Никто не встречал документацию по переходу с Oracle на Informix, наподобие Oracle Migration Workbench Reference Guide for IDS Migrations?

Из русского отделения IBM получил 3 документа:
1. Porting Applications from Oracle to Informix. A Discussion of the Application Porting Issues. Version 3.3. Glen Black & Frank Martino
Partner Engineering Organization,
Informix Software Incorporated - November 6, 1997
2. То же самое, только версии 6.0 от 30 мая 2000 года.
3. Oracle to Informix Migration Docment
Приведу этот документ полностью, может, пригодится кому:

Introduction

This document describes the basic steps required to migrate from an Oracle 8i database to an Informix IDS.2000 server. It is intended as an overview to be used to decide upon viability, it is not a manual for migration. Detailing application changes and assigning timescales are not considered to be within the scope of this document.

The document will be divided into two sections, the first will discuss some of the changes required when migrating between the database products. The second will outline a suggested plan of events to facilitate migration.

Overview of Changes Required

This section deals with the basic changes required to enable an Oracle database to be ported to an Informix environment. It is divided into the 3 key areas of change: Data Definition Language, Data Manipulation Language and briefly Application.
Data Definition Language
Generally the DDL of both databases is very similar, the differences are mainly syntactic. The schema for the Oracle database would need to be edited to ensure it is valid Informix syntax. The key areas of change are:

- Identifiers, ensure all identfiers in Oracle schema are valid within Informix. Keywords in Informix will need to be delimited with quotes. Some characters cannot be used to start identifier names these should be removed.

- Databases, the organisation of tables in databases may need to be modified as Informix can support many databases within a single instance (server).

- Data storage, Oracle tables are stored in tablespaces the Informix eqivalent are dbspaces. The number required would need to be decided at the initial planning stage.

- Table definitions, tables should be sized to enable extent and next extent sizes to be calculated. This is recommended as the sizes decided originally could now be out of date. The synatx for extent size allocation is different for Informix. Oracle also implements partitioning, the Informix equivalent is fragmentation. Again the strategy for fragmention should be planned in advance.

- Data types, some Oracle data types do not map exactly to Informix types. Some investigation will be required to determine individual columns new data types. E.g. Oracle has a single NUMBER data type to store numeric values, Informix has several different numeric types. The type of number being stored will determine which of the Informix data types are to be used. The same applies to CHARs, VARCHARs, DATEs and binary data types. Note data type changes may require application host variable definitions to be changed.

- User defined types, both products support these. Migration to Informix requires only some syntatic changes.

- Indexes, the limits of Informix indices differ to those in Oracle and in some extreme cases they may need to be rewritten.

- Triggers, conversion of triggers are straigtforward.

- Stored Procedures, depending on the complexity of the procedures this should be quite straightforward.
Data Manipulation Language

This sections covers changes required to the Oracle data manipulation language to comply with Informix’s. This will include changes to the SQL syntax, and supporting built in functions and facilities that are specific to Oracle. The areas covered in this section will to overlap with application changes, as most applications will use embedded SQL. Note all exisiting SQL statements will need to be tested on the Informix server irrespective of any changes to ensure they run as expected. The key areas for change are:

- SQL, some of the oracle syntax includes labels that are reserved words in Informix these would need minor amendments. Optimiser hints should be removed, as the Informix optimiser is totally different rendering the hints irrelevant. There would also be modifications to the syntax of some commands.

- Functions, many of the Oracle funtions are now supported by Informix, those that are not can be emulated using user definied routines. Care should be taken to ensure that the behaviour of the Informix equivalent functions do not adversly effect applications. Oracle’s system date and time functions can be replicated using Informix equivalents

- Other issues exist where functionality is not matched, these can be resolved by application changes or writing user defined routines.
Application

This section is small, as it is beyond the scope of this document to discuss all possible changes to applications. Instead is outlines the areas where changes will be required. However when using 3rd party products it is recommended to use a product specifically ported for Informix. It should also be noted that changes to application code to convert from Oracle to Informix are non-trivial. The following areas would need to be looked at when converting applications.

- Connectivity, if Oracle OCI is used this will need to be rewritten to use the Informix CLI

- Modification of embedded SQL structure and constructs

- Modification of SQL syntax where Oracle specific code is used

- Changes to host variables and record structures

- Modify transaction-processing method.

- Create all Oracle users as Informix users. ( different approach to security and access )


Suggested Plan

Using the information discussed above this section outlines the tasks required when migrating from Oracle to Informix. I have deliberately omitted application changes, as this could be a project in it’s own right. The time taken will be dependent on the schema complexity. Factors affecting complexity include number of tables and variety of data types, amount of partitioning, numbers of triggers and stored procedures and number of extra user defined routines to be written.

Once the table structures and sizes are known some time should be spent planning the organisation of the Informix instance. This will include the sizing of initial extents and the physical location of the table’s data. Tuning of the configuration for performance can be done at a later date.

As with all these types of project it is extremely important to ensure that nothing is missed in the migration process and that the data does not lose it’s integrity in the move. To avoid these issues a detailed checklist can be provided to highlight the tasks required. This checklist can be used in conjuction with the schema to build a project plan with estimates of time. It would also be a good idea to write an SQL script that produced a series of checks and balances on every table. This could be run on both systems to prove that the information has been copied succesfully.

The list below contains a high level list of the tasks required to migrate, it is far from complete and is just a guide as to the overall process, not the how. There are many issues to be resolved before a proper plan could be put together.

Tasks

Prerequesites

- Create schema of existing Oracle database(s)
- Create a plan of conversion tasks based on schema contents
- Decide on the data layout for the Informix version
Including: numbers and location of Dbspaces, Blobspaces, Initial and Next Extent sizes per table
- Create a data validation script to run on Oracle and Informix to ensure all data has been migrated succesfully
- Unload tables for migration as flat data files
- Put database in single user mode, and run data validation scripts
- Decide on a format for numbers and dates


Create Informix DDL
Using Oracle schema, including changes to the following

- Identifiers
- Databases
- Tables
Including: Constaints, Fragmentation, Extent sizes
- Data Types
- Sequences
- Indexes
- Views
- Rewrite / modify Stored Procedures and Triggers
- Remove non-supported Oracle extensions from DDL


Data Manipulation Language Changes
These will generally be changes to scripts and stored procedures that execute SQL.

- SQL
- Host Variables
- Convert fnctions where required
- Macros
- Pseudo-Columns
- Modify update Using Cursors
- Convert System table references
- DUAL Table

Create Database on Informix

- Create new instance, and dbspace structure
- Run new DDL script
- Load data from unload files
- Run update statistics
- Create all Oracle users as UNIX users
- Run data validation scripts
- Run all available SQL scripts to check performance