code-first

问题 Hello I'm trying to create some seeds for my project, but I'm having trouble seeding the Many-To-Many relationship data to the db. My database looks like this: in TeacherSkills , Teacher_ID and Skill_ID are foreign keys for their tables ofcourse. My seeder looks like this protected override void Seed(Ability_Examen_ASP.Models.AbilityDbContext context) { if (!context.Skills.Any()) { context.Skills.Add(new Models.Skill { SkillName = "PHP" }); context.Skills.Add(new Models.Skill { SkillName =

问题 I have a class that inherits a base class to which another class has relationships. Example: Base class: Animal Subclass 1: Dog Subclass 2: Cat Related one-to-many table: Vaccinations A dog can have multiple vaccinations. This is implemented as a List<Vaccination>. A cat can have multiple vaccinations. A vaccination record can only have one animal associated with it. A vaccination doesn't know if it's associated with a dog or a cat. (Dogs and cats use non-colliding GUIDs.) There is no Animal

问题 I have a class that inherits a base class to which another class has relationships. Example: Base class: Animal Subclass 1: Dog Subclass 2: Cat Related one-to-many table: Vaccinations A dog can have multiple vaccinations. This is implemented as a List<Vaccination>. A cat can have multiple vaccinations. A vaccination record can only have one animal associated with it. A vaccination doesn't know if it's associated with a dog or a cat. (Dogs and cats use non-colliding GUIDs.) There is no Animal

问题 I'm having trouble creating my database with EF code-first. I have an entity Player and an entity friedship. Each friendship references two players. One of the players is the sender, the other one is the receiver of the friendship. This are my entities: Player.cs public class Player { public int PlayerId { get; set; } [Required] public string Name { get; set; } [Required] public string Email { get; set; } [InverseProperty("Receiver")] public virtual List<Friendship> FriendshipsIncoming { get;

问题 I'm using EF5 Code First in MVC4. There are tables where fields have decimal datatypes. I just wanted to update the precision of decimal originally from (18,2) to (18,4) . Please help. To achieve the goal I just modified the OnModelCreating something like this: protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<DealerLevelDiscount>().Property(d =>d.Discount ).HasPrecision(18, 4); modelBuilder.Entity<DealerTransaction>().Property(d => d.ProductDiscount)

问题 I have these tables: Category CategoryId CategoryTitle ... ICollection<Article> Articles Each category can have several articles: Article ArticleId ArticleTitle NumberOfComment NumberOfView ... ICollection<ArticleReview> Reviews And each article has several reviews by some user: ArticleReview ArticleReviewId ReviewPoint ArticleId ReviewerId i am trying to export excel report using EPPlus package Here is my ExcelExport class : public class excelExport { public string ArticleTitle { get; set; }

问题 I just started to make my first project with Codefirst-Approach with C#, Linq and MSSQLSERVER and run into an problem when trying to insert a new DB-entry that contains an reference to an already existing element from another table. InnerException {"Violation of PRIMARY KEY constraint 'PK_dbo.Manufacturers'. Cannot insert duplicate key in object 'dbo.Manufacturers'. The duplicate key value is (1d262e43-b9b6-4752-9c79-95d955d460ab).\r\nThe statement has been terminated."} System.Exception

问题 I created an Microsoft unity project (my first using Dependency Injection) with my home controller working fine as expected having registered my messaging Class as follows private static IUnityContainer BuildUnityContainer() { var container = new UnityContainer(); container.RegisterType<IMessageService, MessageService>(new HierarchicalLifetimeManager()); RegisterTypes(container); return container; } The challenge is I intend making this project a parent to several modules that will be plugins

问题 I've got a class User which has an attribute Name that must be unique. So far I've investigated 3 ways of checking this: Annotations [StringLength(100)] [Index(IsUnique = true)] public string Name { get; set; } Problem is, by trying to insert a user with a repeated name it throws this ex: as you can see, I would have to navigate into the inner exceptions (which I don´t know if it is possible, but I assume it is) and the last inner exception´s message is not user friendly at all. Fluent Api

问题 I've got a class User which has an attribute Name that must be unique. So far I've investigated 3 ways of checking this: Annotations [StringLength(100)] [Index(IsUnique = true)] public string Name { get; set; } Problem is, by trying to insert a user with a repeated name it throws this ex: as you can see, I would have to navigate into the inner exceptions (which I don´t know if it is possible, but I assume it is) and the last inner exception´s message is not user friendly at all. Fluent Api