外部表都是只读表 , 不能进行 update,insert,delete操作
Oracle 提供两种访问驱动 :
1.ORACLE_LOADER
ORACLE_LOADER利用oracle loader技术从外部表读取数据.
2.ORACLE_DATAPUMP
提供卸载数据的能力 , 即把数据从数据库里导入一个外部表 , 再由一个或几个外部表导入到数据库里。对于AS subquery 的子句必须使用 ORACLE_DATAPUMP . 创建用于卸载数据的外部表时,不能制定列名.
1.创建directory
(1)创建用户授予至少create any directory的权限
SQL> conn /as sysdba
Connected.
SQL>
SQL> create user test identified by test;
User created.
SQL> grant dba to test;
Grant succeeded.
(2)
SQL> host mkdir -p /u01/outdata
SQL> CREATE DIRECTORY ext_dir AS '/u01/outdata';
Directory created.
SQL> GRANT read,write on DIRECTORY ext_dir to test;
Grant succeeded.
2.基于oracle_datapump的外部表实现
(1)准备外部表创建脚本:
CREATE TABLE emp_xt
ORGANIZATION EXTERNAL
(
TYPE ORACLE_DATAPUMP
DEFAULT DIRECTORY ext_dir
LOCATION ('emp_xt.dmp')
)
AS SELECT * FROM scott.emp;
SQL> conn test/test
Connected.
SQL> CREATE TABLE emp_xt
2 ORGANIZATION EXTERNAL
3 (
4 TYPE ORACLE_DATAPUMP
5 DEFAULT DIRECTORY ext_dir
6 LOCATION ('emp_xt.dmp')
7 )
8 AS SELECT * FROM scott.emp;
Table created.
(2)验证表的正确性
[oracle@oraserv outdata]$ ls -lrt
total 16
-rw-r----- 1 oracle dba 12288 Jan 26 19:01 emp_xt.dmp
-rw-r--r-- 1 oracle dba 41 Jan 26 19:01 EMP_XT_2290.log
[oracle@oraserv outdata]$
SQL> select * from emp_xt;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
14 rows selected.
SQL> select * from emp_xt minus select * from scott.emp;
no rows selected
(3)删除外部表或者目录对象
一般情况下,先删除外部表,然后再删除目录对象,如果目录对象中有多个表,应删除所有表之后再删除目录对象。
如果在未删除外部表的情况下,强制删除了目录,在查询到被删除的外部表时,将收到"对象不存在"的错误信息。
(4)测试并行
CREATE TABLE emp_xt_1
ORGANIZATION EXTERNAL
(
TYPE ORACLE_DATAPUMP
DEFAULT DIRECTORY ext_dir
LOCATION ('emp_xt1.dmp', 'emp_xt2.dmp', 'emp_xt3.dmp')
)
PARALLEL 3
AS SELECT * FROM scott.emp;
比较数据:
SELECT * FROM scott.emp MINUS SELECT * FROM emp_xt_1;
SQL> SELECT * FROM scott.emp MINUS SELECT * FROM emp_xt_1;
no rows selected
2.基于oracle_loader的外部表
第一种创建办法:
EXAMPLE: Creating an External Table and Loading Data
The file empxt1.dat contains the following sample data:
360,Jane,Janus,ST_CLERK,121,17-MAY-2001,3000,0,50,jjanus
361,Mark,Jasper,SA_REP,145,17-MAY-2001,8000,.1,80,mjasper
362,Brenda,Starr,AD_ASST,200,17-MAY-2001,5500,0,10,bstarr
363,Alex,Alda,AC_MGR,145,17-MAY-2001,9000,.15,80,aalda
The file empxt2.dat contains the following sample data:
401,Jesse,Cromwell,HR_REP,203,17-MAY-2001,7000,0,40,jcromwel
402,Abby,Applegate,IT_PROG,103,17-MAY-2001,9000,.2,60,aapplega
403,Carol,Cousins,AD_VP,100,17-MAY-2001,27000,.3,90,ccousins
404,John,Richardson,AC_ACCOUNT,205,17-MAY-2001,5000,0,110,jrichard
建表语句如下:
CREATE TABLE ext_emply
(employee_id NUMBER(4),
first_name VARCHAR2(20),
last_name VARCHAR2(25),
job_id VARCHAR2(10),
manager_id NUMBER(4),
hire_date DATE,
salary NUMBER(8,2),
commission_pct NUMBER(2,2),
department_id NUMBER(4),
email VARCHAR2(25)
)
ORGANIZATION EXTERNAL
(
TYPE ORACLE_LOADER
DEFAULT DIRECTORY ext_dir
ACCESS PARAMETERS
(
records delimited by newline
fields terminated by ','
optionally enclosed by '"'
missing field values are null
( employee_id, first_name, last_name, job_id, manager_id,
hire_date char date_format date mask "dd-mon-yyyy",
salary, commission_pct, department_id, email
