why we need Entity Framework Core (EF Core)

Entity Framework Core (EF Core) is an open-source object-relational mapping (ORM) framework for .NET applications. It enables developers to work with relational databases using .NET objects, eliminating the need for much of the tedious data access code that would typically be written. Here’s an overview of Entity Framework Core and its key features:

Purpose

• Object-Relational Mapping (ORM): EF Core allows developers to interact with relational databases using strongly-typed .NET objects (entities) rather than directly writing SQL queries.

• Database Abstraction: It provides a level of abstraction over the underlying database schema, allowing developers to focus more on application logic rather than database-specific details.

• Cross-Platform: EF Core is cross-platform and can be used with .NET Core as well as the full .NET Framework, making it versatile for developing applications on various platforms.

Key Features

1. Code-First Approach:

   • Developers define the entity classes and their relationships in code. EF Core then generates the corresponding database schema based on these definitions.

2. Automatic CRUD Operations:

   • EF Core handles the creation, retrieval, updating, and deletion (CRUD) operations of entities in the database, reducing the amount of boilerplate code developers need to write.

3. LINQ Support:

   • It supports Language-Integrated Query (LINQ), allowing developers to write queries using C# or VB.NET syntax directly against the entity classes.

4. Migrations:

   • EF Core includes a migration system that automates the process of updating the database schema to match changes in the entity classes.

5. Provider Model:

   • EF Core supports multiple database providers (SQL Server, PostgreSQL, SQLite, MySQL, etc.) through a provider model, enabling developers to switch databases without changing much of the application code.

6. Performance Optimization:

   • It includes features like batching of SQL statements, query caching, and lazy loading to optimize performance and reduce database round-trips.

Usage

• Integration: EF Core is integrated with ASP.NET Core for data access in web applications, but it can also be used in any .NET application, including console applications, Windows services, and more.

• Flexibility: Developers have the flexibility to choose between database-first, model-first, or code-first approaches based on project requirements and preferences.

Example Code (Code-First Approach)

// Example entity class
public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
}

// DbContext class
public class AppDbContext : DbContext
{
    public DbSet<Product> Products { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("your_connection_string_here");
    }
}

In this example, Product is an entity class, and AppDbContext is a subclass of DbContext that represents the database context. DbSet<Product> in AppDbContext represents a collection of Product entities that can be queried and manipulated.