Question

I’m working with WebMatrix and EntityFramework.

In my database I have a user table, in our business logic a user can create or update the content of another table, so my user class in my model is like this:

[Table("Users")]
public class User
{
    [Key]
    public int UserId { get; set; }

    [MaxLength(50), MinLength(5), Required]
    public string UserName { get; set; }

    [MaxLength(16), MinLength(8), Required]
    public string Password { get; set; }

    [MaxLength(50), Required]
    public string Name{ get; set; }

    [MaxLength(50), Required]
    public string LasName1{ get; set; }

    [MaxLength(50), Required]
    public string LasName2{ get; set; }

    public string token { get; set; }

    public DateTime CreatedDateTime { get; set; }

    public DateTime UpdatedDateTime { get; set; }

    [InverseProperty("CreatedBy")]
    public virtual ICollection<Device> CreatedDevices {get; set;}

    [InverseProperty("UpdatedBy")]
    public virtual ICollection<Device> UpdatedDevices {get; set;}

    [InverseProperty("CreatedBy")]
    public virtual ICollection<Cluster> CreatedClusters {get; set;}

    [InverseProperty("UpdatedBy")]
    public virtual ICollection<Cluster> UpdatedClusters {get; set;}

    [InverseProperty("CreatedBy")]
    public virtual ICollection<Region> CreatedRegions {get; set;}

    [InverseProperty("UpdatedBy")]
    public virtual ICollection<Region> UpdatedRegions {get; set;}
}

For exampl,e my Region class looks like this:

[Table("Regions")]
public class Region
{
    [Key]
    public int RegionId { get; set; }

    [MaxLength(50), MinLength(5), Required]
    public string Name{ get; set; }

    public virtual ICollection<Cluster> Clusters { get; set; }

    public DateTime CreatedDateTime { get; set; }

    public DateTime UpdatedDateTime { get; set; }

    public Usuario CreatedBy { get; set; } 

    public Usuario UpdatedBy { get; set; }
}

This creates the necessary relationships between the entities in the database. Now comes my main doubt, in my Cluster table there’s a CreatedBy_UserId, so when I’m doing the insert or update of an entry in the table, do I have to pass a User object? I’m saying something like this

Cluster cluster = new Cluster()
{
   RegionId = regionId,
   CreatedDateTime = createdDateTime,
   UpdatedDateTime = updatedDateTime,
   CreatedBy = currentUser,
   UpdatedBy = currentUser
};

Or how do I pass an int representing the foreign key to the table?

Answer 1

If you don’t have a foreign key property in your model, then yes, you need to set the navigation properties to establish a relationship. You only must make sure that currentUser is attached to the context – by loading it from the DB or attaching manually. Otherwise EF would also create new users. An example is this:

using (var context = new MyContext())
{
    context.Users.Attach(currentUser);
    Cluster cluster = new Cluster()
    {
        RegionId = regionId,
        CreatedDateTime = createdDateTime,
        UpdatedDateTime = updatedDateTime,
        CreatedBy = currentUser,
        UpdatedBy = currentUser
    };
    context.Clusters.Add(cluster);
    context.SaveChanges();
}

SaveChanges will create an INSERT statement with the correct foreign key values (equal to currentUser.UserId) set.