What is the purpose of the Include() method in EF?

Question

Ravi Vishwakarma · Answer

The Include() method in Entity Framework is used for eager loading related entities — it tells EF to
load associated data along with the main entity in a single query.
Why Use Include()?
By default, Entity Framework uses lazy loading (if enabled), which means related entities are loaded
only when accessed — often resulting in N+1 queries.
Using Include():
Reduces round-trips to the databaseImproves performance for related dataLoads navigation properties upfront (eagerly)
Example Scenario
Imagine you have two entities:
public class Order
{
    public int Id { get; set; }
    public Customer Customer { get; set; }
    public ICollectionandlt;OrderItemandgt; Items { get; set; }
}
public class OrderItem
{
    public int Id { get; set; }
    public string Product { get; set; }
}
Without Include():
var orders = context.Orders.ToList();
// accessing order.Items will cause separate queries (lazy loading)
With Include():
var orders = context.Orders
    .Include(o =andgt; o.Items)
    .ToList(); // Loads Orders + related Items in 1 query
Multiple Levels of Include (Nested Navigation)
var orders = context.Orders
    .Include(o =andgt; o.Customer)
    .Include(o =andgt; o.Items)
    .ToList();
Deep Include (EF Core Only)
.Include(o =andgt; o.Items.Select(i =andgt; i.Product))
In EF6, for multi-level include, you use ThenInclude() in EF Core or string-based paths in EF6:
.Include("Items.Product") // EF6
Notes
Behavior
Details
Eager Loading
Loads related data immediately via Include()
Lazy Loading
Loads related data on first access (must be enabled)
Explicit Loading
You load related data manually using Load()
Summary
Feature
Include() Method
Purpose
Eagerly load related entities
Helps avoid
Lazy loading performance issues
Common use cases
Parent-child relationships (e.g., Orders + Items)
EF versions
Available in EF6 and EF Core

Behavior	Details
Eager Loading	Loads related data immediately via `Include()`
Lazy Loading	Loads related data on first access (must be enabled)
Explicit Loading	You load related data manually using `Load()`

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What is the purpose of the Include() method in EF?

Ravi Vishwakarma

Can you answer this question?

1 Answers

Why Use `Include()`?

Example Scenario

Without `Include()`:

With `Include()`:

Multiple Levels of Include (Nested Navigation)

Deep Include (EF Core Only)

Notes

Summary

Liked By

Feature	`Include()` Method
Purpose	Eagerly load related entities
Helps avoid	Lazy loading performance issues
Common use cases	Parent-child relationships (e.g., Orders + Items)
EF versions	Available in EF6 and EF Core