ef-code-first

问题 I'm new to the code first methodology. I'm getting this error: "The model backing the 'DataContext' context has changed since the database was created. Consider using Code First Migrations to update the database". I have a WPF app using EF6 & MVVM running against a local db (.mdf life). I created a new model, called langauges then I added a new DbSet< langauges > collection to my datacontext. When the code tries to instantiate the a datacontext object, I get the error above. What am I missing

问题 When using EF 4.1 Code First, is it possible to create User-Defined Data Types for your schema? 回答1: Simple answer is no. Longer answer: Current EF implementation leads to multiple issues when trying to use user defined types: The type must be defined prior to its usage in table's DDL definition. Because of that the type cannot be defined in Seed method of database initializer (as often used for other database constructs like triggers or indexes). To make this work you must create whole new

问题 I am using Visual Studio 2010, C# 4.0 and Entity Framework 5.0. I have been using database first development for many years but am trying to move to code first and am running into problems. Reading and searching does not seem to address the problems I have simplified my problem as follows - I have two classes - Assessors and Documents. public class Assessor { public int AssessorID { get; set; } public virtual List<Document> Documents { get; set; } } public class Document { public int

问题 I'm having trouble getting EF 4.1 working on my computer. It seems to be some problem with my database settings. I was trying out this simple walkthrough: http://blogs.msdn.com/b/adonet/archive/2011/03/15/ef-4-1-code-first-walkthrough.aspx But when it reaches db.Categories.Add(food); it just freeze. I have a normal SQL Server 2008 R2 installed, not SQL Express. There also seems to be some problems with creating .mdf files instead of a direct connection to the localhost SQL server. I've also

问题 I'm using Entity Framework Code-First and this is my DbContext . As you see there is nothing about DbSet<> properties and all of that will provide from my model classes which are providing by C# CodeDOM . I'm creating my Tables dynamically by using Code-First . public class MyDBContext : DbContext { public MyDBContext() : base("MyCon") { Database.SetInitializer<MyDBContext>(new CreateDatabaseIfNotExists<MyDBContext>()); } protected override void OnModelCreating(DbModelBuilder modelBuilder) {

问题 I am using code first migrations to create and update the database for my asp mvc site. I have a DbContext, which is in another project in the solution. public class EFDbContext : DbContext { public DbSet<Book> Books { get; set; } public DbSet<Author> Authors { get; set; } public DbSet<Publisher> Publishers { get; set; } } When i enable-migrations and add-migration [name] . It seems to create its own db called [foo-projectname].Domain.Concrete.EFDbContext Instead of the attaching to the

问题 Every time I try to debug anything in c# asp.net I get this error. Error = Unable to evaluate the expression. Operation not supported. Unknown error: 0x80070057. alongside something like this Local = Evaluation of method System.Data.Entity.DbSet`1[appname.DataLayer.Entities.GameResultEntity].get_Local() requires use of the static field System.Data.Entity.Infrastructure.DbContextInfo._currentInfo, which is not available in this context. In this case, all I'm doing is adding something to the

问题 I have a very simple unidirectional class mappings. public class MyDbContext : DbContext { public MyDbContext() : base("CodeFirstDatabase") { } public DbSet<Contact> Contacts { get; set; } public DbSet<PhoneNumber> Number { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Conventions.Remove<PluralizingTableNameConvention>(); modelBuilder.Conventions.Remove<IncludeMetadataConvention>(); modelBuilder.Entity<Contact>() .HasMany(c => c.Numbers)

问题 Code I have two very simple interfaces in my application Represents entities that are saved in the database public interface IEntity { int Id { get; set; } } Entities that have only the Nome field as required field to save the entity public interface IEntityName : IEntity { string Nome { get; set; } } And many classes implementing this interface public class Modalidade : IEntityName { public int Id { get; set; } public string Nome { get; set; } } public class Nacionalidade : IEntityName {

问题 Have started to use Entity Code First with Azure Mobile Services and have met some issue: For using TableController with Entity objects I need to derive each of them from EntityData class, that provide string Id field! I used to use int, long and even guid instead string for id, so... What is benefits of this? What about insert operation and what is the best practice for this? What about performance for string id? 回答1: @carlosfigueira has a good writeup about the change to using string id