Question

This is my model class.

public class Lead
{
    private readonly ObservableCollection<String> m_tags = new ObservableCollection<string>();

    public int LeadId { get; set; }
    public string Title { get; set; }
    public ObservableCollection<String> Tags { get { return m_tags; } }

}

Does Entity Framework offer a way to represent this using either Model-First or Code-First?

EDIT: I’m looking for a way to do this without changing the public API of the model. The fact that there is some sort of Tags table shouldn’t be visible to the downstream developer.

Answer 1

Since your model has to be represented in a relational way, you can only use primitive types (that have an equivalent in a SQL DB) or other entities within a entity definition – that means the tags are represented by their own entity. In your case it would be something like this using Code first approach:

public class Lead
{
    public int LeadId { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Tag> Tags { get; set; }
}

public class Tag
{
    public int TagId { get; set; }
    public string Name { get; set; }
}

public class SomeContext : DbContext
{
    public DbSet<Lead> Leads { get; set; }
    public DbSet<Tag> Tags { get; set; }
}

This (by default) will be represented in the database as a table Leads, a table Tags, and a relationship table LeadTags that only contains {LeadId, TagId} pairs.