Let’s assume that you have a collection of the properties to be excluded: var excluded = new[] { “property1”, “property2” }; With EF5 on .NET 4.5 you can do this: var entry = context.Entry(obj); entry.State = EntityState.Modified; foreach (var name in excluded) { entry.Property(name).IsModified = false; } This uses a new feature of EF5 on … Read more
This is too long question. You should break your problem into multiple separate questions next time. Code-first x Model-first x Database-first You are a database guy so the best approach for you is an incremental database-first approach where you define the stuff in DB (or VS Database tools) and update your model from the database. … Read more
It may occur because: DbContext configured with an incorrect connection string The entity specified is actually not mapped in configuration
For EF 5 use DbContext‘s ChangeTracker: public bool HasUnsavedChanges() { return this.ChangeTracker.Entries().Any(e => e.State == EntityState.Added || e.State == EntityState.Modified || e.State == EntityState.Deleted); } For EF 6 use the ChangeTracker.HasChanges() method which will also detect changes in many to many relationships: public bool HasUnsavedChanges() { return this.ChangeTracker.HasChanges(); }
With Entity Framework Core (tested with Version 2.1) you can get the current context using // DbSet<MyModel> myDbSet var context = myDbSet.GetService<ICurrentDbContext>().Context; How to get a DbContext from a DbSet in EntityFramework Core 2.0
You create custom initializer, which inherits from DropCreateDatabaseIfModelChanges or DropCreateDatabaseAlways interface. Like: public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<-YourDbContext-> And then you overwrite Seed method like: protected override void Seed(YourDbContext context) Whole example might look like: public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<EntitiesContext> { protected override void Seed(EntitiesContext context) { List<Role> roles = new List<Role> { new Role {Id=1, … Read more
Putting required on the Product table Category relationship field solves this public class Product { public int Id { get; set; } public string Name { get; set; } [Required] //<======= Forces Cascade delete public Category Category { get; set; } }
I think the problem is that as far as the context is concerned, you haven’t actually changed anything. You can use the lazy loading approach previously suggested by using virtual, but since you haven’t requested that the Employee be loaded yet, it’s still null. You could try this: var forceLoad = project.Employee; project.Employee = null; … Read more
The EDMX file is an XML file that is a combination of 3 different parts that make up the whole thing. If you right-click on your EDMX file and choose “Open with… XML Editor” you’ll see the 3 different sections: <edmx:ConceptualModels> <edmx:StorageModels> <edmx:Mappings> These sections can be edited manually, at your own risk! 🙂 That … Read more
The only way to get a collection of parents with a filtered children collection in a single database roundtrip is using a projection. It is not possible to use eager loading (Include) because it doesn’t support filtering, Include always loads the whole collection. The explicite loading way shown by @Daz requires one roundtrip per parent … Read more