Tag Archives: File Formats

The Data Mashup Binary Stream: How Power Queries Are Stored

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You create a Power Query and save it. Its written somewhere inside your Microsoft Excel or Microsoft Power BI file—but where and in what format?

First, though, why would understanding the file format used to store Power Queries be of interest? Maybe you’re just curious and like to know how things work. 🙂 Maybe comparing query text between files or hooking up some kind of M version control is important. Maybe you’re looking for automation options, so you can do something like mass update the M code in a folder full of files quickly. While it’s unnecessary to understand the underlying file format to simply use Power Query, there are times and places where knowing about that format can come in handy.

In this post, we’ll lay a foundation on how to get to those saved mashups. We’ll overview the file format used to persist mashups, describing the various pieces of supporting information saved along with them, and point you to where you can learn about the fine, byte-level details of the format (in case you want to write your own parsing logic that reads and even modifies saved M queries!).

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