Скачать или смотреть How to Update an Entity with Related Data in EF Core 3+

This guide explains how to handle updates for entities with related data in Entity Framework Core 3+ , focusing on practical solutions for tracking and efficiently managing these updates.
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How to Update an Entity with Related Data in EF Core 3+

Working with relationships in Entity Framework Core (EF Core) can often lead to some head-scratching moments. One common challenge developers face is updating entities that are intertwined with related data, especially when using the repository pattern. In this post, we’ll tackle the problem of updating an entity with related data arrays—specifically focusing on how to manage updates in EF Core 3+ without running into tracking issues.

Understanding the Context

Let's say you have a complex object structure representing a CV (Curriculum Vitae) that contains Certificates and Experiences as related data.

Simplified Object Structure

Your entity hierarchy might look something like this:

CV: Contains a list of Certificates and Experiences

Certificate: Represents a certification with its unique ID and Name

Experience: Represents job history, potentially with a list of skills

SkillExperience: A join entity for many-to-many relationships between Skills and Experiences

Below is a basic structure of these classes for your context:

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

The Problem of Tracking

When you’re attempting to update a CV which includes its certificates and experiences, you might run into issues related to how EF Core tracks these entities.

You may encounter an exception like this:

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

This error indicates that EF is trying to manage multiple instances of the same entity at once, leading to ambiguity in how updates should be applied.

What Causes This Issue?

This typically occurs because:

Redundant Tracking: You're attempting to manually update a Certificate that is already being tracked by EF after you've included it in your CV entity.

Direct DbSet Access: By directly interacting with your repositories to update entities, you're creating conflicting instances that EF struggles to reconcile.

Solution: Streamlined Entity Updates

To navigate these tracking issues, a change in your approach is essential. Let’s break it down into clear steps:

1. Avoid Manual Updates

Since EF Core already tracks the entities you've loaded with .Include(), you do not need to re-add them or call Update() on them separately. Instead, you can:

Modify the properties on the tracked entity directly.

Let EF Core handle the state management.

When you have a modified entity, simply set the properties you want to change on the existing entity:

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

2. Handling Removed Entities

For entities you need to remove, you can manage this through the IDs you have:

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

3. Managing Many-to-Many Relationships

For complex relationships like experience and skills, a similar pattern applies. You'll need to ensure you're correctly managing the state of entities at both ends of the relationship.

Use navigation properties wisely.

Track existing links, updating, adding, or removing as needed.

Conclusion

Updating entities with related data in EF Core can initially appear daunting, but by leveraging the tracking capabilities of the framework and avoiding unnecessary updates, you can streamline your processes and avoid common pitfalls.

As you continue building your applications, remember that EF Core is designed to handle the complexities of entity relationships - you just need to cooperate with its management of entity states.

If you're looking for tips on more complex updates or if you have specific scenarios you are struggling with, feel free to reach out. Happy coding!