Mastering Entity Framework Core: Best Practices for .NET Developers — A Beginner’s Guide

Unleash the Power of Data Access Technology with a Pinch of Humor

Hold on to your hats, folks! You’re about to dive headfirst into the world of Entity Framework Core, Microsoft’s data access technology that’s as cool as a cucumber. In this beginner’s guide, we’ll cover the best practices for .NET developers who want to make friends with EF Core. You’ll learn about navigation properties, related entities, and all sorts of loading techniques. And, of course, we’ll touch on LINQ queries, query execution, and more. So, buckle up, and let’s get this party started!

Entities, Navigation Properties, and Related Entities

In the realm of Entity Framework Core, entities are like little digital minions. They represent your data in code and work tirelessly to help you manipulate it. Navigation properties are the BFFs (best friends forever) of these entities, allowing them to navigate their relationships with other entities (aka related entities).

For example, imagine a “Customer” entity has a navigation property “Orders” that leads to a collection of “Order” entities. You’ve just made a connection between customers and their orders. Isn’t that sweet?

public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }
    public ICollection<Order> Orders { get; set; }
}

public class Order
{
    public int Id { get; set; }
    public string Product { get; set; }
    public Customer Customer { get; set; }
}

Loading Data — Eager, Lazy, and Explicit Loading

Eager loading, lazy loading, and explicit loading are three techniques to load related entities in EF Core. Eager loading grabs all the data you need in a single query. Lazy loading sneaks around in the background, loading data only when you access a navigation property. Explicit loading, on the other hand, makes you work for it by requiring you to request the related data manually.

Eager loading:

var customers = context.Customers.Include(c => c.Orders).ToList();

Lazy loading (using proxies):

var customer = context.Customers.Find(1);
var orders = customer.Orders; // Data is loaded here

Explicit loading:

var customer = context.Customers.Find(1);
context.Entry(customer).Collection(c => c.Orders).Load();

Querying Data — LINQ Queries, Query Execution, and Query Translation

LINQ (Language Integrated Query) is a querying genie that lets you write queries directly in C#. LINQ queries are a way to fetch data from your database, while query execution is the act of actually running the query. Query translation, on the other hand, converts your LINQ query into SQL, the database’s native language.

var customersWithOrders = context.Customers
    .Where(c => c.Orders.Any())
    .ToList(); // Query execution happens here

Query Interception — The Art of Eavesdropping on Queries

Query interception is a stealthy way to monitor or modify queries before they’re executed. With EF Core’s query interception, you can log queries, apply global filters, or even change the queries themselves. To intercept a query, you’ll need to create a custom interceptor class that inherits from DbCommandInterceptor.

public class CustomInterceptor : DbCommandInterceptor
{
    public override InterceptionResult<DbDataReader> ReaderExecuting(
        DbCommand command, CommandEventData eventData, InterceptionResult<DbDataReader> result)
    {
        // Log or modify the query here
        return base.ReaderExecuting(command, eventData, result);
    }
}

Change Tracking — Keeping an Eye on Your Entities

Change tracking is EF Core’s built-in detective that monitors your entities for any changes. Whenever you make changes to your data, change tracking is on the case, keeping track of which entities are added, modified, or deleted. This information is then used when you call SaveChanges() to update the database.

var customer = context.Customers.Find(1);
customer.Name = "New Name"; // Change tracking detects the modification
context.SaveChanges(); // Update the database

Concurrency Control and Transactions — Playing Well with Others

Concurrency control and transactions are essential when multiple users access and modify your data simultaneously. Concurrency control prevents conflicts, while transactions ensure data integrity by grouping multiple operations into a single, atomic unit. EF Core provides built-in support for both, making it easy to maintain data consistency and integrity.

using (var transaction = context.Database.BeginTransaction())
{
    try
    {
        // Perform multiple operations within the transaction
        context.Customers.Add(newCustomer);
        context.Orders.Add(newOrder);
        
        context.SaveChanges();

        // Commit the transaction
        transaction.Commit();
    }
    catch (Exception)
    {
        // Rollback the transaction in case of an error
        transaction.Rollback();
    }
}

Congratulations, dear reader! You’ve reached the end of this funny and simple beginner’s guide to mastering Entity Framework Core. We’ve covered a lot of ground together, from entities and navigation properties to loading techniques, LINQ queries, change tracking, and even concurrency control with transactions.

As you continue your journey as a .NET developer, remember to keep these best practices in mind. They’ll not only help you build efficient and maintainable applications but also make you the life of the party among your developer friends. Now, go forth and conquer the world of data access technology with your newfound Entity Framework Core knowledge! Happy coding!