Entity Framework: Introduction | MSDN Documentation

Introduction to Entity Framework

Entity Framework (EF) is a set of data access technologies for .NET Framework and .NET that enables developers to work with relational data as domain-specific objects. It eliminates the need for most of the data-access code that developers traditionally need to write. For example, with Entity Framework, developers can issue queries to SQL Server using LINQ, and then retrieve, insert, update, and delete data.

Note: Entity Framework is Microsoft's recommended Object-Relational Mapper (ORM) for .NET applications.

What is an Object-Relational Mapper (ORM)?

An Object-Relational Mapper (ORM) is a technique that bridges the gap between object-oriented programming languages and relational databases. It allows developers to interact with database tables and rows as if they were objects and their properties in the application code. This abstraction layer simplifies data manipulation and reduces the amount of boilerplate SQL code needed.

Key Features of Entity Framework

LINQ to Entities: Enables querying of data using Language Integrated Query (LINQ) syntax, which provides compile-time checking and IntelliSense support.
Model-First, Database-First, and Code-First: EF supports multiple development approaches for defining your data model.
Migrations: A powerful feature that allows you to evolve your database schema over time as your application's data model changes.
Change Tracking: EF automatically tracks changes made to entities, making it easy to update the database with those changes.
Relationship Mapping: Handles complex relationships between entities (one-to-one, one-to-many, many-to-many) seamlessly.

Why Use Entity Framework?

Entity Framework offers several advantages for .NET developers:

Increased Productivity: Significantly reduces the amount of repetitive data access code you need to write.
Improved Maintainability: Centralizes data access logic, making your codebase easier to understand and maintain.
Type Safety: LINQ to Entities provides compile-time checks for your queries, catching errors early in the development process.
Abstraction from Database: Allows you to focus on your business logic rather than the specifics of your database schema.
Cross-Database Support: While often used with SQL Server, EF can be configured to work with other relational databases.

Getting Started

To begin using Entity Framework, you typically need to:

Install the EF NuGet package: This is usually done via the NuGet Package Manager in Visual Studio.
Define your data model: Create classes that represent your database tables and their relationships.
Create a DbContext: This is your primary gateway to interacting with the database.
Perform data operations: Use LINQ to query, add, update, and delete data.

Tip: For new projects, consider using the Code-First approach to define your model directly in C# classes.

This section will guide you through the core concepts and features of Entity Framework, empowering you to build robust and efficient data-driven applications.