Entity Framework 6

This section delves into Entity Framework 6 (EF6), the latest major version of Entity Framework within the broader ADO.NET data access technologies for the .NET Framework.

What is Entity Framework 6?

Entity Framework 6 is an object-relational mapper (ORM) that enables developers to work with relational data as if they were dealing with regular .NET objects. It abstracts away the underlying database complexity, allowing developers to focus on business logic rather than writing repetitive data access code.

Key Features and Improvements in EF6

Code-First and Database-First Improvements: Enhanced experiences for both modeling your application starting from code and generating code from an existing database.
Improved Performance: Significant optimizations in query execution, connection management, and materialization of entities.
Dependency Injection: Built-in support for dependency injection, making it easier to manage DbContext lifetimes and inject dependencies in your application.
Pluggable Execution Strategy: Allows you to plug in custom logic for handling transient database exceptions, improving application resilience.
Connection Resiliency: Automatic retries for database operations that fail due to transient connectivity issues.
Asynchronous Operations: Native support for asynchronous query execution and saving changes, improving application responsiveness, especially in web scenarios.
Bulk Operations: Introduced capabilities for more efficient bulk insert, update, and delete operations.
Extensibility: Further extensibility points for customizing EF behavior, such as interceptors for logging or modifying commands.

Core Concepts in EF6

While the core concepts of Entity Framework remain consistent, EF6 refines and expands upon them:

DbContext: The primary class for interacting with the database. It represents a session with the database and is used to query and save data.
DbSet<TEntity>: Represents a collection of a given entity type in the context, providing methods to query and manipulate entities.
Entity: A regular .NET object that represents a row in a database table.
Migrations: A feature that allows you to evolve your database schema over time in sync with your code model.
LINQ to Entities: The primary mechanism for querying data using Language Integrated Query (LINQ).

Getting Started with EF6

To get started with EF6, you typically need to:

Install the EF6 NuGet package: Install-Package EntityFramework
Define your entity classes.
Define your DbContext class.
Configure your database connection.
Use the DbContext to query and save data.

Example: Basic DbContext and DbSet


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

                    public BlogContext() : base("name=MyConnectionString")
                    {
                    }
                }

                public class Blog
                {
                    public int BlogId { get; set; }
                    public string Name { 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; }
                }

EF6 vs. Entity Framework Core

It's important to note that while EF6 is still widely used, Microsoft has also developed Entity Framework Core (EF Core). EF Core is a modern, cross-platform, high-performance, and extensible version of Entity Framework. EF6 continues to be supported for the .NET Framework, while EF Core is the recommended choice for new .NET Core and .NET 5+ applications.

Note: For new development targeting modern .NET platforms (.NET Core, .NET 5+), consider using Entity Framework Core. EF6 is primarily for .NET Framework applications.

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