在日常工作中；經常會遇到這樣的需求：
- Oracle 數據表跟文本或者文件格式進行交互；即將指定文件內容導入對應的 Oracle 數據表中；或者從 Oracle 數據表導出。
- 其他數據庫中的表跟Oracle數據庫進行交互。
若是少量數據；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。但數據量大；用上面的方法效率太爛了。本文來說說 Oracle 數據的加載和卸載。
- Oracle中的DBLINK
- Oracle加載數據-外部表
- Oracle加載數據-sqlldr工具
- Oracle卸載數據-sqludr
一. Oracle 中的 DBLINK
在日常工作中；會遇到不同的數據庫進行數據對接；每個數據庫都有著功能；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數據庫的dblink
二.Oracle加載數據-外部表
ORACLE外部表用來存取數據庫以外的文本文件（Text File）或ORACLE專屬格式文件。因此，建立外部表時不會產生段、區、數據塊等存儲結構，只有與表相關的定義放在數據字典中。外部表，顧名思義，存儲在數據庫外面的表。當存取時才能從ORACLE專屬格式文件中取得數據，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 創建外部表需要的目錄
# 創建外部表需要的目錄
SQL> create or replace directory DUMP_DIR as '/data/ora_ext_lottu';
Directory created.
# 給用戶授予指定目錄的操作權限
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 創建外部表
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;
查看數據
SQL> select * from dept_external;
DEPTNO DNAME LOC
---------- -------------------- -------------------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
三. Oracle加載數據-sqlldr工具
3.1 準備實驗對象
創建文件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 創建控制文件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 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卸載數據-sqludr
sqludr是將Oracle數據表導出到文本中；是牛人樓方鑫開發的。并非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 $ORACLE_HOME/bin/sqludr
4.2 查看sqludr幫助
[oracle@oracle235 ~]$ 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數據加載和卸載的實現方法，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對腳本之家網站的支持！
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