oracle_外部表的两种实现方式oracle_loader[datapump]

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本篇文章主要介绍了"oracle_外部表的两种实现方式oracle_loader[datapump] ",主要涉及到oracle_外部表的两种实现方式oracle_loader[datapump] 方面的内容,对于oracle_外部表的两种实现方式oracle_loader[datapump] 感兴趣的同学可以参考一下。

外部表可以实现,通过数据库对象直接访问目录文件里的格式数据,加载方式分为两种oracle_loader和oracle_datapump,oracle_loader方式通过sqlldr引擎方式加载,访问flat格式文件;oracle_datapump通过datapump接口来加载,访问通过oracle_datapump方式卸载的dmp文件;
 
 
 
 
------oracle_loader
----自定义两个格式文件内容如下:
====a.dat====
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
 
====b.dat====
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
 
 
----创建需要的目录
CONNECT  /  AS SYSDBA;
-- Set up directories and grant access to hr 
CREATE OR REPLACE DIRECTORY admin_dat_dir
    AS '/u01/backup'; 
CREATE OR REPLACE DIRECTORY admin_log_dir 
    AS '/u01/backup'; 
CREATE OR REPLACE DIRECTORY admin_bad_dir 
    AS '/u01/backup'; 
GRANT READ ON DIRECTORY admin_dat_dir TO sun; 
GRANT WRITE ON DIRECTORY admin_log_dir TO sun; 
GRANT WRITE ON DIRECTORY admin_bad_dir TO sun;
 
----通过loader方式创建外部表,直接通过表来查询操作
conn sun/sun
-- create the external table
CREATE TABLE admin_ext_employees
                   (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 admin_dat_dir 
       ACCESS PARAMETERS 
       ( 
         records delimited by newline 
         badfile admin_bad_dir:'empxt%a_%p.bad' 
         logfile admin_log_dir:'empxt%a_%p.log' 
         fields terminated 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 ('a.dat', 'b.dat') 
     ) 
     PARALLEL 
     REJECT LIMIT UNLIMITED; 
     
create table emp as select * from admin_ext_employees;     
 
 
SQL> 
SQL> SELECT * FROM emp;
 
EMPLOYEE_ID FIRST_NAME           LAST_NAME                 JOB_ID     M
----------- -------------------- ------------------------- ---------- -
        401 Jesse                Cromwell                  HR_REP      
        402 Abby                 Applegate                 IT_PROG     
        403 Carol                Cousins                   AD_VP       
        404 John                 Richardson                AC_ACCOUNT  
        360 Jane                 Janus                     ST_CLERK    
        361 Mark                 Jasper                    SA_REP      
        362 Brenda               Starr                     AD_ASST     
        363 Alex                 Alda                      AC_MGR      
SQL> SELECT * FROM user_external_tables ;
 
no rows selected
 
 
[ora11@prim backup]$ ls -l
total 20
-rw-r--r-- 1 ora11 oinstall  228 Sep  6 21:17 a.dat
-rw-r--r-- 1 ora11 oinstall  252 Sep  6 21:17 b.dat
-rw-r--r-- 1 ora11 oinstall 2826 Sep  6 21:19 empxt000_2756.log
-rw-r--r-- 1 ora11 oinstall 3110 Sep  6 21:19 empxt000_2763.log
-rw-r--r-- 1 ora11 oinstall 3110 Sep  6 21:19 empxt001_2765.log
 
 
------oracle_datapump
----更多是实现数据迁移的功能,通过datapump方式卸载并迁移到其他系统;
----创建datapump方式的外部表,并将数据卸载到目录文件中;
SQL> CREATE TABLE admin_ext_employees
  2                     (employee_id     ,
  3                      first_name      ,
  4                      last_name       , 
  5                      job_id          ,
  6                      manager_id      ,
  7                      hire_date       ,
  8                      salary          ,
  9                      commission_pct  ,
 10                      department_id   ,
 11                      email           
 12                     ) 
 13       ORGANIZATION EXTERNAL 
 14       ( 
 15         TYPE ORACLE_DATAPUMP 
 16         DEFAULT DIRECTORY admin_dat_dir 
 17         LOCATION ('emp2.dmp'))
 18        AS SELECT  * FROM emp;
 
Table created.
 
----查询文件内容,大体是产生XML格式的文件
-rw-r----- 1 ora11 oinstall 12288 Sep  6 21:33 emp2.dmp
[ora11@prim backup]$ strings emp2.dmp 
"SUN"."U"
x86_64/Linux 2.4.xx
 
 
----通过loader方式创建外部表,直接通过表来查询操作
SQL> CREATE TABLE admin_ext_employees2
  2                     (employee_id       NUMBER(4), 
  3                      first_name        VARCHAR2(20),
  4                      last_name         VARCHAR2(25), 
  5                      job_id            VARCHAR2(10),
  6                      manager_id        NUMBER(4),
  7                      hire_date         DATE,
  8                      salary            NUMBER(8,2),
  9                      commission_pct    NUMBER(2,2),
 10                      department_id     NUMBER(4),
 11                      email             VARCHAR2(25) 
 12                     ) 
 13       ORGANIZATION EXTERNAL 
 14       ( 
 15         TYPE ORACLE_DATAPUMP 
 16         DEFAULT DIRECTORY admin_dat_dir 
 17         LOCATION ('emp2.dmp')) ;
 
Table created.
 
SQL> 
SQL> SELECT * FROM admin_ext_employees2 ;
 
EMPLOYEE_ID FIRST_NAME           LAST_NAME                 JOB_ID    
----------- -------------------- ------------------------- ----------
        401 Jesse                Cromwell                  HR_REP    
        402 Abby                 Applegate                 IT_PROG   
        403 Carol                Cousins                   AD_VP     
        404 John                 Richardson                AC_ACCOUNT
        360 Jane                 Janus                     ST_CLERK  
        361 Mark                 Jasper                    SA_REP    
        362 Brenda               Starr                     AD_ASST   
        363 Alex                 Alda                      AC_MGR    


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