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You're reading from  Web API Development with ASP.NET Core 8

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Published inApr 2024
PublisherPackt
ISBN-139781804610954
Edition1st Edition
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Xiaodi Yan
Xiaodi Yan
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Xiaodi Yan

Xiaodi Yan is a seasoned software engineer with a proven track record in the IT industry. Since 2015, he has been awarded Microsoft MVP, showcasing his dedication to and expertise in .NET, AI, DevOps, and cloud computing. He is also a Microsoft Certified Trainer (MCT), Azure Solutions Architect Expert, and LinkedIn Learning instructor. Xiaodi often presents at conferences and user groups, leveraging his extensive experience to engage and inspire audiences. Based in Wellington, New Zealand, he spearheads the Wellington .NET User Group, fostering a vibrant community of like-minded professionals. Connect with Xiaodi on LinkedIn to stay updated on his latest insights.
Read more about Xiaodi Yan

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Using variables in queries

In the previous section, we learned how to query data and modify data using GraphQL queries and mutations. In this section, we will discuss how to use variables in queries.

GraphQL allows you to use variables in queries. This is useful when you want to pass parameters to the query. We can create a query that accepts an id parameter and returns the teacher with the specified ID. Follow these steps to create the query:

  1. Add a GetTeacher() method in the Query class, as follows:
    public async Task<Teacher?> GetTeacher(Guid id, [Service] AppDbContext context) =>    await context.Teachers.FindAsync(id);

    The preceding code adds a GetTeacher() method to the Query class. It takes an id parameter and returns the teacher with the specified ID.

  2. Now, you can use the $ sign to define a variable in the query. For example, you can use the following query to get a teacher by ID:
    query getTeacher($id: UUID!) {  teacher(id: $id...
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Web API Development with ASP.NET Core 8
Published in: Apr 2024Publisher: PacktISBN-13: 9781804610954

Author (1)

author image
Xiaodi Yan

Xiaodi Yan is a seasoned software engineer with a proven track record in the IT industry. Since 2015, he has been awarded Microsoft MVP, showcasing his dedication to and expertise in .NET, AI, DevOps, and cloud computing. He is also a Microsoft Certified Trainer (MCT), Azure Solutions Architect Expert, and LinkedIn Learning instructor. Xiaodi often presents at conferences and user groups, leveraging his extensive experience to engage and inspire audiences. Based in Wellington, New Zealand, he spearheads the Wellington .NET User Group, fostering a vibrant community of like-minded professionals. Connect with Xiaodi on LinkedIn to stay updated on his latest insights.
Read more about Xiaodi Yan