文章摘要
SQL*Loader 是 Oracle 提供的一个用于将数据从一个 Oracle 数据源导入到另一个 Oracle 数据源的工具。它支持从数据库、 tablespaces、 tablespaces with indexes、 tablespaces with partitions 以及外部表（ETABLE）加载数据。
SQL*Loader 的核心功能包括：
- **userid**：设置 Oracle 用户名和密码
- **control**：指定控制文件名
- **log**：指定日志文件名
- **bad**：指定无效记录文件名
- **data**：指定数据文件名
- **discard**：指定丢弃文件名
- **skip**：跳过逻辑记录数
- **load**：加载逻辑记录数
- **errors**：允许的错误记录数
命令格式为：`SQLLDR [KEYWORD=VALUE [...]]`，其中参数可以使用位置参数或关键词参数。位置参数必须在关键词参数之前。SQL*Loader 还支持并行加载（parallel）、多线程（multithreading）、以及设置丢弃记录数（discard）、日志大小（logsize）、数据文件大小（datafilesize）等高级选项。
[oracle@centos5 ~]$ sqlldr
SQL*Loader: Release 10.2.0.4.0 – Production on Thu Jun 13 17:07:26 2013
Copyright (c) 1982, 2007, Oracle. All rights reserved.
Usage: SQLLDR keyword=value [,keyword=value,…]
Valid Keywords:
userid — ORACLE username/password
control — control file name
log — log file name
bad — bad file name
data — data file name
discard — discard file name
discardmax — number of discards to allow (Default all)
skip — number of logical records to skip (Default 0)
load — number of logical records to load (Default all)
errors — number of errors to allow (Default 50)
rows — number of rows in conventional path bind array or between direct path data saves
(Default: Conventional path 64, Direct path all)
bindsize — size of conventional path bind array in bytes (Default 256000)
silent — suppress messages during run (header,feedback,errors,discards,partitions)
direct — use direct path (Default FALSE)
parfile — parameter file: name of file that contains parameter specifications
parallel — do parallel load (Default FALSE)
file — file to allocate extents from
skip_unusable_indexes — disallow/allow unusable indexes or index partitions (Default FALSE)
skip_index_maintenance — do not maintain indexes, mark affected indexes as unusable (Default FALSE)
commit_discontinued — commit loaded rows when load is discontinued (Default FALSE)
readsize — size of read buffer (Default 1048576)
external_table — use external table for load; NOT_USED, GENERATE_ONLY, EXECUTE (Default NOT_USED)
columnarrayrows — number of rows for direct path column array (Default 5000)
streamsize — size of direct path stream buffer in bytes (Default 256000)
multithreading — use multithreading in direct path
resumable — enable or disable resumable for current session (Default FALSE)
resumable_name — text string to help identify resumable statement
resumable_timeout — wait time (in seconds) for RESUMABLE (Default 7200)
date_cache — size (in entries) of date conversion cache (Default 1000)
PLEASE NOTE: Command-line parameters may be specified either by
position or by keywords. An example of the former case is ‘sqlldr
scott/tiger foo’; an example of the latter is ‘sqlldr control=foo
userid=scott/tiger’. One may specify parameters by position before
but not after parameters specified by keywords. For example,
‘sqlldr scott/tiger control=foo logfile=log’ is allowed, but
‘sqlldr scott/tiger control=foo log’ is not, even though the
position of the parameter ‘log’ is correct.