在日常工作中；經常會遇到這樣的需求：

• Oracle 資料表跟文字或者檔案格式進行互動；即將指定檔案內容匯入對應的 Oracle 資料表中；或者從 Oracle 資料表匯出。
• 其他資料庫中的表跟Oracle資料庫進行互動。

　　若是少量資料；可選擇的解決方案有很多。常用的用 Pl/SQL developer工具，或者手動轉換為 INSERT 語句，或者通過API。但資料量大；用上面的方法效率太爛了。本文來說說 Oracle 資料的載入和解除安裝。

• Oracle中的DBLINK
• Oracle載入資料-外部表
• Oracle載入資料-sqlldr工具
• Oracle解除安裝資料-sqludr

一. Oracle 中的 DBLINK

　　在日常工作中；會遇到不同的資料庫進行資料對接；每個資料庫都有著功能；像Oracle有 DBLINK ; PostgreSQL有外部表。

1.1 Oracle DBlink 語法

CREATE [PUBLIC] DATABASE LINK link
CONNECT TO username
IDENTIFIED BY password
USING 'connectstring'

1.2 Oracle To Mysql

　　在oracle配置mysql資料庫的dblink

二.Oracle載入資料-外部表

　　ORACLE外部表用來存取資料庫以外的文字檔案（Text File）或ORACLE專屬格式檔案。因此，建立外部表時不會產生段、區、資料塊等儲存結構，只有與表相關的定義放在資料字典中。外部表，顧名思義，儲存在資料庫外面的表。當存取時才能從ORACLE專屬格式檔案中取得資料，外部表僅供查詢，不能對外部表的內容進行修改（INSERT、UPDATE、DELETE操作）。不能對外部表建立索引。

2.1 建立外部表需要的目錄

# 建立外部表需要的目錄
SQL> create or replace directory DUMP_DIR as '/data/ora_ext_lottu'; 
Directory created.
# 給使用者授予指定目錄的操作許可權
SQL> GRANT READ,WRITE ON DIRECTORY DUMP_DIR TO lottu;

Grant succeeded.

2.2 外部表原始檔lottu.txt

10,ACCOUNTING,NEW YORK
20,RESEARCH,DALLAS
30,SALES,CHICAGO
40,OPERATIONS,BOSTON

2.3 建立外部表

drop table dept_external purge;

CREATE TABLE dept_external (
  deptno   NUMBER(6),dname   VARCHAR2(20),loc    VARCHAR2(25) 
)
ORGANIZATION EXTERNAL
(TYPE oracle_loader
 DEFAULT DIRECTORY DUMP_DIR
 ACCESS PARAMETERS
 (
 RECORDS DELIMITED BY newline
 BADFILE 'lottu.bad'
 LOGFILE 'lottu.log'
 FIELDS TERMINATED BY "," OPTIONALLY ENCLOSED BY '"'
 (
  deptno   INTEGER EXTERNAL(6),dname   CHAR(20),loc    CHAR(25)
 )
 )
 LOCATION ('lottu.txt')
)
REJECT LIMIT UNLIMITED;

檢視資料

SQL> select * from dept_external;

  DEPTNO DNAME LOC
---------- -------------------- -------------------------
 10 ACCOUNTING NEW YORK
 20 RESEARCH DALLAS
 30 SALES CHICAGO
 40 OPERATIONS BOSTON

三. Oracle載入資料-sqlldr工具

3.1 準備實驗物件

　　建立檔案lottu.txt；和表tbl_load_01。

[oracle@oracle235 ~]$ seq 1000|awk -vOFS="," '{print $1,"lottu",systime()-$1}' > lottu.txt
[oracle@oracle235 ~]$ sqlplus lottu/li0924
SQL*Plus: Release 11.2.0.4.0 Production on Mon Aug 13 22:58:34 2018
Copyright (c) 1982,2013,Oracle. All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning,OLAP,Data Mining and Real Application Testing options
SQL> create table tbl_load_01 (id number,name varchar2(10),accountid number);
Table created.

3.2 建立控制檔案lottu.ctl

load data
characterset utf8
    infile '/home/oracle/lottu.txt'
    truncate into table tbl_load_01
    fields terminated by ','
    trailing nullcols
 optionally enclosed by ' ' TRAILING NULLCOLS
(
 id,name,accountid
)

3.3 執行sqlldr

[oracle@oracle235 ~]$ sqlldr 'lottu/"li0924"' control=/home/oracle/lottu.ctl log=/home/oracle/lottu.log bad=/home/oracle/lottu.bad
SQL*Loader: Release 11.2.0.4.0 - Production on Mon Aug 13 23:10:12 2018
Copyright (c) 1982,2011,Oracle and/or its affiliates. All rights reserved.
Commit point reached - logical record count 64
Commit point reached - logical record count 128
Commit point reached - logical record count 192
Commit point reached - logical record count 256
Commit point reached - logical record count 320
Commit point reached - logical record count 384
Commit point reached - logical record count 448
Commit point reached - logical record count 512
Commit point reached - logical record count 576
Commit point reached - logical record count 640
Commit point reached - logical record count 704
Commit point reached - logical record count 768
Commit point reached - logical record count 832
Commit point reached - logical record count 896
Commit point reached - logical record count 960
Commit point reached - logical record count 1000

四.Oracle解除安裝資料-sqludr

　　sqludr是將Oracle資料表匯出到文字中；是牛人樓方鑫開發的。並非Oracle自帶工具；需要下載安裝才能使用。

4.1 sqludr安裝

[oracle@oracle235 ~]$ unzip sqluldr2linux64.zip 
Archive: sqluldr2linux64.zip
 inflating: sqluldr2linux64.bin   
[oracle@oracle235 ~]$ mv sqluldr2linux64.bin $ORACLE_HOME/bin/sqludr

4.2 檢視sqludr幫助

[oracle@oracle235 ~]$ sqludr -?
SQL*UnLoader: Fast Oracle Text Unloader (GZIP,Parallel),Release 4.0.1
(@) Copyright Lou Fangxin (AnySQL.net) 2004 - 2010,all rights reserved.
License: Free for non-commercial useage,else 100 USD per server.
Usage: SQLULDR2 keyword=value [,keyword=value,...]
Valid Keywords:
  user  = username/password@tnsname
  sql   = SQL file name
  query  = select statement
  field  = separator string between fields
  record = separator string between records
  rows  = print progress for every given rows (default,1000000) 
  file  = output file name(default: uldrdata.txt)
  log   = log file name,prefix with + to append mode
  fast  = auto tuning the session level parameters(YES)
  text  = output type (MYSQL,CSV,MYSQLINS,ORACLEINS,FORM,SEARCH).
  charset = character set name of the target database.
  ncharset= national character set name of the target database.
  parfile = read command option from parameter file 
 for field and record,you can use '0x' to specify hex character code,\r=0x0d \n=0x0a |=0x7c,=0x2c,\t=0x09,:=0x3a,#=0x23,"=0x22 '=0x27

4.3 執行sqludr

[oracle@oracle235 ~]$ sqludr lottu/li0924 query="tbl_load_01" file=lottu01.txt field=","
      0 rows exported at 2018-08-13 23:47:55,size 0 MB.
    1000 rows exported at 2018-08-13 23:47:55,size 0 MB.
     output file lottu01.txt closed at 1000 rows,size 0 MB.

總結

以上所述是小編給大家介紹的Oracle資料載入和解除安裝的實現方法，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回覆大家的。在此也非常感謝大家對我們網站的支援！