MSDN Documentation

Entity Framework Core vs. EF6

This document provides a detailed comparison between Entity Framework Core (EF Core) and the legacy Entity Framework 6 (EF6), helping you understand their differences, advantages, and use cases.

Introduction

Entity Framework (EF) is a popular Object-Relational Mapper (ORM) for .NET that enables developers to work with databases using .NET objects. Over time, EF has evolved, leading to two major versions:

• Entity Framework 6 (EF6): The last major release of the original EF framework, released in 2013.
• Entity Framework Core (EF Core): A complete rewrite and redesign of Entity Framework, focusing on extensibility, performance, and cross-platform support. It was first released in 2016.

Key Differences

While both frameworks serve the same core purpose, EF Core introduces significant architectural changes and new features. Here's a breakdown of the key differences:

When to Use EF Core

• New Projects: For all new .NET applications, especially those targeting cross-platform or using .NET Core.
• Performance-Critical Applications: EF Core's optimizations often provide better performance.
• Modern Web Applications (ASP.NET Core): Seamless integration with ASP.NET Core and its DI system.
• Cloud-Native Development: Supports modern cloud databases and deployment scenarios.
• Microservices: Its lightweight nature and extensibility make it suitable for microservice architectures.

When to Consider EF6

• Existing .NET Framework Applications: If you have a legacy application running on .NET Framework and upgrading to .NET Core is not feasible in the short term.
• Specific EF6-Only Features: While EF Core is catching up, there might be very niche features or behaviors in EF6 that are critical to your existing application logic.
• Complex ORM Scenarios with Extensive EF6 Tooling: If your team has deep expertise and extensive tooling built around EF6 that would be difficult to migrate.

Code Examples

EF Core - Basic Usage

using Microsoft.EntityFrameworkCore;

public class BloggingContextCore : DbContext
{
    public DbSet<BlogCore> Blogs { get; set; }
    public DbSet<PostCore> Posts { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("Server=(localdb)\\mssqllocaldb;Database=EFCoreDemo;Trusted_Connection=True;");
    }
}

public class BlogCore
{
    public int BlogId { get; set; }
    public string Url { get; set; }
    public virtual ICollection<PostCore> Posts { get; set; }
}

public class PostCore
{
    public int PostId { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }
    public int BlogId { get; set; }
    public virtual BlogCore Blog { get; set; }
}
                

EF6 - Basic Usage

using System.Data.Entity;

public class BloggingContextEF6 : DbContext
{
    public DbSet<BlogEF6> Blogs { get; set; }
    public DbSet<PostEF6> Posts { get; set; }

    public BloggingContextEF6() : base("name=BloggingContextEF6")
    {
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        // EF6 Configuration can go here
        base.OnModelCreating(modelBuilder);
    }
}

public class BlogEF6
{
    public int BlogId { get; set; }
    public string Url { get; set; }
    public virtual ICollection<PostEF6> Posts { get; set; }
}

public class PostEF6
{
    public int PostId { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }
    public int BlogId { get; set; }
    public virtual BlogEF6 Blog { get; set; }
}
                

Conclusion

Entity Framework Core represents the future of data access with .NET. Its cross-platform capabilities, performance enhancements, and modern design make it the recommended choice for new development. EF6 remains a viable option for existing .NET Framework applications, but migration to EF Core should be a strategic consideration for long-term maintainability and access to the latest features.

For detailed migration guides and advanced features, please refer to the official Microsoft documentation for each framework.