Relationships: One-to-Many & Many-to-Many
Model and query one-to-many and many-to-many relationships with navigation properties and Fluent API.
Relationships in EF Core
EF Core models three types of relationships between entities: one-to-one, one-to-many, and many-to-many. Each is expressed with navigation properties and optionally configured with the Fluent API.
One-to-Many: Entity Setup
A Blog has many Posts. The dependent (Post) holds the foreign key. Navigation properties on both sides allow traversal in either direction.
public class Blog
{
public int Id { get; set; }
public string Name { get; set; } = "";
public ICollection<Post> Posts { get; set; } = new List<Post>();
}
public class Post
{
public int Id { get; set; }
public string Title { get; set; } = "";
public int BlogId { get; set; } // FK
public Blog Blog { get; set; } = null!; // nav property
}All lessons in this course
- DbContext & DbSet Basics
- Migrations & Schema Management
- CRUD Operations with EF Core
- Relationships: One-to-Many & Many-to-Many