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Talend Open Studio Cookbook

You're reading from  Talend Open Studio Cookbook

Product type Book
Published in Oct 2013
Publisher Packt
ISBN-13 9781782167266
Pages 270 pages
Edition 1st Edition
Languages
Author (1):
Rick Barton Rick Barton
Profile icon Rick Barton
Toc

Table of Contents (21) Chapters close

Talend Open Studio Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
1. Introduction and General Principles 2. Metadata and Schemas 3. Validating Data 4. Mapping Data 5. Using Java in Talend 6. Managing Context Variables 7. Working with Databases 8. Managing Files 9. Working with XML, Queues, and Web Services 10. Debugging, Logging, and Testing 11. Deploying and Scheduling Talend Code 12. Common Mistakes and Other Useful Hints and Tips Common Type Conversions
Management of Contexts Index

Rewritable lookups using an in-process database


The tHash components are great for storing intermediate data in memory and are very efficient, but do not allow updates. Database tables allow updates, but aren't as efficient when writing and reading data on a row-by-row basis, especially when there are large numbers of rows to be processed.

This recipe shows how we can get the best of both worlds using a feature of the HSQL database that allows us to define databases that only reside in memory for the given process.

Due to this job being fairly complex, there are a few techniques used that can be found in other chapters of the book, but aren't explained in detail in this chapter. In addition, it will aid understanding if we provide a background for this scenario.

Background

In this recipe we are presented with a list of customers with their countries of residence. We wish to cross-reference their residence country with our list of countries held in our MySQL database and:

  • if the country is found...

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