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Chapter 13. The onunload and onload utilities
The onunload and onload utilities provide the fastest way to move data between
computers that use the same database server on the same platform.
For example, your site purchases a more powerful UNIX computer to allow faster
access for users. You need to transfer existing databases to the new database server
on the new computer. Use onunload to unload data from the first database server
and then use onload to load the data into the second database server. Both
database servers must have the same version number, or they must have
compatible version numbers. You can move an entire database or selected tables
only, but you cannot modify the database schema.
The onunload utility can unload data more quickly than either dbexport or the
UNLOAD statement because onunload copies the data in binary format and in
page-sized units. The onload utility takes a tape or a file that the onunload utility
creates and re-creates the database or the table.
The onunload and onload utilities are faster than dbimport, dbload, or LOAD but
are much less flexible and do not let you modify the database schema or move
from one operating system or database server version to another.
Important: You can use the onunload and onload utilities with Dynamic Server
11.10, 10.00, 9.40, 9.30, or 9.21 if the databases contain only legacy data types and
no extended data types. In addition, you cannot use these utilities with Dynamic
Server versions that are earlier than version 7.24.
Related concepts
“Choosing a tool for moving data before migrating between operating systems” on
page 8-1
Related reference
“Data-migration tools” on page 2-1
Guidelines for when to use the onunload and onload utilities
You can use onunload and onload only when certain conditions are met.
You can use only onunload and onload if your answer to each of the following
questions is yes. If your answer is no, you cannot use onunload and onload.
Use onunload and onload Only If Your Answer To Each Question Is Yes
Is the target database server on the same hardware platform?
Do you want to move to another database server of the same version?
Do you want to keep the existing database schema without modifying it?
Do you want to move an entire database or an entire table?
Are the page images compatible?
Are the numeric representations the same?
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