Services
Technology Web App Development Mobile App Development Windows App Development Database Development UI/UX Development Cloud Development SEO Digital Marketing Guest Posting Content Writing Artificial Intelligence Data Science ERP Development CRM Development CMS Development LMS Development Business Listing Blockchain Technology Startup Promotion AI Tools Integration
Products
Data Converter Cleaner TUC - Unit Converter Import Export Survey Manager Tweet Controller
Developer
Article Blog Forum Interview Beginner News Startup Quiz
Users
Career
Apply Job Internship
Pricing
Login Sign Up Get a Quote

interview

Home Interviews What is the purpose of the Include() method in EF? – MindStick
Ask Question

1 Answers

ICSM Computer
ICSM Computer 13 Jun 2025
Report Abuse

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 database
  • Improves performance for related data
  • Loads 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 ICollection<OrderItem> 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 => o.Items)
    .ToList(); // Loads Orders + related Items in 1 query

Multiple Levels of Include (Nested Navigation)

var orders = context.Orders
    .Include(o => o.Customer)
    .Include(o => o.Items)
    .ToList();

Deep Include (EF Core Only)

.Include(o => o.Items.Select(i => 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
MindStick Training
Markdown for AI

A clean, structured version of this page for AI assistants and LLMs.

Open .md