What is EF Core (Entity Framework Core)?

Definition: EF Core (Entity Framework Core)

EF Core (Entity Framework Core) is a modern, open-source, and cross-platform version of the popular Entity Framework data access technology. It is a lightweight, extensible, and high-performance Object-Relational Mapper (ORM) for .NET applications, allowing developers to work with databases using .NET objects.

Overview of EF Core (Entity Framework Core)

Entity Framework Core, commonly known as EF Core, is an advanced ORM developed by Microsoft. It serves as a bridge between your .NET applications and various types of databases, including relational and NoSQL databases. EF Core simplifies the data access layer by providing a rich set of features that facilitate CRUD (Create, Read, Update, Delete) operations without the need for extensive SQL code.

Benefits of EF Core

1. Cross-Platform Support

EF Core is designed to work on multiple platforms including Windows, Linux, and macOS. This makes it a versatile choice for developers building applications intended to run on different operating systems.

2. High Performance

EF Core has been optimized for performance, ensuring that applications can handle large volumes of data with minimal latency. It includes features like batching of database commands and compiled queries to boost performance.

3. Extensibility

The architecture of EF Core is highly extensible, allowing developers to customize and extend its functionality. This flexibility makes it suitable for a wide range of applications, from simple CRUD operations to complex database interactions.

4. Migration Support

EF Core provides a robust migration framework that helps manage database schema changes over time. Developers can use migrations to evolve the database schema without losing data, making it easier to maintain and update applications.

5. Modeling

EF Core allows for rich data modeling using .NET classes. Developers can define relationships, constraints, and data annotations within their model classes, which EF Core then translates into database schema and operations.

6. Support for Various Databases

EF Core supports a variety of databases out-of-the-box, including SQL Server, SQLite, PostgreSQL, MySQL, and even Azure Cosmos DB. This extensive database support makes it a versatile tool for different project needs.

Key Features of EF Core

1. Change Tracking

EF Core automatically tracks changes to objects retrieved from the database, which helps in efficient updates by only sending modified data back to the database.

2. LINQ Queries

Developers can write complex queries using LINQ (Language Integrated Query), which are then translated into SQL queries by EF Core. This allows for writing more readable and maintainable code.

3. Lazy Loading

EF Core supports lazy loading, which means that related data is only loaded when it is explicitly accessed. This can improve performance by reducing the amount of data retrieved from the database.

4. Concurrency Handling

EF Core provides mechanisms to handle concurrency conflicts, ensuring that changes made by different users do not overwrite each other accidentally.

5. Database Seeding

Developers can use database seeding to populate a database with initial data, which is especially useful for setting up development and testing environments.

6. Raw SQL Queries

While EF Core abstracts most SQL operations, it also allows developers to execute raw SQL queries when necessary. This provides flexibility for complex scenarios that might not be easily handled by LINQ.

How to Use EF Core

1. Installation

To get started with EF Core, you need to install the appropriate NuGet package. For example, to use EF Core with SQL Server, you would install Microsoft.EntityFrameworkCore.SqlServer.

shellCopy codedotnet add package Microsoft.EntityFrameworkCore.SqlServer

2. Creating a Model

Define your data model using .NET classes. Each class represents a table in the database, and each property represents a column.

public class Blog<br>{<br>    public int BlogId { get; set; }<br>    public string Url { get; set; }<br>    public List<Post> Posts { get; set; }<br>}<br><br>public class Post<br>{<br>    public int PostId { get; set; }<br>    public string Title { get; set; }<br>    public string Content { get; set; }<br>    public int BlogId { get; set; }<br>    public Blog Blog { get; set; }<br>}<br>

3. DbContext Configuration

Create a DbContext class that manages the entity objects during runtime. It includes the DbSet<T> properties for each entity in the model.

public class BloggingContext : DbContext<br>{<br>    public DbSet<Blog> Blogs { get; set; }<br>    public DbSet<Post> Posts { get; set; }<br><br>    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)<br>    {<br>        optionsBuilder.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=Blogging;Trusted_Connection=True;");<br>    }<br>}<br>

4. Database Migrations

Use EF Core’s migration tools to create and apply migrations to keep the database schema in sync with your model.

dotnet ef migrations add InitialCreate<br>dotnet ef database update<br>

5. CRUD Operations

Perform CRUD operations using the DbContext. EF Core will translate these operations into SQL commands.

using (var context = new BloggingContext())<br>{<br>    // Create<br>    var blog = new Blog { Url = "http://sample.com" };<br>    context.Blogs.Add(blog);<br>    context.SaveChanges();<br><br>    // Read<br>    var blogs = context.Blogs.ToList();<br><br>    // Update<br>    blog.Url = "http://sample2.com";<br>    context.SaveChanges();<br><br>    // Delete<br>    context.Blogs.Remove(blog);<br>    context.SaveChanges();<br>}<br>

Advanced Topics in EF Core

1. Query Types

EF Core supports query types that allow you to run queries against data that isn’t mapped to an entity type. This is useful for scenarios like reporting where you need to run complex queries.

2. Global Query Filters

Global query filters allow you to define filters that are automatically applied to all queries involving a given entity type. This is useful for implementing soft deletes or multi-tenancy.

3. Value Conversions

EF Core allows you to define conversions for properties to control how values are read from and written to the database. This is useful for mapping complex types to database columns.

4. Owned Types

Owned types are a way to define types that are owned by another entity. This helps in modeling complex types that do not have their own table but are part of another table.

5. Interceptors

Interceptors allow you to intercept operations executed by EF Core. This can be useful for logging, caching, and other cross-cutting concerns.

Frequently Asked Questions Related to EF Core (Entity Framework Core)