ef-code-first

问题 I'm working on a project that at can end up with multiple UI versions / variants, but so far I've got two subprojects in my solution Web - containing Web interface with ASP.NET MVC. Service project is place where I have my database context and models defined. My Goal is to have minimum or possibly no references to EF specific code in my Web project. I want it to be independent so when I switch the dlls with service backend ( from let say SQL to XML or MySQL ) I shouldn't make multiple

问题 I am new to EF5 Code First and I'm tinkering with a proof-of-concept before embarking on a project at work. I have initially created a model that looked something like public class Person { public int Id { get; set; } public string FirstName { get; set;} public string Surname {get;set;} public string Location {get;set;} } And I added a few records using a little MVC application I stuck on the top. Now I want to change the Location column to an enum, something like: public class Person {

问题 I have the following code (Database is SQL Server Compact 4.0): Dim competitor=context.Competitors.Find(id) When I profile this the Find method takes 300+ms to retrieve the competitor from a table of just 60 records. When I change the code to: Dim competitor=context.Competitors.SingleOrDefault(function(c) c.ID=id) Then the competitor is found in just 3 ms. The Competitor class: Public Class Competitor Implements IEquatable(Of Competitor) Public Sub New() CompetitionSubscriptions = New List(Of

问题 I am having two object classes public class User { public Guid Id { get; set; } public string Name { get; set; } // Navigation public ICollection<Product> Products { get; set; } } public class Product { public Guid Id { get; set; } // Navigation public User User { get; set; } public Guid User_Id { get; set; } public string Name { get; set; } } When i load a user using dataContext, i get the list of Products being null (this is ok). If i add "virtual" keyword to Products list, public virtual

问题 I've followed MSDN on how to handle enumerations in Code First for EF6. It worked, as supposed to but the field in the created table that refers to the enumerator is a simple int . I'd prefer a second table to be produced, the values of which would follow the definition of the enumerator in C# code. So, instead of only getting a table corresponding to Department in the example on MSDN, I'd also like to see a second table populated by the items from Faculty . public enum Faculty { Eng, Math,

问题 I've followed MSDN on how to handle enumerations in Code First for EF6. It worked, as supposed to but the field in the created table that refers to the enumerator is a simple int . I'd prefer a second table to be produced, the values of which would follow the definition of the enumerator in C# code. So, instead of only getting a table corresponding to Department in the example on MSDN, I'd also like to see a second table populated by the items from Faculty . public enum Faculty { Eng, Math,

问题 I am currently working on a project using the latest version of Entity Framework and I have come across an issue which I can not seem to solve. When it comes to updating existing objects, I can fairly easily update the object properties ok, until it comes to a property which is a reference to another class. In the below example I have a class called Foo, which stores various properties, with 2 of these being instances of other classes public class Foo { public int Id {get; set;} public string

问题 I will like to know that is there a way to exclude some fields from the database? For eg: public class Employee { public int Id { get; set; } public string Name { get; set; } public string FatherName { get; set; } public bool IsMale { get; set; } public bool IsMarried { get; set; } public string AddressAs { get; set; } } How can I exclude the AddressAs field from the database? 回答1: In the current version the only way to exclude a property is to explicitly map all the other columns: builder

问题 I have two entities in my MVC application and I populated the database with Entity Framework 6 Code First approach. There are two city id in the Student entity; one of them for BirthCity, the other for WorkingCity. When I define the foreign keys as above an extra column is created named City_ID in the Student table after migration. Id there a mistake or how to define these FKs? Thanks in advance. Student: public class Student { public int ID { get; set; } public string Name { get; set; }

问题 I'm trying to set up a many to many relationship in EF code first but the default conventions is getting it wrong. The following classes describes the relationship: class Product { public int Id { get; set; } public string Name { get; set; } } class Account { public int Id { get; set; } public string Name { get; set; } public virtual ICollection<Product> Products { get; set; } } One Account can have many Products. However the EF conventions will create the DB tables as: Products Table -------