MSDN Documentation

Introduction to Entity Framework

Entity Framework (EF) is a popular Object-Relational Mapper (ORM) for the .NET platform. It enables developers to work with relational data using domain-specific objects instead of requiring them to pass through most of the data, such as that stored in relational databases, without their being translated into an object-oriented program. When developers use an ORM like EF, they can interact with their data using familiar C# or Visual Basic constructs, such as classes, properties, and methods, and the framework handles the translation to and from the database.

What is Entity Framework?

Entity Framework provides a layer of abstraction over ADO.NET, simplifying data access operations. It allows you to define your database schema using C# or VB.NET classes (Code-First), map existing database schemas to your classes (Database-First), or generate code from an existing database model (Model-First).

Key Benefits

• Productivity: Reduces boilerplate data access code, allowing developers to focus on business logic.
• Maintainability: Simplifies code by using objects and LINQ for queries.
• Database Independence: Can work with various database providers (SQL Server, PostgreSQL, MySQL, SQLite, etc.) with minimal code changes.
• Type Safety: Queries are strongly typed, catching errors at compile time rather than runtime.

Core Components

Entity Framework's core functionality revolves around a few key concepts:

• DbContext: Represents a session with the database and is the primary way to query and save data. It allows you to query entities and track changes.
• DbSet<TEntity>: Represents a collection of all entities in the context, or that can be queried from the database, of a given type. A DbSet<TEntity> is typically accessed from a DbContext instance.
• Entities: POCO (Plain Old CLR Object) classes that represent tables in your database.
• LINQ to Entities: Allows you to write queries against your entities using Language Integrated Query (LINQ), which are then translated into SQL by EF.

Scenarios

EF is suitable for a wide range of applications, from simple desktop applications to complex enterprise-level web services:

• Web applications (ASP.NET Core, ASP.NET MVC)
• Desktop applications (WPF, Windows Forms)
• Mobile applications (Xamarin)
• Services and APIs

Getting Started

To start using Entity Framework, you typically need to:

1. Install the necessary Entity Framework NuGet packages.
2. Define your entity classes.
3. Create a DbContext class.
4. Configure your database connection.
5. Use the DbContext to query and save data.

For a step-by-step guide, please refer to the Getting Started section.