entity-framework

问题 I seem to understand the reason behind taking help of MetadataTypeAttribute to Add Validation to the Model in case of Database First as we want to avoid the changes being overwritten when the model is generated from the database next time. I've noticed few people defining validation using MetadataType even when they're using Code First approach and there is no chance of their Entity Classes being overwritten by some kind of auto-generation of code. Does it make any sense to not apply these

问题 I am creating a greenfield application that uses EF Core which must talk to a legacy database. I want EF to ignore some of the columns in the database because they will eventually be deprecated and I don't want them in the new entity model. I can't remove them yet as the legacy system still relies on them. For an unwanted database column called DeprecatedFeature , I want to do something like: modelBuilder.Entity<MyEntity>(entity => { entity.HasKey(t => t.Id); entity.ToTable("MyEntity");

问题 Some RDBMSs (including SQL Server) support XML columns. I'd prefer not mapping such a column to the string data type. Does Entity Framework 6.1 support XML natively in any way? More specifically, can I map an xml column to one of the XML data types of .NET (such as XElement or XmlElement )? Does Entity Framework support XQuery that is integrated into normal LINQ queries and is translated to SQL queries? 回答1: No, only mapping it to string and then having to stream it back in to an XML document

问题 Let us suppose that we have one class which looks like the following: public class Entity { public IList<string> SomeListOfValues { get; set; } // Other code } Now, suppose we want to persist this using EF Core Code First and that we are using a RDMBS like SQL Server. One possible approach is obviously to create a wraper class Wraper which wraps the string: public class Wraper { public int Id { get; set; } public string Value { get; set; } } And to refactor the class so that it now depends on

问题 public class Station : IEntitie { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int Id { get; set; } public virtual ICollection<RegulatorySchedule> RegulatoryScheduleDispatchStations { get; set; } public virtual ICollection<RegulatorySchedule> RegulatoryScheduleDestinationStations { get; set; } } public class RegulatorySchedule : IEntitie { [Key] public int Id { get; set; } public virtual Station DispatchStation { get; set; } public virtual Station DestinationStation {

问题 public class Station : IEntitie { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int Id { get; set; } public virtual ICollection<RegulatorySchedule> RegulatoryScheduleDispatchStations { get; set; } public virtual ICollection<RegulatorySchedule> RegulatoryScheduleDestinationStations { get; set; } } public class RegulatorySchedule : IEntitie { [Key] public int Id { get; set; } public virtual Station DispatchStation { get; set; } public virtual Station DestinationStation {

问题 Our company is currently using Entity Framework Net Core 2.2 with Sql Server Trying to find all Distinct customers who purchased a certain Product Input Parameter . The following EF Linq query was written to get the distinct Customers. Later another question came up, how do we get more (navigation) properties of customer? Should Include be placed Before the Where or After the Where? Does it matter? When running the SQL Profiler, it noted no difference in the queries. I just wanted to be sure

问题 How would i go about adding the [AllowHtml] attribute to an entity framework generated class without the attribute being overwritten the next time the code is generated? I am looking to simply allow CKEditor to post information back to my MVC4 application using Razor without having to use [ValidateReuqest(false)] on my Content entity class. 回答1: You can use the [MetadataType] attribute to add metadata/attributes to your classes permanently without having to edit the original classes. For the

问题 I'm testing an endpoint under load. For 1 request per second, the average response time is around 200ms. The endpoint does a few DB lookups (all read) that are pretty fast and it's async throughout. However when doing a few hundred requests per second (req/sec), the average response time goes up to over a second. I've had a look at the best practices guide at: https://docs.microsoft.com/en-us/aspnet/core/performance/performance-best-practices?view=aspnetcore-2.2 Some suggestions like " Avoid

问题 Through looking at the posts here, I've seen two different ways of creating ASP.NET Identity roles through Entity Framework seeding. One way uses RoleManager and the other uses RoleStore . I was wondering if there is a difference between the two. As using the latter will avoid one less initialization string[] roles = { "Admin", "Moderator", "User" }; // Create Role through RoleManager var roleStore = new RoleStore<IdentityRole>(context); var manager = new RoleManager<IdentityRole>(roleStore);