entity-relationship

I have two models: public class User { ..... public virtual UserProfile UserProfile { get; set;} } public class UserProfile { ..... public virtual User User { get; set;} } The User is the master table and the relation is one to one. One user has only one UserProfile. How can I define the relationship between User and UserProfile using EF CodeFirst Fluent API in such a way that when I delete one user from User table the user profile from Userprofile is also deleted? Use WillCascadeOnDelete modelBuilder.Entity<UserProfile>() .HasKey(c => c.Id) .HasRequired(c => c.User) .WithRequiredDependent(c =

I'm developing an Entity Framework Code First (v. 4.4.0.0) C# library with .Net Framework 4.0. I don't know how to set zero-to-one relationship. My model is the following: A Talk can be created by only one user ( StarterUserId ). A Talk can have only one recipient user ( RecepientUserId ) or only one group ( RecipientGroupId ). Note : That means that RecepientUserId is null if RecipientGroupId is not null; or RecepientUserId is not null if RecipientGroupId is null. A user can be a recipient of zero or n Talks , but a group can have zero or one Talk . This is Talk class: [DataContract] public

Somehow I can't figure out how to implement the following relations using Doctrine 2 syntax: I have Items and Shops. Each item has different price and different quantity at each shop. So, I have Items table, Shops table and ItemsAtShops table. How do I reflect the last one in Doctrine? I guess I need to create ItemsAtShops entity, relates ManyToOne -> Items and ManyToOne -> Shops, right? But in this case... how do I conveniently fetch a list of Items at the specific Shops with their prices and quantities at given Shops? So, that all these can be conveniently iterated? I need to render a page

I am trying out the objectify(version 2.2.3) embedded classes example (wiki) on google app engine. I am getting this error: java.lang.IllegalArgumentException: one: com.mypkg.LevelOne is not a supported property type. at com.google.appengine.api.datastore.DataTypeUtils.checkSupportedSingleValue(DataTypeUtils.java:184) The code I have is the same as the one in Wiki. The section in the controller: EntityWithEmbedded ent = new EntityWithEmbedded(); ent.one = new LevelOne(); ent.one.foo = "Foo Value"; ent.one.two = new LevelTwo(); ent.one.two.bar = "Bar Value"; The EntityWithEmbedded class: import

Assume i have two entities, User and Notification : public class User { [Key] public int UserId { get; set; } // other public properties // Navigation Properties public virtual ICollection<Notification> Notifications { get; set; } } public class Notification { [Key] public int NotificationId { get; set; } // other public properties // Navigation Properties public virtual ICollection<User> Users { get; set; } } I'm simply adding many-to-many Relationship like this: modelBuilder.Entity<User>() .HasMany(u => u.Notifications) .WithMany(t => t.Users) .Map(m => { m.ToTable("UserNotifications"); m