Solving the missing field registration_key Error in Rust with SQLx

Описание: Learn how to handle the `missing field registration_key` error when accessing your Rust struct using SQLx. This guide provides a detailed breakdown of the solution.
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This video is based on the question https://stackoverflow.com/q/76852201/ asked by the user 'Mickers' ( https://stackoverflow.com/u/4611543/ ) and on the answer https://stackoverflow.com/a/76853146/ provided by the user 'DrLarck' ( https://stackoverflow.com/u/10566644/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: missing field `registration_key` in initializer of `database::models::RegistrationKeys`

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The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

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Addressing the missing field registration_key Error in Rust SQLx

When working with Rust and SQLx, you might encounter a frustrating error that says, "missing field registration_key in initializer of database::models::RegistrationKeys." This issue occurs when your code tries to retrieve data from the database without properly matching the struct definition you’ve created. In this post, we'll walk through the problem and provide a clear solution step by step.

Understanding the Problem

The source of the error lies in the way you've defined your RegistrationKeys struct and how you're querying the database. Your struct is defined as follows:

[[See Video to Reveal this Text or Code Snippet]]

So, your struct expects both an id and a registration_key. However, when you perform the database query, you're only selecting the id field:

[[See Video to Reveal this Text or Code Snippet]]

This results in an incomplete initialization of the RegistrationKeys struct because it's missing the registration_key value, hence the error message.

The Solution

To resolve this issue, you need to update your SQL query so that it returns both the id and the registration_key. Here’s how you can do that.

Update Your SQL Query

Modify your SQL query to include the registration_key field in the selection. Here’s the corrected version:

[[See Video to Reveal this Text or Code Snippet]]

Final Code Example

Here’s how your complete code snippet should look after making the changes:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code

String::from("ABCD"): This line initializes a string variable that holds the registration key you are looking for.

query_as!: This macro allows you to perform a SQL query and automatically map the result to your struct.

fetch_one(&pool): This method fetches a single record from the database.

By ensuring that both expected fields (id and registration_key) are selected, your struct will properly initialize, and the error will be resolved.

Conclusion

Encountering errors when working with databases and programming languages is a common challenge. However, with the right approach and understanding of how data is structured, you can effectively tackle these issues. By updating your SQL query to retrieve all the necessary fields, you ensure your Rust struct is initialized correctly and avoid the missing field registration_key error.

We hope this guide has helped clarify the issue and provided you with a solution! Happy coding!