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Learn how to manage identity fields in GraphQL SPQR and prevent them from being marked as Not Null during creates, while still retrieving them later.
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Handling Identity Fields in GraphQL SPQR: A Comprehensive Guide

When working with databases in applications powered by GraphQL, particularly with frameworks like SPQR, you might encounter challenges regarding identity fields. Specifically, if you're using a database column that auto-generates its value (like a trade ID), you may be faced with an issue: the schema generated by SPQR may treat this field as Not Null, which complicates the data creation process since you won't have that ID before the record is created.

In this guide, we’ll explore the problem and provide multiple solutions to handle identity fields effectively in GraphQL SPQR.

The Problem at Hand

Let's break down the problem. You have a field in your entity that is defined as follows:

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The key issues you might face include:

Not Having the ID On Create: When you try to create a new record, the tradeId will not yet exist because it's generated by the database.

SPQR Schema Generation: The GraphQL schema generated using SPQR flags tradeId as Not Null, causing problems when you try to send a create request without it.

Solutions for Handling Identity Fields

To address this problem, you have a few options. They revolve around changing the way you define the tradeId field so that it's no longer forced to be Not Null. Let’s break this down into specific approaches:

1. Change to an ID Scalar Type

One effective solution is to turn the tradeId into a scalar type:

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

Benefits: By using @ GraphQLId, you're explicitly stating that this field represents an identity that is automatically generated. GraphQL will properly handle the nullable aspect for you.

2. Assign a Default Value

Another approach is to provide a default value for the field when it's used as input in GraphQL:

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

Benefits: This way, the system assigns a default value which satisfies the Not Null constraint, enabling the create operations to go through without the explicit ID.

3. Use Integer Instead of int

Alternatively, you can redefine the field as Integer rather than int:

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

Benefits: The Integer wrapper class can be null, thereby allowing your GraphQL schema to accept the absence of a value during creation. This makes it more flexible for the scenarios you are encountering.

Conclusion

Handling identity fields in GraphQL SPQR doesn’t have to be a headache. By redefining your entity's structure through the use of ID scalar types, default values, or by switching to nullable types, you can seamlessly manage both the creation of new records and their retrieval later on.

Embracing these techniques ensures you can leverage the power of GraphQL while effectively managing the fields that your database generates automatically, leading to a smoother development experience.

Implement these strategies in your projects and watch your GraphQL API become more robust and adaptable to changing needs.