使用Fluent API在实体框架中创建一对多关系

Question

I have the following POCO Classes:

public class Client
{
    public string ClientId { get; set; }
    public string CompanyId { get; set; }
    public string LastName { get; set; }
    public string FirstName { get; set; }

    [ForeignKey("AccountId")]
    public virtual ICollection<Note> Notes { get; set; } 
}

public class Note
{
    public decimal NoteId { get; set; } 
    public string AccountId { get; set; }
    public string NoteValue { get; set; }

    [ForeignKey("ClientId")]
    public virtual Client Client { get; set; }
}

and the following mapping classes:

    public ClientMap(string schema)
    {
        ToTable("CLIENTS", schema);

        // Primary Key
        HasKey(t => t.ClientId);

        // Properties
        Property(t => t.ClientId)
            .HasColumnName("CLIENT_ID")
            .IsRequired()
            .HasMaxLength(16);

        Property(t => t.CompanyId)
            .HasColumnName("COMPANY_ID")
            .IsRequired()
            .HasMaxLength(16);

        Property(t => t.LastName)
            .HasColumnName("LAST_NAME")
            .IsRequired()
            .HasMaxLength(50);

        Property(t => t.FirstName)
            .HasColumnName("FIRST_NAME")
            .IsRequired()
            .HasMaxLength(50);
    }

    public NoteMap(string schema)
    {
        ToTable("NOTES", schema);

        // Primary Key
        HasKey(t => t.NoteId);

        // Properties
        Property(t => t.NoteId)
            .HasColumnName("NOTE_ID")
            .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

        Property(t => t.AccountId)
            .HasColumnName("ACCOUNT_ID")
            .IsRequired()
            .HasMaxLength(16);

        Property(t => t.NoteValue)
            .HasColumnName("NOTE")
            .HasMaxLength(4000);
    }

In this model (Using Fluent API), there is a one to many relationship between clients and notes. ClientID is the PK in clients and NoteId is the PK in Notes. There are no foreign keys in the DB. ClientId maps to the AccountId in Notes.

I can not get this to work. When I run it, I can get most of the client data back, but when trying to navigate to a note, I get a Funcation Evaluation Timed out error when trying to look at Notes. I can not get the relationship between clients and notes to work. Where have I gone wrong? (I would like to do this using Fluent API)

Thanks

Answer 1

You are trying to create a typical one to many relationship. First, remove the data annotations that you are using in your model, you don't need them if you are going to use Fluent Api. Second, add the ClientId FK property in your Note entity

public class Note
{
    public decimal NoteId { get; set; } 
    public string AccountId { get; set; }
    public string NoteValue { get; set; }

    //FK property
    public int ClientId{get;set;}

    public virtual Client Client { get; set; }
}

Then, in the constructor of your NoteMap class, add this Fluent Api configuration:

 HasRequired(n=>n.Client).WithMany(c=>c.Notes).HasForeignKey(n=>n.ClientId);