IBM 000-8697 ユーザーズマニュアル

IBM Informix OnLine Database Server Administrator’s Guide

The tbunload utility can unload data more quickly than either dbexport or
the

UNLOAD

command because it copies the data in binary and in page-sized

units. However, this places some constraints on its use:

■

 writes data to tape only.

■

You must load the tape written by tbunload onto a machine with the
same page size as the original machine.

■

You must load the data on the tbunload tape into a database or table
managed by OnLine.

■

When you unload a complete database, ownership of all database
objects (such as tables, indexes, and views) cannot be modified until
after the database is unloaded.

■

 unloads page images. If you load the pages to another

machine that stores numeric data types differently than your current
machine (for example, with the most significant byte last instead of
first), the contents of the data page could be misinterpreted.

■

 does not carry over access privileges or synonyms that

were defined on the original tables.

The tbload utility performs faster than the dbimport, dbload, or

LOAD

options. In exchange for this higher performance, the following five
constraints exist:

■

 can only create a new database or table; you must drop or

rename an existing database or table of the same name before tbload
is run. (tbload prompts you to rename blobspaces during execution,
if desired.)

■

 locks the database or table exclusively during the load.

■

When you load a complete database, the user executing tbload
becomes the owner of the database.