entity-framework-ctp5

问题 Given this code: public class Car { public virtual int CarId { get; set; } public virtual string TypeName { get; set; } public ConvertableNullable<double> Price { get; set; } } Where the ConvertableNullable is just a workaround to Nullable , but it doesn't inherit from it. Now, this my simple context, where i map, the car class to entity, and map every property of it public class MyDBContext : DbContext { public MyDBContext() : base( "data source=.;initial catalog=newDB1;integrated security

问题 Using Entity Framework 4 CTP5 Code First and this example Is it possible to access the discriminator value? I would like to use it in a projection like context.BillingDetails.Select(x => new { Number = x.Number, DiscrimitatorValue = /* how do I get the discriminator value? */ }); From this post I understand the discriminator cannot be mapped to a property but is there any other way of accessing it? 回答1: I may be late to the game on this one, but I just added a getter property to the base

问题 I am following this article on MSDN. I ported it to EF Code First. public interface IUnitOfWork { IRepository<Employee> Employees { get; } IRepository<TimeCard> TimeCards { get; } void Commit(); } public class HrContext : DbContext { public DbSet<Employee> Employees { get; set; } public DbSet<TimeCard> TimeCards { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Employee>() .HasMany(e => e.TimeCards) .WithOptional(tc => tc.Employee); } }

问题 I have the following scenario in my database. It is a record of Studies and those studies have other studies as prerequisites. In my DB design, it looks like this: And my code looks something like this: public class Study { public int ID { get; set; } public string Topic { get; set; } public byte TypeID { get; set; } public virtual StudyType Type { get; set; } public bool Deprecated { get; set; } public virtual ICollection<Study> Prerequisites { get; set; } } public class StudyType { public

问题 Attempting to cutover our EF4 solution to EF CTP5, and ran into a problem. Here's the relevant portion of the model: The pertinent relationship: - A single County has many Cities - A single City has a single State Now, i want to perform the following query: - Get all Counties in the system, and include all the Cities, and all the State's for those Cities. In EF4, i would do this: var query = ctx.Counties.Include("Cities.State"); In EF CTP5, we have a strongly typed Include, which takes an

问题 I'm using Entity Framework CTP5 and Code First. I need to change the Collation for a specific column in SQL Server. I believe the default collation is SQL_Latin1_General_CP1_CI_AS, but I need to change this one column colllation to SQL_Latin1_General_CP1_CS_AS (Case Sensitive). Is there a way to use ModelBuilder in Code First to change a specific column collation? BarDev 回答1: Model builder doesn't allow this but you can create custom database initializer and execute ALTER TABLE command. The

问题 I'm creating a POCO model to use with entity framework code first CTP5. I'm using the decoration to make a property map to a PK column. But how can I define a PK on more then one column, and specifically, how can I control order of the columns in the index? Is it a result of the order of properties in the class? Thanks! 回答1: You can specify the column order in the attributes, for instance: public class MyEntity { [Key, Column(Order=0)] public int MyFirstKeyProperty { get; set; } [Key, Column

问题 I'm using the mvc-mini-profiler in my project built with ASP.Net MVC 3 and Entity Framework code-first. Everything works great until I attempt to add database profiling by wrapping the connection in the ProfiledDbConnection as described in the documentation. Since I'm using a DbContext, the way I am attempting to provide the connection is through the constructor using a static factory method: public class MyDbContext : DbContext { public MyDbContext() : base(GetProfilerConnection(), true) { }

问题 I'm using the mvc-mini-profiler in my project built with ASP.Net MVC 3 and Entity Framework code-first. Everything works great until I attempt to add database profiling by wrapping the connection in the ProfiledDbConnection as described in the documentation. Since I'm using a DbContext, the way I am attempting to provide the connection is through the constructor using a static factory method: public class MyDbContext : DbContext { public MyDbContext() : base(GetProfilerConnection(), true) { }

问题 This blog post of the ADO.NET team shows in an example how to define Table-Per-Hierarchy Mapping in the Fluent API of Entity Framework Code-First. This is the (slightly simplified) example: public class Product { public int ProductId { get; set; } public string Name { get; set; } // more properties } public class DiscontinuedProduct : Product { public DateTime DiscontinuedDate { get; set; } } ... and the TPH mapping: modelBuilder.Entity<Product>() .Map<Product>(m => m.Requires("Type")