When we have a one-to-many relationship, we can say that a record in one table is related to multiple records in another table. 

An example of a one-to many relationship would be between a user and game sessions. Assuming that we have a User class and a GameSession class, the one-to-many relationship can be represented with the Fluent API as follows: 

protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>()
            .HasOne(u => u.GameSession)
            .WithMany(g => g.User)
            .HasForeignKey<GameSession>(u => u.UserForeignKey);
    }

The preceding code snippet still uses the .HasOne() property, but the difference is that it is chained to a .HasMany() property, making it a one-to many relationship.