Lazy Loading vs Eager Loading vs Explicit Loading in EF Core: Which One Should You Use?

When working with Entity Framework Core, loading related data efficiently is just as important as writing correct queries.

EF Core provides three approaches:

• Eager Loading
• Lazy Loading
• Explicit Loading

Each has its own strengths and trade-offs.

Choosing the wrong one can lead to unnecessary database calls and poor application performance.

Let’s explore when to use each.

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1. Eager Loading

Eager loading retrieves the main entity and its related data in a single query using Include().

Example:

var orders = await context.Orders
    .Include(o => o.Customer)
    .ToListAsync();

Here, both Orders and their related Customer data are loaded together.

Use Eager Loading When:

• You know you’ll need the related data.
• You want to minimize database round trips.
• You’re building APIs that return complete object graphs.

Pros

• Fewer database queries.
• Better performance in many scenarios.
• Easy to understand.

Cons

• Can retrieve unnecessary data if overused.
• Multiple Include() calls may produce complex SQL queries.

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2. Lazy Loading

With lazy loading, related data isn’t loaded until it’s actually accessed.

Example:

var order = await context.Orders.FirstAsync();

var customer = order.Customer;

The second line triggers another database query.

Use Lazy Loading When:

• Related data is rarely needed.
• Simplicity is more important than maximum performance.

Pros

• Loads data only when needed.
• Cleaner code.

Cons

• Can generate many hidden database queries.
• May lead to the N+1 query problem.
• Less predictable performance.

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3. Explicit Loading

Explicit loading gives you full control over when related data is retrieved.

Example:

var order = await context.Orders.FirstAsync();

await context.Entry(order)
    .Reference(o => o.Customer)
    .LoadAsync();

The related entity is loaded only when you explicitly request it.

Use Explicit Loading When:

• You only need related data in specific scenarios.
• You want predictable database access.
• You’re optimizing performance-critical code.

Pros

• Full control over database queries.
• Avoids unnecessary loading.

Cons

• Requires additional code.
• Easier to forget loading related entities.

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Beware of the N+1 Query Problem

Consider this:

var orders = await context.Orders.ToListAsync();

foreach (var order in orders)
{
    Console.WriteLine(order.Customer.Name);
}

If lazy loading is enabled, EF Core may execute:

• 1 query for all orders.
• 1 additional query for each customer.

If there are 100 orders, that could result in 101 database queries.

This is known as the N+1 query problem, and it can significantly impact performance.

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Which One Should You Choose?

Scenario	Recommended
You already know you’ll need related data	✅ Eager Loading
Related data is optional and rarely used	✅ Lazy Loading
You need precise control over when data is loaded	✅ Explicit Loading

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Final Thoughts

There isn’t a single “best” loading strategy.

The right choice depends on your application’s requirements.

My general rule is:

• Prefer Eager Loading for APIs and common queries.
• Use Explicit Loading when you need fine-grained control.
• Use Lazy Loading carefully, especially in high-performance applications, to avoid hidden database queries.

Understanding these loading strategies can help you build faster, more efficient EF Core applications.