Fluent API - (EF Model Configuration and Annotations)

Fluent API is a powerful feature of Entity Framework (EF) that allows you to configure your model using a fluent, code-based syntax. In this tutorial, we'll look at how to use Fluent API to configure your model, and how it differs from using annotations.

Syntax

The syntax for using Fluent API in EF is as follows:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Entity>()
        .Property(e => e.Property)
        .HasMaxLength(50);
}

Example

Let's look at an example of using Fluent API to configure a model. Suppose we have the following entity class:

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

We can use Fluent API to configure this model as follows:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Product>()
        .HasKey(p => p.Id)
        .Property(p => p.Name)
        .HasMaxLength(100)
        .IsRequired()
        .IsUnicode(false)
        .HasColumnName("ProductName");
}

This code configures the Product entity to use Id as its primary key, sets the maximum length of Name to 100 characters, requires Name to be non-null, sets the Unicode flag to false, and renames the column to ProductName.

Explanation

Fluent API provides a code-based way to configure your model in EF. Using Fluent API allows you to configure your model in a more intuitive way than using annotations, and provides more flexibility in how you configure your model.

Use

Fluent API is useful when you want to create complex model configurations that can't be achieved using annotations alone. It also provides a more intuitive way to configure your model than using annotations.

Important Points

Here are some important points to keep in mind when using Fluent API in EF:

• Fluent API provides a code-based way to configure your model in EF.
• Fluent API is more flexible than using annotations, and allows you to create more complex model configurations.
• Fluent API provides a more intuitive way to configure your model than using annotations.

Summary

In this tutorial, we discussed Fluent API in EF, which provides a code-based way to configure your model. We covered syntax, example, explanation, use, and important points of Fluent API in EF. By using Fluent API, you can create more complex model configurations and provide a more intuitive way to configure your model in EF.