在日常工作中；经常会遇到这样的需求：
- Oracle 数据表跟文本或者文件格式进行交互；即将指定文件内容导入对应的 Oracle 数据表中；或者从 Oracle 数据表导出。
- 其他数据库中的表跟Oracle数据库进行交互。
若是少量数据；可选择的解决方案有很多。常用的用 Pl/SQL developer工具，或者手动转换为 INSERT 语句，或者通过API。但数据量大；用上面的方法效率太烂了。本文来说说 Oracle 数据的加载和卸载。
- Oracle中的DBLINK
- Oracle加载数据-外部表
- Oracle加载数据-sqlldr工具
- Oracle卸载数据-sqludr
一. Oracle 中的 DBLINK
在日常工作中；会遇到不同的数据库进行数据对接；每个数据库都有着功能；像Oracle有 DBLINK ; PostgreSQL有外部表。
1.1 Oracle DBlink 语法
CREATE [PUBLIC] DATABASE LINK link
CONNECT TO username
IDENTIFIED BY password
USING 'connectstring'
1.2 Oracle To Mysql
在oracle配置mysql数据库的dblink
二.Oracle加载数据-外部表
ORACLE外部表用来存取数据库以外的文本文件（Text File）或ORACLE专属格式文件。因此，建立外部表时不会产生段、区、数据块等存储结构，只有与表相关的定义放在数据字典中。外部表，顾名思义，存储在数据库外面的表。当存取时才能从ORACLE专属格式文件中取得数据，外部表仅供查询，不能对外部表的内容进行修改（INSERT、UPDATE、DELETE操作）。不能对外部表建立索引。
2.1 创建外部表需要的目录
# 创建外部表需要的目录SQL> create or replace directory DUMP_DIR as '/data/ora_ext_lottu'; Directory created.# 给用户授予指定目录的操作权限SQL> GRANT READ,WRITE ON DIRECTORY DUMP_DIR TO lottu;Grant succeeded.
2.2 外部表源文件lottu.txt
10,ACCOUNTING,NEW YORK20,RESEARCH,DALLAS30,SALES,CHICAGO40,OPERATIONS,BOSTON
2.3 创建外部表
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; 查看数据
SQL> select * from dept_external; DEPTNO DNAME LOC---------- -------------------- ------------------------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON
三. Oracle加载数据-sqlldr工具
3.1 准备实验对象
创建文件lottu.txt；和表tbl_load_01。
[oracle@oracle235 ~]$ seq 1000|awk -vOFS="," '{print $1,"lottu",systime()-$1}' > lottu.txt[oracle@oracle235 ~]$ sqlplus lottu/li0924SQL*Plus: Release 11.2.0.4.0 Production on Mon Aug 13 22:58:34 2018Copyright (c) 1982, 2013, Oracle. All rights reserved.Connected to:Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit ProductionWith the Partitioning, OLAP, Data Mining and Real Application Testing optionsSQL> create table tbl_load_01 (id number,name varchar2(10),accountid number);Table created. 3.2 创建控制文件lottu.ctl
load datacharacterset 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 执行sqlldr
[oracle@oracle235 ~]$ sqlldr 'lottu/"li0924"' control=/home/oracle/lottu.ctl log=/home/oracle/lottu.log bad=/home/oracle/lottu.badSQL*Loader: Release 11.2.0.4.0 - Production on Mon Aug 13 23:10:12 2018Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.Commit point reached - logical record count 64Commit point reached - logical record count 128Commit point reached - logical record count 192Commit point reached - logical record count 256Commit point reached - logical record count 320Commit point reached - logical record count 384Commit point reached - logical record count 448Commit point reached - logical record count 512Commit point reached - logical record count 576Commit point reached - logical record count 640Commit point reached - logical record count 704Commit point reached - logical record count 768Commit point reached - logical record count 832Commit point reached - logical record count 896Commit point reached - logical record count 960Commit point reached - logical record count 1000
四.Oracle卸载数据-sqludr
sqludr是将Oracle数据表导出到文本中；是牛人楼方鑫开发的。并非Oracle自带工具；需要下载安装才能使用。
4.1 sqludr安装
[oracle@oracle235 ~]$ unzip sqluldr2linux64.zip Archive: sqluldr2linux64.zip inflating: sqluldr2linux64.bin [oracle@oracle235 ~]$ mv sqluldr2linux64.bin $ORACLE_HOME/bin/sqludr
4.2 查看sqludr帮助
[oracle@oracle235 ~]$ 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 执行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.
总结
以上所述是小编给大家介绍的Oracle数据加载和卸载的实现方法，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对VeVb武林网网站的支持！
注：相关教程知识阅读请移步到oracle教程频道。
