel
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2. /etc/hosts (UNIX)hR6TechFeel
或者windows\hosts(WIN98) winnt\system32\drivers\etc\hosts (WIN2000)hR6TechFeel
客户端需要写入数据库服务器IP地址和主机名的对应关系。hR6TechFeel
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127.0.0.1 localhosthR6TechFeel
192.168.0.35 oracledb oracledbhR6TechFeel
192.168.0.45 tomcat tomcathR6TechFeel
202.84.10.193 bj_db bj_db hR6TechFeel
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有些时候我们配置好第一步后，tnsping 数据库服务器别名显示是成功的，hR6TechFeel
但是sqlplus username/password@servicename不通,jdbc thin link 也不通的时候, hR6TechFeel
一定不要忘了在客户端做这一步，原因可能是DNS服务器里没有设置这个服务器IP地址和主机名的对应关系。hR6TechFeel
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如果同时有私有IP和Internet上公有IP，私有IP写在前面，公有IP写在后面。hR6TechFeel
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编辑前最好留一个备份，增加一行时也最好用复制粘贴，避免编辑hosts时空格或者tab字符错误。hR6TechFeel
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3. UNIX下ORACLE多数据库的环境，OS客户端需要配置下面两个环境变量hR6TechFeel
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ORACLE_SID=appdb;export ORACLE_SID hR6TechFeel
TWO_TASK=appdb;export TWO_TASK hR6TechFeel
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来指定默认的目标数据库。hR6TechFeel
