Скачать или смотреть How to Use XSLT 1.0 to Group XML Nodes by Child Values

Discover how to use `XSLT 1.0` for effective XML transformation by grouping nodes based on child values while eliminating duplicates.
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Grouping XML Nodes by the Value of a Child Element Using XSLT 1.0

Working with XML can sometimes feel like navigating a stormy sea. Whether you're dealing with complex data structures or simply trying to clean up redundant entries, transforming XML efficiently is crucial—especially when you're limited to XSLT 1.0. In this guide, we'll explore how to group XML nodes by the value of a child element, all while preserving the integrity of your data structure.

The Problem

Let's start by defining the scenario. You have a collection of XML nodes with the following structure:

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Here’s what you need:

Group nodes according to the unique Order value.

Preserve the order of A and B nodes.

Eliminate duplicate Order nodes.

Maintain a clear output structure.

Given the input, the desired output structure looks like this:

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The task at hand is to achieve this transformation using XSLT 1.0.

The Solution

To tackle this problem, we can utilize the Muenchian Grouping Method in XSLT. This approach allows us to group nodes based on their corresponding values efficiently. Here’s how we can implement the solution in a step-by-step manner.

Step 1: Define the XSLT Stylesheet

We start by defining the basic structure of the XSLT stylesheet, specifying the input and output parameters, which is essential for our transformation.

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Step 2: Create the Key for Grouping

Next, we create a key to facilitate the grouping of Message nodes by their Order values:

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Step 3: Identity Template

To ensure we copy all nodes by default, we incorporate an identity transform. This serves as the backbone of our transformation process:

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Step 4: Grouping Logic

The critical part is the logic for grouping the Order nodes. We want to copy the Order along with its corresponding Article nodes efficiently:

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Step 5: Exclude Articles

To prevent duplication of the Article nodes, we create a template that matches Message[Article] and simply does nothing:

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Complete XSLT Code

Combining all the steps, your complete XSLT code will look like this:

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Conclusion

By following these steps, you can effectively group XML nodes using XSLT 1.0 while preserving the necessary hierarchy and avoiding duplicate entries. Whether you're implementing this in a BizTalk mapping or another application, this approach is a robust solution to handle XML transformations.

Happy coding, and may your XML transformations be smooth and efficient!