"tb42" class="mar10">
目得：首先了解什么是外部表，与其它表的区别，建立一个简单的外部表（主要看操作过程），最后我们用外部表查看ORACLE报警日志 一．了解oracle外部表 外部表定义：结构被存放在数据字典，而表数据被放在OS文件中的表 作用：在数据库中查询OS文件的数据，还可以将OS文件数据装载到数据库中 与其它表的区别：在外部表上不能执行DML操作，也不能在外部表上建索引，只能执行0select操用 二．建一个简单的外部表 1．建一个OS上的文件 因为外部表主要是查看OS上的文件，首先在OS上建一个文件 mkdir -p /oracle/ext vi /oracle/ext/ext.dat 10,20,30 40,50,60 70,80,90 2．授予用户权限，并建立目录对象 在此我们先建一个新用户 create user test identified by “123” default tablespace test quota unlimited on test. 用户授权 SQL>. grant create any directory to test. 建立目录对象 SQL>. conn test / 123 Connected. SQL>. create directory ext as /oracle/ext . Directory created. 3.建立外部表 SQL>. create table exttable( id number,name varchar2(10),i number )organization external (type oracle_loader default directory ext access parameters (records delimited by newline fields terminated by , )location( ext.dat ) ). 4.测试 SQL>. 0select * from exttable. ID NAME I ---------- ---------- ---------- 10 20 30 40 50 60 70 80 90 测试成功,可见在数据库中可以查询OS文件的数据 二. 使用外部表查看oracle报警日志 由于在上面实验中已建立了一个用户,并赋相应的权限,而且也有了OS文件(即报警文件alert_SID.log),所以在此直接建立目录对象并建立外部表就可以了。 1．建立目录对象 SQL>. conn test / 123 Connected. SQL>. create directory bdump as /oracle/u01/app/oracle/admin/db2/bdump . Directory created. 2．建立外部表 SQL>. create table alert_log( text varchar2(400) )organization external (type oracle_loader default directory bdump access parameters (records delimited by newline )location( alert_db2.log ) ). 3．测试 首先查看能否查到alert_db2.log的内容 SQL>. 0select * from alert_log where rownum <. 10. TEXT Thu Jun 11 00:51:46 2009 Starting ORACLE instance (normal) Cannot determine all dependent dynamic libraries for /proc/self/exe Unable to find dynamic library libocr10.so in search paths RPATH = /ade/aime1_build2101/oracle/has/lib/:/ade/aime1_build2101/oracle/lib/:/a de/aime1_build2101/oracle/has/lib/: LD_LIBRARY_PATH is not set! The default library directories are /lib and /usr/lib Unable to find dynamic library libocrb10.so in search paths Unable to find dynamic library libocrutl10.so in search paths 9 rows 0selected. 测试成功 然后我们测试查报警信息’ORA-%’ SQL>. 0select * from alert_log where text like ORA-% . TEXT ORA-00202: control file: /oracle/u01/app/oracle/product/10.2.0/db2/dbs/cntrldb2 .dbf ORA-27037: unable to obtain file status ORA-205 signalled during: ALTER DATABASE MOUNT... ORA-00301: error in adding log file /home/oracle/oracle/oradata/testdb/redo01.l og - file cannot be created ORA-27040: file create error ORA-1501 signalled during: CREATE DATABASE db2 ORA-00200: control file could not be created TEXT ORA-00202: control file: /oracle/u01/app/oracle/product/10.2.0/db2/dbs/cntrldb2 .dbf ORA-27038: created file already exists ORA-1501 signalled during: CREATE DATABASE db2 ORA-00200: control file could not be created ORA-00202: control file: /oracle/u01/app/oracle/product/10.2.0/db2/dbs/cntrldb2 .dbf ORA-27038: created file already exists ORA-1501 signalled during: CREATE DATABASE db2 测试成功, 可见我们可以使用外部表来方便的查看ORACLE的报警信息. 更多优质资料尽在百考试题论坛百考试题在线题库oracle/认证更多详细资料