MSDN Documentation

Entity Framework Core Overview

Entity Framework Core (EF Core) is a modern, cross-platform, extensible data access technology for .NET. It is a lightweight, high-performance, and open-source version of the popular Entity Framework.

What is Entity Framework Core?

EF Core enables .NET developers to:

• Work with a domain-specific language (DSL) for accessing data.
• Create LINQ queries that are automatically translated into SQL.
• Map .NET objects to relational database tables.
• Manage database schema migrations.
• Handle relationships between entities.
• Perform CRUD (Create, Read, Update, Delete) operations efficiently.

Key Features

EF Core offers a rich set of features designed to simplify data access:

• Object-Relational Mapper (ORM): Maps your .NET objects directly to database tables, abstracting away SQL.
• Cross-Platform: Runs on Windows, macOS, and Linux.
• High Performance: Optimized for speed and memory usage.
• Extensible: Supports custom providers, interceptors, and conventions.
• Model-First, Database-First, and Code-First: Flexible approaches to define your data model.
• Change Tracking: Automatically tracks changes to entities.
• Migrations: Manages database schema evolution over time.
• JSON Columns: Supports storing and querying JSON data.
• Owned Entities: Define complex types that are owned by another entity.
• Value Objects: Model immutable data structures.

Getting Started

To start using EF Core, you typically need to install the appropriate NuGet packages:

dotnet add package Microsoft.EntityFrameworkCore
dotnet add package Microsoft.EntityFrameworkCore.SqlServer  # Or your specific database provider

Then, you define your data model using C# classes and a DbContext:

public class BloggingContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }
    public DbSet<Post> Posts { get; set; }

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

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

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

EF Core can then generate the database schema based on your model (Code-First approach) or scaffold a model from an existing database (Database-First approach).

Learn More

For more in-depth information, explore the following resources:

• EF Core Documentation Home
• Getting Started with EF Core
• EF Core Providers
• EF Core Migrations