ef-code-first

问题 In fluent API, we can specify an Index on a field: var indexAttr = new IndexAttribute("IX_EmployeeNumber") { IsClustered = true }; Property(c => c.EmployeeNumber) .HasColumnAnnotation("Index", new IndexAnnotation(indexAttr )) .HasMaxLength(8) .IsRequired(); After Add-Migration , we will get this CreateIndex statement: CreateIndex("dbo.Employees", "EmployeeNumber", clustered: true, name: "IX_EmployeeNumber"); After a Update-Database , we have a sql like this: CREATE CLUSTERED INDEX [IX

问题 Is it possible to have Code First data classes declared with internal access as shown: internal class Person { public int Id { get; set; } public string Name { get; set; } } I have a requirement that classes and its properties should not be visible outside of the assembly. 回答1: As long as your DbContext derived class that exposes your class to EF is in the same assembly, you should be able to. I don't happen to design my apps that way as I prefer more separation. But the context should be

问题 I've got a classic Parent-Child relation that I would like to CRUD by using asp:GridView controls. To CRUD the parent is easy, but the challenge is to nest a asp:GridView within a asp:GridView that is able to work on the child relation. To make the problem easier, I've constructed an example. Consider the following EF-code: public class Context : DbContext { public DbSet<Animal> Animals { get; set; } public DbSet<Tag> Tags { get; set; } } public class Animal { public int AnimalID { get; set;

问题 I have a question about how to configure the one to many relationship with a join table using Code First fluent API. I have a Company, Contact Object both share a common Address Object like below Class Address { public int AddressId ..... } Class Company { public int CompanyId ...... public virtual ICollection<Address> Address } Class Contact { public int ContactID ....... public virtual ICollection<Address> Address } My expected DB structure would be Company Table CompanyId PK NOT NULL .....

问题 Simple, but yet mysterious for me: Why do StringPropertyConfiguration (and all the other PropertyConfiguration) class(es) have 2 overloads for IsConcurrencyToken() ? The first: public StringPropertyConfiguration IsConcurrencyToken() Configures the property to be used as an optimistic concurrency token. And the second: public StringPropertyConfiguration IsConcurrencyToken(bool?) Configures whether or not the property is to be used as an optimistic concurrency token. Why would you use one over

问题 I am trying to return as JSON the fully deep object (with all of the foreign key relationships filled in) but I am getting nulls for all the referenced objects. Here is the call to get the object: public ActionResult GetAll() { return Json(ppEFContext.Orders, JsonRequestBehavior.AllowGet); } And here is the Order object itself: public class Order { public int Id { get; set; } public Patient Patient { get; set; } public CertificationPeriod CertificationPeriod { get; set; } public Agency Agency

问题 I have a question about One-To-Many relationship between two tables when there is the link (join) table between. Example tables: ChildTable: ID int NOT NULL PK Relation int NOT NULL ParentTable: ID int NOT NULL PK Name nvarchar(50) NOT NULL ParentChildren: ParentTable_ID int NOT NULL PFK ChildTable_ID int NOT NULL PFK Entities: public class ChildTable { public ChildTable() { this.ParentTables = new List<ParentTable>(); } public int ID { get; set; } public int Relation { get; set; } public

问题 I have some urgent issue which I could not find answer for across the web. I am using CodeFirst EF 4.3.1 and I am getting an error: Violation of PRIMARY KEY constraint 'PK_T_CRProviders'. Cannot insert duplicate key in object 'dbo.T_CRProviders'. My code is: Models: public enum CRProviderEnums { PE_Abcd = 0, PE_Efgh } [Table("T_CRProviders")] public class CRProvider { [Key] [Required] public int Enum { get; set; } [Required] public string Name { get; set; } } [Table("T_CRSupportedResources")]

问题 The situation as follows: we have one big MVC project with database first approach on EF5.0: ObjectContext constructor: namespace xxx.Models { (...) public partial class xxxEntities : ObjectContext { #region Constructors /// <summary> /// (...) /// </summary> public xxxEntities() : base("name=xxxEntities", "xxxEntities") { this.ContextOptions.LazyLoadingEnabled = true; OnContextCreated(); } (...) connection string: <add name="xxxEntities" connectionString="metadata=res://*/Models.xxxModel

问题 I have an Entity Framework Model created using Entity Framework Code First that is using Table Per Hierarchy inheritance where the structure looks a little like this: public abstract class BaseState { public int Id { get; set; } public string StateName { get; set; } // etcetera } public class CreatedState : BaseState { public User Owner { get; set; } } public class UpdatedState : BaseState { public User Owner { get; set; } } Now what that creates is in my BaseStates table I have Owner_Id and