You should have your entity create those lists in the constructor. EF doesn’t create dependent collections, and expects the entity to do so. So, your case, you would make your entity like this: class MyClass{ public List<OtherClass> _otherClasses {get;set;} public MyClass() { _otherClasses = new List<OtherClass>(); } }
The primary reason why I want to use this pattern is to avoid calling EF 4.1 specific data access operations from the domain. I’d rather call generic CRUD operations from a IRepository interface. This will make testing easier No it will not make your testing easier. You exposed IQueryable so your repository is not unit … Read more
Default length of string field in code first is 128. If you are using EF validation it will throw exception. You can extend the size by using: [StringLength(Int32.MaxValue)] public string Body { get; set; } This post became somehow popular so I’m adding second approach which also works: [MaxLength] public string Body { get; set; … Read more
If you are using SQL Server you must create custom database initializer and manually execute DBCC CHECKIDENT (‘TableName’, RESEED, NewSeedValue). For creating and using custom initializer with custom SQL commands check this answer.
You can ask mapping metadata to get names of key properties (there can be more then one): ObjectContext objectContext = ((IObjectContextAdapter)dbContext).ObjectContext; ObjectSet<YourEntity> set = objectContext.CreateObjectSet<YourEntity>(); IEnumerable<string> keyNames = set.EntitySet.ElementType .KeyMembers .Select(k => k.Name); Once you have key names you can use reflection to access their values. As you can see the approach reverts back to … Read more
If you don’t use lazy loading, you have the load the new Address explicitly (as you had to load it explicitly (with Include, for example), when you loaded the Person initially): context.Entry(myPerson).Reload(); // If the person refers to another Address in the DB // myPerson.Address will be null now if (myPerson.Address == null) context.Entry(myPerson).Reference(p => … Read more
You just need to set Configuration.ValidateOnSaveEnabled = false in your context class before calling SaveChanges(). context.Configuration.ValidateOnSaveEnabled = false; context.SaveChanges();
This is exception caused by SQL server when you have multiple paths of cascade deletes. If you delete your PaymentTerm it will trigger cascade delete on all three relations. This will blow up when creating either SalesOrder or Invoice. EF creates by default all one-to-many relations with ON DELETE CASCADE you can remap your specific … Read more
I add an example for the InversePropertyAttribute. It cannot only be used for relationships in self referencing entities (as in the example linked in Ladislav’s answer) but also in the “normal” case of relationships between different entities: public class Book { public int ID {get; set;} public string Title {get; set;} [InverseProperty(“Books”)] public Author Author … Read more
The problem is this one: MyEntity has an ID of 0 since it’s a new MyEntity. The Group is also new and contain a reference to MyEntity. So, MyEntity contains a list of Group which contain a reference back to MyEntity. The problem is that MyEntity.Group.MyEntity seems to be “new and not the same” as … Read more