Properties of type ObjectQuery<T>, like myContext.Product, always query the DB. That’s what they do. In EF 4.1 you can use DbSet<T>.Local to query memory. In EF < 4.1 you would use: ObjectContext.ObjectStateManager.GetObjectStateEntries(EntityState.Added).Select(o => o.Entity).OfType<Product>()
Find calls DetectChanges internally, SingleOrDefault (or generally any query) doesn’t. DetectChanges is an expensive operation, so that’s the reason why Find is slower (but it might become faster if the entity is already loaded into the context because Find would not run a query but just return the loaded entity). If you want to use … Read more
If you just need to run Seed() again, and nothing has changed that would cause a new migration to be added, just call Update-Database again with no flags and it will say ‘No pending migrations’, and run Seed() again for you. Seed() is called every time the DB is updated, regardless if there are new … Read more
If your view does not contain the primary key column,then it wont add to edmx file.
The “Update Model from Database” is hard/slow to use and is prone to errors. It generates other stuff that you probably don’t want/need. So manually adding the column that you need will work better. I suggest you do it outside the VS editor since depending on how many models/tables, it can be very slow opening … Read more
You need to delete the ItemTypeItem. It is not possible to just remove it from the Items list as it cannot exist by itself, because it has a non-nullable foreign key referencing ItemType (ItemTypeID). To delete the ItemTypeItem add context.Entry(itemTypeItem).State = EntityState.Deleted;
An imperfect solution is to just merge these interfaces you want to persist into base classes and break down the underlying objects with subclasses. EF does support this, and if you go with Table Per Hierarchy (the default), you can sort all of the underlying subclassed objects by a shared property using a regular LINQ … Read more
Based on a test I’ve just made both results are the same. using Table Level or QueryLevel AsNoTracking result in no entities being hold into tine ChangeTracker. But either way, entities from Table2 are never put inside of the ChangeTracker, as you can see in the WithtoutAsNoTracking test. Base on the assumption, that you are … Read more
That is because you didn’t pair your FK property with a navigation property. I expect the ParentID should point to parent OrganizationStructure and ChildrenItems should point to children OranizationStructures. If your model doesn’t contain Parent navigation property to parent OrganizationStructure you must use fluent-API to tell EF that ParentID is FK: modelBuilder.Entity<OrganizationStructure>() .HasMany(o => o.ChildrenItems) … Read more
but I get an ICollection in the last lambda displayed, so I obviously need the Select() No, you don’t. EF Core Include / ThenInclude totally replace the need of Select / SelectMany used in EF6. Both they have separate overloads for collection and reference type navigation properties. If you use the overload with collection, ThenInclude … Read more