1.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select操用
2.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> select * 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
2. 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> select * 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 selected. |
测试成功
然后我们测试查报警信息'ORA-%'
|
SQL> select * 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.