Table STUDENT:
3 Rows successfully loaded.
1 Row not loaded due to data errors.
0 Rows not loaded because all WHEN clauses were failed.
0 Rows not loaded because all fields were null.
Space allocated for bind array: 66048 bytes(64 rows)
Read buffer bytes: 1048576
Total logical records skipped: 4
Total logical records read: 4
Total logical records rejected: 1
Total logical records discarded: 0
Run began on Fri Jan 23 23:11:08 2015
Run ended on Fri Jan 23 23:11:08 2015
Elapsed time was: 00:00:00.10
CPU time was: 00:00:00.01
[oracle@localhost test_data_loader]$ sqlplus hr/hr
SQL*Plus: Release 11.2.0.1.0 Production on Fri Jan 23 23:13:14 2015
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> select * from student;
ID NAME AGE INNER_DATE
---------- -------------------- ---------- ------------
1 zhangsan 21 23-JAN-15
2 lisi 22 23-JAN-15
3 wangwu 23 23-JAN-15
SQL> exit
外部表：
外部表中的数据不装入数据库中，数据库中只存储外部表的定义信息，实际的数据位于操作系统的平面文件中，
但是，可以在数据库中，像访问正常表那样，通过select语句来访问操作系统中的平面文件中所含有的数据。
外部表是只读的。
可以使用SQL，PL/SQL和JAVA访问外部表。
外表表分为2种：使用数据泵引擎生成的外部表、
SQL> create table student_re(re_id,re_name,re_age,re_inner_date)
organization external
(
type oracle_datapump--外部表生成方式是数据泵
default directory test_impdp_expdp--默认的路径
location('student.dmp')--通过路径和文件名生成外部表在操作系统的平面数据文件
)
parallel--并行
as
select * from student; 2 3 4 5 6 7 8 9 10
Table created.
SQL> !ls
student.dmp STUENT_17109.log
SQL> select * from stuent;
RE_ID RE_NAME RE_AGE RE_INNER_DAT
---------- -------------------- ---------- ------------
1 zhangsan 21 23-JAN-15
2 lisi 22 23-JAN-15
3 wangwu 23 23-JAN-15
SQL>
根据文本文件创建的外部表。
SQL> spool student.txt
ID||','||NAME||','||AGE||','||INNER_DATE
--------------------------------------------------------------------------------
1,zhangsan,21,23-JAN-15
2,lisi,22,23-JAN-15
3,wangwu,23,23-JAN-15
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@localhost test_impdp_expdp]$ vi student.txt
[oracle@localhost test_impdp_expdp]$ sqlplus hr/hr
SQL*Plus: Release 11.2.0.1.0 Production on Sat Jan 24 00:05:18 2015
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> create table student_re_2--该外部表的名称下面列是外部表的建表语句，而上面通过数据泵的表是通过as select from tab来建立的。
2 (id number,name varchar2(20),age number(10),inner_date date)
3 organization external
4 ( type oracle_loader--外部文件方式
5 default directory test_impdp_expdp--默认的目录
6 access parameters--访问外部文件所遵守的格式
7 (
records delimited by newline--记录分隔符
fields terminated by ','--字段分隔符
8 ) location ('student.txt')--位置
); 9 10 11
Table created.
SQL> select * from student_re_2;