entity-framework

问题 I'm using ASP.Net Core 2.0 with Entity Framework and I am trying to return a model to a page that contains the Employment entity with it's collection of EmploymentDocument entities also included. For the latter I do not want to load the data (byte[]) column but I do want all the other columns, most importantly FileName. The linq query I have which loads everything including the data column is: var employment = await _context.Employment .Include(e => e.EmploymentDocuments) // will load all

问题 In EF Core 2.2 I had: var data = await _ArticleTranslationRepository.DbSet .Include(arttrans => arttrans.Article) .ThenInclude(art => art.Category) .Where(trans => trans.Article != null && trans.Article.Category != null && trans.Article.Category.Id == categoryId.Value) .GroupBy(trans => trans.ArticleId) .Select(g => new { ArticleId = g.Key, TransInPreferredLang = g.OrderByDescending(trans => trans.LanguageId == lang).ThenByDescending(trans => trans.LanguageId == defaultSiteLanguage).ThenBy

问题 In EF Core 2.2 I had: var data = await _ArticleTranslationRepository.DbSet .Include(arttrans => arttrans.Article) .ThenInclude(art => art.Category) .Where(trans => trans.Article != null && trans.Article.Category != null && trans.Article.Category.Id == categoryId.Value) .GroupBy(trans => trans.ArticleId) .Select(g => new { ArticleId = g.Key, TransInPreferredLang = g.OrderByDescending(trans => trans.LanguageId == lang).ThenByDescending(trans => trans.LanguageId == defaultSiteLanguage).ThenBy

问题 We have worked on a project for 1 month and there are 6 entities without any relationship with other entities. They are all simple entities. We have created 6 different classes for operations on each entity. SaveOrUpdateEntity() methods of classes are almost same as you think. It is something like that: public static ErrorType SaveOrUpdateEntity(Entity entity, int userID) { try { using (DataEntities ctx = new DataEntities()) { if (entity != null) { if (entity.entityID == 0) { entity

问题 I am getting the following error "The Entity Framework provider type 'MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity' registered in the application config file for the ADO.NET provider with invariant name 'MySql.Data.MySqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information." However I do have MySql.Data.dll and MySql

问题 I have the following child object that we use an expression to map our 'entity' to our 'domain' model. We use this when specifically calling our ChildRecordService method GetChild or GetChildren: public static Expression<Func<global::Database.Models.ChildRecord, ChildRecord>> MapChildRecordToCommon = entity => new ChildRecord { DateTime = entity.DateTime, Type = entity.Type, }; public static async Task<List<ChildRecord>> ToCommonListAsync(this IQueryable<global::Database.Models.ChildRecord>

问题 What is a correct way to select a property of optional navigation property entity framework? I am concerned that in case the navigation property will be null, then the error will be thrown when I try to access its (optional navigation property`s) property. Here is what I tried: return await this.relatedCasesRepository .GetAll() .AsNoTracking() .Where(rc => rc.FirstCaseId == caseId || rc.SecondCaseId == caseId) .Select(rc => new RelatedCaseInfoDto { FirstCaseId = rc.FirstCaseId, FirstCaseName

问题 I have to support multiple languages in production application. There are lot of Entity Framework queries that gets data from database as deferred IQueryable list like this: public IQueryable<Request> GetDeferredRequests() { return _dbContext.Set<Request>(); } POCO class looks like this: public partial class Request { public int RequestID { get; set; } public string StatusName { get; set; } public string RequestType { get; set; } } Data Transfer Object looks like this: public class RequestDTO

问题 I need to use DbContextTransaction in a class on a .Net Standard library, I haven't been able to find the corresponding nuget package, I am porting this https://github.com/mehdime/DbContextScope/tree/master/Mehdime.Entity to .Net Core, but I only have 2 compilation errores due to missing packages/dependencies which I am not sure how to find: Error CS0246: The type or namespace name 'MarshalByRefObject' could not be found (are you missing a using directive or an assembly reference?) (CS0246)

问题 At http://msdn.microsoft.com/en-us/library/dd468057.aspx I read that all navigation properties for which I would like to have a change tracking proxy need to be public and virtual . From what I understand, the CLR creates subclasses of my POCOs dynamically, and it re-implements the properties to provide the requested behaviour. For this I undertand that the property needs to be virtual , and that it should have protected or higher accesability. However, if I want to use these for convenience