Book Image

Talend Open Studio Cookbook

By : Rick Barton
Book Image

Talend Open Studio Cookbook

By: Rick Barton

Overview of this book

Data integration is a key component of an organization's technical strategy, yet historically the tools have been very expensive. Talend Open Studio is the world's leading open source data integration product and has played a huge part in making open source data integration a popular choice for businesses worldwide.This book is a welcome addition to the small but growing library of Talend Open Studio resources. From working with schemas to creating and validating test data, to scheduling your Talend code, you will get acquainted with the various Talend database handling techniques. Each recipe is designed to provide the key learning point in a short, simple and effective manner.This comprehensive guide provides practical exercises that cover all areas of the Talend development lifecycle including development, testing, debugging and deployment. The book delivers design patterns, hints, tips, and advice in a series of short and focused exercises that can be approached as a reference for more seasoned developers or as a series of useful learning tutorials for the beginner.The book covers the basics in terms of schema usage and mappings, along with dedicated sections that will allow you to get more from tMap, files, databases and XML. Geared towards the whole lifecycle, the Talend Open Studio Cookbook shows readers great ways to handle everyday tasks, and provides an insight into all areas of a development cycle including coding, testing, and debugging of code to provide start-to-finish coverage of the product.
Table of Contents (21 chapters)
Talend Open Studio Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Common Type Conversions
Index

Using context and globalMap variables in SQL queries


It is possible to use parameters passed or created in a job to drive the results of a SQL query. This short recipe shows how.

Getting ready

Open the job jo_cook_ch07_0020_contextInQuery, which is a copy of the job from the previous recipe.

How to do it…

The steps to be performed are as follows:

  1. Open the tMysqlInput component.

  2. Change the final line to HAVING SUM(o.`orderTotal`) > "+context.minOrderValue.

  3. Run the job and you will be prompted for a value.

  4. Enter 10 and click on Ok.

  5. You should see that the result set contains orders where the sum of the lines is > 10.

How it works…

The SQL statement used by tMysqlInput is held in a string, so can be manipulated just as any other string in Java. Thus, we can alter the value of the string using normal Java conventions; in this case a concatenate (+).

The statement is thus translated at runtime and the value of the context substituted into the SQL query, which returns the customized resultset.

There...