)
)
LOCATION ('empxt1.dat')
)
PARALLEL
REJECT LIMIT UNLIMITED;
第二种创建方法,利用sql loader
(1)创建数据源文本
SQL> select empno||','||ename||','||job||','||mgr||','||hiredate||','||sal||','||comm||','||deptno from emp;
EMPNO||','||ENAME||','||JOB||','||MGR||','||HIREDATE||','||SAL||','||COMM||','||DEPTNO
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
7369,SMITH,CLERK,7902,17-DEC-80,800,,20
7499,ALLEN,SALESMAN,7698,20-FEB-81,1600,300,30
7521,WARD,SALESMAN,7698,22-FEB-81,1250,500,30
7566,JONES,MANAGER,7839,02-APR-81,2975,,20
7654,MARTIN,SALESMAN,7698,28-SEP-81,1250,1400,30
7698,BLAKE,MANAGER,7839,01-MAY-81,2850,,30
7782,CLARK,MANAGER,7839,09-JUN-81,2450,,10
7788,SCOTT,ANALYST,7566,19-APR-87,3000,,20
7839,KING,PRESIDENT,,17-NOV-81,5000,,10
7844,TURNER,SALESMAN,7698,08-SEP-81,1500,0,30
7876,ADAMS,CLERK,7788,23-MAY-87,1100,,20
7900,JAMES,CLERK,7698,03-DEC-81,950,,30
7902,FORD,ANALYST,7566,03-DEC-81,3000,,20
7934,MILLER,CLERK,7782,23-JAN-82,1300,,10
(2)建议语句
CREATE TABLE emp_ext2 (
EMPNO NUMBER(4),
ENAME VARCHAR2(10),
JOB VARCHAR2(9),
MGR NUMBER(4),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2))
ORGANIZATION EXTERNAL
(TYPE ORACLE_LOADER DEFAULT DIRECTORY ext_dir
ACCESS PARAMETERS
(FIELDS TERMINATED BY ','
optionally enclosed by '"'
)
LOCATION ('ex_emp.txt')
);
验证方法
select * from emp_ext2 minus select EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO from emp;
SQL> select * from emp_ext2 minus select EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO from emp;
no rows selected
第三种创建方式sql loder
1.数据库源
[oracle@oraserv outdata]$ vi emp2xt.dat
7369,SMITH,CLERK,7902,17-DEC-80,800,,20
7499,ALLEN,SALESMAN,7698,20-FEB-81,1600,300,30
7521,WARD,SALESMAN,7698,22-FEB-81,1250,500,30
7566,JONES,MANAGER,7839,02-APR-81,2975,,20
7654,MARTIN,SALESMAN,7698,28-SEP-81,1250,1400,30
7698,BLAKE,MANAGER,7839,01-MAY-81,2850,,30
7782,CLARK,MANAGER,7839,09-JUN-81,2450,,10
7788,SCOTT,ANALYST,7566,19-APR-87,3000,,20
7839,KING,PRESIDENT,,17-NOV-81,5000,,10
7844,TURNER,SALESMAN,7698,08-SEP-81,1500,0,30
7876,ADAMS,CLERK,7788,23-MAY-87,1100,,20
7900,JAMES,CLERK,7698,03-DEC-81,950,,30
7902,FORD,ANALYST,7566,03-DEC-81,3000,,20
7934,MILLER,CLERK,7782,23-JAN-82,1300,,10
2.sql loader的控制文件emp2xt.ctl
load data
CHARACTERSET ZHS16GBK
infile './emp2xt.dat'
Append into table emp2xt
fields terminated by ','
optionally enclosed by '"'
trailing nullcols
(EMPNO,
ENAME,
JOB,
MGR,
HIREDATE DATE "DD-MM-YY" NULLIF (HIREDATE="NULL"),
SAL,
COMM,
DEPTNO
)
3.使用SQLLDR的“external_table=generate_only”参数生成外部表创建语句
sqlldr test/test control=emp2xt.ctl external_table=generate_only
[oracle@oraserv outdata]$ cat emp2xt.log
SQL*Loader: Release 10.2.0.1.0 - Production on Sat Jan 26 20:16:38 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Control File: emp2xt.ctl
Character Set ZHS16GBK specified for all input.
Data File: ./emp2xt.dat
Bad File: emp2xt.bad
Discard File: none specified
(Allow all discards)
Number to load: ALL
Number to skip: 0
Errors allowed: 50
Continuation: none specified
Path used: External Table
Table EMP2XT, loaded from every logical record.
