使用 DB2 的LOAD FROM CURSOR 特性快速轻松地转移数据

中文字数:5926,中文页数:16  英文字数:4335页数:25

Introduction
Typical DB2 data movement tasks involve three steps:
Exporting the data from the source database into a temporary data exchange file in binary or text format
Moving the generated file between systems
Importing or loading the data from the file into the target database.
Generating the data exchange file using the EXPORT utility is often a lengthy process in the case of large amounts of data. Besides, different database codepages and operating systems have to be considered when moving data in and out of a database.
Such problems can be avoided by using the LOAD utility's FROM CURSOR option. When specifying the FROM CURSOR option, the LOAD utility directly references the result set of a SQL query as the source of a data load operation, thus bypassing the need to produce a temporary data exchange file. This way, a LOAD FROM CURSOR is a fast and easy possibility to move data between different tablespaces or different databases. LOAD FROM CURSOR operations can be executed on the command line as well as from within an application or a stored procedure by utilizing DB2's ADMIN_CMD stored procedure. This article introduces the LOAD FROM CURSOR feature and provides usage samples for both interfaces, the DB2 Command Line Processor (CLP) and ADMIN_CMD stored procedure.

使用 DB2 LOAD 实用程序的 FROM CURSOR 选项简化 DB2® for Linux®, UNIX®, and Windows® 的数据转移过程。本文介绍 LOAD FROM CURSOR 特性并提供两个接口 Command Line Processor 和 ADMIN_CMD 存储过程的使用示例。

简介

典型的 DB2 数据转移任务涉及三个步骤：

把数据以二进制或文本格式从源数据库导出到一个临时数据交换文件
在系统之间转移生成的文件
把数据从文件导入或装载到目标数据库中
在数据量很大的情况下，使用 EXPORT 实用程序生成数据交换文件常常要花费很长时间。另外，在把数据移入和移出数据库时，必须考虑不同的数据库编码页和操作系统。

可以使用 LOAD 实用程序的 FROM CURSOR 选项避免这些问题。当指定 FROM CURSOR 选项时，LOAD 实用程序直接把一个 SQL 查询的结果集作为数据装载操作的来源，这样就不需要生成临时数据交换文件。因此，LOAD FROM CURSOR 是在不同的表空间或数据库之间快速轻松地转移数据的方法。可以在命令行上执行 LOAD FROM CURSOR，也可以通过使用 DB2 的 ADMIN_CMD 存储过程在应用程序或存储过程中执行它。本文介绍 LOAD FROM CURSOR 特性并提供两个接口 Command Line Processor (CLP) 和 ADMIN_CMD 存储过程的使用示例。