SQL开发知识：Oracle数据加载和卸载的方法
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
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