Insert option in effect for this table: APPEND
TRAILING NULLCOLS option in effect
Column Name Position Len Term Encl Datatype
------------------------------ ---------- ----- ---- ---- ---------------------
EMPNO FIRST * , O(") CHARACTER
ENAME NEXT * , O(") CHARACTER
JOB NEXT * , O(") CHARACTER
MGR NEXT * , O(") CHARACTER
HIREDATE NEXT * , O(") DATE DD-MM-YY
NULL if HIREDATE = 0X4e554c4c(character 'NULL')
SAL NEXT * , O(") CHARACTER
COMM NEXT * , O(") CHARACTER
DEPTNO NEXT * , O(") CHARACTER
CREATE DIRECTORY statements needed for files
------------------------------------------------------------------------
CREATE DIRECTORY SYS_SQLLDR_XT_TMPDIR_00000 AS './'
CREATE TABLE statement for external table:
------------------------------------------------------------------------
CREATE TABLE "SYS_SQLLDR_X_EXT_EMP2XT"
(
"EMPNO" NUMBER(4),
"ENAME" VARCHAR2(10),
"JOB" VARCHAR2(9),
"MGR" NUMBER(4),
"HIREDATE" DATE,
"SAL" NUMBER(7,2),
"COMM" NUMBER(7,2),
"DEPTNO" NUMBER(2)
)
ORGANIZATION external
(
TYPE oracle_loader
DEFAULT DIRECTORY SYS_SQLLDR_XT_TMPDIR_00000
ACCESS PARAMETERS
(
RECORDS DELIMITED BY NEWLINE CHARACTERSET ZHS16GBK
BADFILE 'EXT_DIR':'emp2xt.bad'
LOGFILE 'emp2xt.log_xt'
READSIZE 1048576
FIELDS TERMINATED BY "," OPTIONALLY ENCLOSED BY '"' LDRTRIM
MISSING FIELD VALUES ARE NULL
REJECT ROWS WITH ALL NULL FIELDS
(
"EMPNO" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"ENAME" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"JOB" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"MGR" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"HIREDATE" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"'
DATE_FORMAT DATE MASK "DD-MM-YY"
NULLIF ("HIREDATE" = "NULL"),
"SAL" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"COMM" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"DEPTNO" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"'
)
)
location
(
'emp2xt.dat'
)
)REJECT LIMIT UNLIMITED
INSERT statements used to load internal tables:
------------------------------------------------------------------------
INSERT /*+ append */ INTO EMP2XT
(
EMPNO,
ENAME,
JOB,
MGR,
HIREDATE,
SAL,
COMM,
DEPTNO
)
SELECT
"EMPNO",
"ENAME",
"JOB",
"MGR",
"HIREDATE",
"SAL",
"COMM",
"DEPTNO"
FROM "SYS_SQLLDR_X_EXT_EMP2XT"
statements to cleanup objects created by previous statements:
------------------------------------------------------------------------
DROP TABLE "SYS_SQLLDR_X_EXT_EMP2XT"
DROP DIRECTORY SYS_SQLLDR_XT_TMPDIR_00000
Run began on Sat Jan 26 20:16:38 2013
Run ended on Sat Jan 26 20:16:38 2013
Elapsed time was: 00:00:00.26
CPU time was: 00:00:00.12
CREATE TABLE emp2xt_xt
(
"EMPNO" NUMBER(4),
"ENAME" VARCHAR2(10),
"JOB" VARCHAR2(9),
"MGR" NUMBER(4),
"HIREDATE" DATE,
"SAL" NUMBER(7,2),
"COMM" NUMBER(7,2),
"DEPTNO" NUMBER(2)
)
ORGANIZATION external
(
TYPE oracle_loader
DEFAULT DIRECTORY ext_dir
ACCESS PARAMETERS
(
RECORDS DELIMITED BY NEWLINE CHARACTERSET ZHS16GBK
FIELDS TERMINATED BY "," OPTIONALLY ENCLOSED BY '"' LDRTRIM
MISSING FIELD VALUES ARE NULL
REJECT ROWS WITH ALL NULL FIELDS
(
"EMPNO" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"ENAME" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"JOB" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"MGR" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"HIREDATE" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"'
DATE_FORMAT DATE MASK "DD-MM-YY"
NULLIF ("HIREDATE" = "NULL"),
"SAL" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"COMM" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"DEPTNO" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"'
)
)
location
(
'emp2xt.dat'
)
)REJECT LIMIT UNLIMITED;
验证外部表数据
SQL> select * from emp2xt_xt;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
14 rows selected.
3.从外部表到oracle表加载数据
1.创建内部表或者加载数据
create table employee as select * from ext_emply where 1=2;
2.insert into
SQL> insert into employee select * from ext_emply where EMPLOYEE_ID <=400;
5 rows created.
4.
select * from DBA_EXTERNAL_TABLES ;
select * from DBA_EXTERNAL_LOCATIONS ;
SQL> select OWNER,TABLE_NAME,TYPE_OWNER,TYPE_NAME,DEFAULT_DIRECTORY_NAME from DBA_EXTERNAL_TABLES;
OWNER TABLE_NAME TYP TYPE_NAME DEFAULT_DIRECTORY_NAME
------------------------------ ------------------------------ --- ------------------------------ ----------------
TEST EMP_XT SYS ORACLE_DATAPUMP EXT_DIR
SQL> col LOCATION format a50
SQL> select * from DBA_EXTERNAL_LOCATIONS
OWNER TABLE_NAME LOCATION DIR DIRECTORY_NAME
---------- ------------------------------ -------------------------------------------------- --- ------------------------------
TEST EMP_XT emp_xt.dmp SYS EXT_DIR