entity-framework-4.1

I have a table with 9 columns in database and I want to be able to load only some fields of it if I need. How can I do this with Entity Framework 4 please? e.g. My table has these fields: ID, FirstName, LastName, FotherName, BirthDate, Mobile, Email and I want to be able to fetch just these columns: ID, FirstName, LastName My project is an ASP.NET MVC 3 application, with SQLServer 2008 Express and EF 4.1 . Assume you have a table with this model: public class User{ public int ID {get; set;} public string NickName {get; set;} public string FirstName {get; set;} public string LastName {get; set;

We can stop creation of proxy in the context constructor by using this.Configuration.ProxyCreationEnabled = false; What are the advantages and disadvantages of creating proxies in EF 4.1 ? Proxies are necessary for two features: Lazy loading - navigation properties are loaded once accessed first time Dynamic change tracking - if you modify any property in the entity the context is notified about this change and set the state of the entity. If dynamic change tracking is not used, context must use snapshot change tracking which means discovery all changes before saving takes place = exploring

I've build a little WPF demo app which uses EF Code-First to save its data in a SQL CE 4.0 DB. It works fine unless I remove a property from a model object. For example, if I remove "HosteBy" from this class..... public class Dinner { public int DinnerID { get; set; } public string Title { get; set; } public DateTime EventDate { get; set; } public string Address { get; set; } public string HostedBy { get; set; } public virtual ICollection<RSVP> RSVPs { get; set; } } ...it throws this exception: The model backing the 'NerdDinners' context has changed since the database was created. Either

It seems that most of the focus with MVC3 and EF4.1 is around "code first" - I can't seem to find any examples or tutorials that meet the following criteria: uses an existing SQLServer database has separate projects for web & data access (we will have multiple web apps sharing the same data access classes) recommendations for validation Does such an example or tutorial exist? Are there any documented "best practices" for how to accomplish this, or rationale for NOT having a solution structured this way? Ladislav Mrnka It is quite common scenario and it depends if you want to use EDMX file for

I am running into an interesting performance issue with Entity Framework. I am using Code First. Here is the structure of my entities: A Book can have many Reviews. A Review is associated with a single Book. A Review can have one or many Comments. A Comment is associated with one Review. public class Book { public int BookId { get; set; } // ... public ICollection<Review> Reviews { get; set; } } public class Review { public int ReviewId { get; set; } public int BookId { get; set; } public Book Book { get; set; } public ICollection<Comment> Comments { get; set; } } public class Comment { public

I have a database called ApplicationName_Development running on SQL Server 2008 R2 Developer edition on my development box. I added .NET membership tables to the database with no problem. When I tried to get Code First working I received the following error message: The server encountered an error processing the request. The exception message is "Model compatibility cannot be checked because the database does not contain model metadata. Ensure that IncludeMetadataConvention has been added to the DbModelBuilder conventions. After some googling, I discovered that I had to delete the database and

I have two entities referenced one to many. When entity framework created the table it creates two foreign keys, one for the key I have specified with the fluent interface and the other for the ICollection. How do I get rid of the duplicate foreign key? public class Person { public long RecordId { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public string Email { get; set; } public string Username { get; set; } public long DepartmentId { get; set; } public virtual Department Department { get; set; } } public class Department { public long RecordId {