EF relationships

Many to many relationship

EF core doesn’t have a direct way to configure many to many.

We will create a new entity the Like and a User will have a one to many relationship using the “send like” property (Likees) and another using the “receive like property (Likers).

The Like entity

Create a new class Models/Like.cs

public class Like
    public int LikerId { get; set; }
    public User Liker { get; set; }
    public int LikeeId { get; set; }
    public User Likee { get; set; }

Add the new properties to the User

public ICollection<Like> Likers { get; set; }
public ICollection<Like> Likees { get; set; }

Add a new DbSet for the Like table to DatingContext and define the relationship in an override of OnModelCreating.

public DbSet<Like> Likes { get; set; }

Stop *dotnet run**

Add a new migration

dotnet ef migrations add AddedLikeEntity

Review the migration code. Note that ef created an index IX_Likes_LikeeId and not one for LikerId, that is because LikerId is the first part of the primary key so it is already indexed.

Apply the migration to the DB.

dotnet ef database update