Choosing Data-Migration Tools

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Choosing Data-Migration Tools

This section provides brief descriptions of the tools, utilities, and SQL statements that you can use to move data from one database to another.

When you migrate to the current version of the database server, you can use these data-migration tools:

The onunload and onload utilities (only between database servers of the same version)
The dbexport and dbimport utilities
UNLOAD and LOAD statements and the dbload utility
The dbschema utility
The High-Performance Loader (HPL)
Nonlogging raw tables

For more information about the utilities and statements listed above, see the chapters in the last section of this guide.

In some previous versions of the database server, you could use IBM Informix Enterprise Command Center (IECC) to move data from one database to another.

If you need to migrate to another version of Dynamic Server before you migrate to Version 10.0 and you want information on the migration tools and utilities that can be used for migration to an intermediary version of Dynamic Server, see the Migration Guide that is included in the documentation set for that database server.

The table below contains a list of the tools you can use for each IBM Informix database server. An asterisk (*) after the utility name identifies a tool that was used in a previous version of Dynamic Server, but is no longer used.

Table 13. Utilities for Moving Data
Utility	IDS 10.0	IDS 9.40 and 9.30	IDS 7.3x or 7.24	SE 7.2x and 5.1x	OL 5.1x
dbexport/ dbimport	x	x	x	x	x
dbload	x	x	x	x	x
HPL	x	x	x
onunload/ onload	x	x	x
UNLOAD/ LOAD	x	x	x	x	x
IECC*			x

The best method for moving data depends on your operating system and whether you want to move an entire database, selected tables, or selected columns from a table. The table below summarizes the characteristics of the methods for loading data and the constraints and advantages of each method.

Table 14. Comparison of Tools for Loading Data
Utility	dbexport/ dbimport	dbload	HPL	onunload/ onload	UNLOAD/ LOAD
Granularity of Data	Database only	Partial or complete table	Partial or com-plete table	Table or database	Partial or complete table
Performance	Moderate	Slow	Fast	Fast	Moderate
Source of Data	Usually prod-uced by dbexport	Any data in the format specified by the input file	Any ASCII or COBOL data. User can create custom read capabilities.	Must be prod-uced by on-unload	Any data in the specified format, usually produced by UNLOAD
Database Schema	Can modify	Can modify	Can modify	Cannot modify	Can modify
Location of Data	Disk or tape	Disk only	Disk, tape, or pipe	Disk or tape	Disk only
Type of File	Text	Text	Text	Binary	Text
Logging Status	Logging optional	Logging optional	Logging optional	Logging must be turned off	Logging optional
Move Data Between Operating Systems?	Yes	Yes	Yes, or from a non-Infor-mix data-base	No	Yes
Ease of Use	Moderate	Moderate	Most difficult	More difficult	Easiest

The following sections provide guidelines on how to choose the appropriate migration tool or tools.