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The Definitive Guide to Power Query (M)

You're reading from   The Definitive Guide to Power Query (M) Mastering complex data transformation with Power Query

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Product type Paperback
Published in Mar 2024
Publisher Packt
ISBN-13 9781835089729
Length 758 pages
Edition 1st Edition
Languages
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Authors (3):
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Greg Deckler Greg Deckler
Author Profile Icon Greg Deckler
Greg Deckler
Melissa de Korte Melissa de Korte
Author Profile Icon Melissa de Korte
Melissa de Korte
Rick de Groot Rick de Groot
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Rick de Groot
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Toc

Table of Contents (19) Chapters Close

Preface 1. Introducing M FREE CHAPTER 2. Working with Power Query/M 3. Accessing and Combining Data 4. Understanding Values and Expressions 5. Understanding Data Types 6. Structured Values 7. Conceptualizing M 8. Working with Nested Structures 9. Parameters and Custom Functions 10. Dealing with Dates, Times, and Durations 11. Comparers, Replacers, Combiners, and Splitters 12. Handling Errors and Debugging 13. Iteration and Recursion 14. Troublesome Data Patterns 15. Optimizing Performance 16. Enabling Extensions 17. Other Books You May Enjoy
18. Index

Raising errors

In Power Query’s M language, you can define custom errors. This is helpful when you want to provide more specific and meaningful error messages, be able to handle exceptional cases, enforce custom data validation rules, or improve the overall user experience for example.

The error expression

To raise an error, simply call the error-raising expression error and use a text value to provide the desired error message you want to display. For example, this expression will raise the following error:

error "Invalid data, you did not provide a table."

Errors provide an error record; therefore, you can also specify a record to include more information about the error. This error record should contain fields such as Reason, Message, and Detail. Here’s an example of how to raise an error with a custom error record:

error [
    Reason = "Invalid data, you did not provide a table.",
    Message = "The data provided is not...
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