Oracle数据加载和卸载的实现方法

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 YORK
20,RESEARCH,DALLAS
30,SALES,CHICAGO
40,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/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 创建控制文件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 执行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