实体框架代码的前1对1..0关系

Question

I seem to have a unique problem with Entity Framework achieving 1 to 0..1 relationship; I have two entities.

1. FamilyMember
2. ImageStore

FamilyMember stores the person's details and I have ImageStore where profile picture is being stored but it is not required. So FamilyMember may or may not have a profile picture. The problem I have is: When I have a profile picture stored in ImageStore, it retrieves the FamilyMember object with ImageStore data but when I don't have profile picture in ImageStore, whole FamilyMember object comes out to be null instead of only ImageStore object in FamilyMember being null. I struggled on this issue for a day before returning for a help.

I am using Sqlite with Entity Framework 6.0

Let me start with two models:

FamilyMember

public class FamilyMember : PropertyChangedNotification
    {
        [Key]
        public long FamilyMemberId { get; set; }
        [ForeignKey("ImageStore")]
        public int? ProfilePictureId { get; set; }       
        public ImageStore ImageStore { get; set; }
    }

ImageStore

public class ImageStore : PropertyChangedNotification
    {
        [Key]
        public int ImageStoreId { get; set; }
        [Required]
        public string ImageFile { get; set; }
        [Required]
        public Byte[] ImageBlob { get; set; }
        public string FileName { get; set; }
        [Required]
        public int FileSize { get; set; }        
    }

Here is my DataContext

public class ADataContext : DbContext
    {
        public ADataContext()
            : base("name=ADataContext")
        {

        }

        public ADataContext(string filename, string password)
            : base(new SQLiteConnection()
            {
                ConnectionString =
                    new SQLiteConnectionStringBuilder()
                    {DataSource = filename, ForeignKeys = true, Password = password }
                        .ConnectionString
            }, true)
        {
        }

        public ADataContext(string filename)
            : base(new SQLiteConnection()
            {
                ConnectionString =
                    new SQLiteConnectionStringBuilder() { DataSource = filename, ForeignKeys = true }
                        .ConnectionString
            }, true)
        {
            Database.SetInitializer<ADataContext>(null);
        }

        public DbSet<FamilyMember> FamilyMembers { get; set; }        
        public DbSet<ImageStore> ImageStore { get; set; }        

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {                
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();    
            modelBuilder.Entity<FamilyMember>().HasOptional(s => s.ImageStore);                
        }
    }

And here is the LINQ statement where I am getting the FamilyMember Data using eager loading

familyMember =  _dbContext.FamilyMembers.Include("ImageStore").FirstOrDefault(x => x.FamilyMemberId == memberId);

Answer 1

I think, I finally found a solution to a problem. Database table and model was not matching. There was one required field in model which was not created with NOT NULL constraint. When I created a row in database, that field was null and when entity framework was getting that row, it was silently dropping it instead of complaining about it. Finally fixed the problem by bringing the database in sync with the model.