How Can I Efficiently Filter Data Using Include in EF Core 5?

Optimizing Data Retrieval in EF Core 5 using Filtered Includes

Entity Framework Core 5 enhances data loading efficiency with filtered Include statements. This allows for selective data retrieval during the initial query, minimizing unnecessary data transfer.

Functionality

Several filter operations are supported within Include statements:

• Where
• OrderBy/OrderByDescending
• ThenBy/ThenByDescending
• Skip
• Take

Illustrative Example

This example demonstrates filtering posts based on the author while eagerly loading them:

<code class="language-csharp">using (var context = new BloggingContext())
{
    var blogs = context.Blogs
        .Include(blog => blog.Posts.Where(post => post.Author == "me"))
        .ToList();
}</code>

Key Considerations

• Each navigation property allows only one filter.
• Filtered collections are marked as loaded, regardless of lazy loading configuration.
• Multiple filtered Include statements accumulate results.
• The filter expression must be a self-contained predicate for the collection.

Relationship Management

EF Core's change tracking might add extra data to the collection due to relationship fixup.

Comparison: Filtered Include vs. Query Filtering

Filtered Include doesn't affect the main query's result count. Use a Where clause on the main query to filter the overall results.

Interaction with Projections

Projections generally disregard Include statements. However, an Include will be applied if the projection includes an entity to which it's relevant.

By understanding these points, developers can effectively utilize filtered Include to efficiently load and filter data simultaneously.

The above is the detailed content of How Can I Efficiently Filter Data Using Include in EF Core 5?. For more information, please follow other related articles on the PHP Chinese website!