how to setup code first entities

Question

I am struggling with the concept of code first entities, and data annotations.

I am trying to create a database which among others has a People table and an ensemble table which are linked by a one to many relationship as in each ensemble can have many people.

how exactly do I set up these classes to simulate a one to many relationship and more importantly how do I add data to each table.

I have tried the following:

//Ensemble entity class
public class Ensemble
{
    [Key]
    public int ensembleID { get; set; }
    public string ensembleName { get; set; }

    public virtual List<People> persons { get; set; }

    public Ensemble (int ensembleID, string ensembleName)
    {
        this.ensembleID = ensembleID;
        this.ensembleName = ensembleName;
    }
}

// people entity class
    public class People
{
    [Key]
    public int personID { get; set; }
    [Required]
    public string firstname { get; set; }
    [Required]
    public string surname { get; set; }
    [Required]
    public DateTime birthDate { get; set; }
    public string cellphone { get; set; }
    public string email { get; set; }
    public bool inSchool { get; set; }  //  Are they currently in a primary or secondary school

    public int ensembleID { get; set; }
    //[ForeignKey("ensembleID")]
    public Ensemble Ensemble { get; set; }


    public People(int personID, string firstname, string surname, DateTime birthDate, string cellphone, string email, bool inSchool, int ensembleID)
    {
        this.personID = personID;
        this.firstname = firstname;
        this.surname = surname;
        this.birthDate = birthDate;
        this.cellphone = cellphone;
        this.email = email;
        this.inSchool = inSchool;
        this.ensembleID = ensembleID;
    }


    // Adding data
    context.People.Add(new People(1, "Adam", "Herd", new DateTime(1992, 3, 12), "0274578956", "adamherd1@live.com", true));
    context.Ensemble.Add(new Ensemble(1, "Little River Band"));

However this returns an error. 'The INSERT statement conflicted with the FOREIGN KEY constraint \\"FK_dbo.People_dbo.Ensembles_ensembleID\\". The conflict occurred in database \\"SMMC_adam_stacy.Context\\", table \\"dbo.Ensembles\\", column 'ensembleID'.\\r\\nThe statement has been terminated."}'

Code snippets of how to do this correctly would be obliged as would furthur explanation of how navigation properites work eg public Virtual Ensemble Ensemble { get; set; }

Answer 1

context.Ensemble.Add(new Ensemble(1, "Little River Band"));
context.People.Add(new People(1, "Adam", "Herd", new DateTime(1992, 3, 12), "0274578956", "adamherd1@live.com", true));

Answer 2

Add people to the collection in Ensemble :

var ens = new Ensemble(1, "Little River Band");
var person = new People(1, "Adam", "Herd", new DateTime(1992, 3, 12),
                        "0274578956", "adamherd1@live.com", true)); 
                        // BTW: the constructor does not match the call
ens.persons.Add(person);
context.Ensemble.Add(ens);