entity-framework-6

问题 I am using an ASP.NET MVC 4 application with Entity Framework. I want to pass null values conditionally, let's say if pass value into DeptID then it should list of values for only passed DeptID , and if pass DeptID = NULL then it should it all the departments. I wrote a procedure by checking DeptID and it returns the desired output (if DeptID is null , then all rows are returned). But problem is to when I want to pass null values through following code of Entity Framework it is not working.

问题 I have set up a new project in VS 2017. My intention is to use EF CodeFirst approach. So far I used Azure SQL Database, while in this test project I want to use my remote MySQL database. I have created the user and permissions are set just right. This remote database server is accessible to me over MySQL Workbench. I have created a new blank MVC project and through Nuget I installed MySQL.Data.Entity (version 6.9.10). My Context class: [DbConfigurationType(typeof(MySqlEFConfiguration))]

问题 I have a generic Update method for Entity Framework in an abstract DatabaseOperations<T,U> class: public virtual void Update(T updatedObject, int key) { if (updatedObject == null) { return; } using (var databaseContext = new U()) { databaseContext.Database.Log = Console.Write; T foundEntity = databaseContext.Set<T>().Find(key); databaseContext.Entry(foundEntity).CurrentValues.SetValues(updatedObject); databaseContext.SaveChanges(); } } However, this does not handle many-to-many relationships.

问题 Simple question - I'm working in Visual Studio 2017 and while I know that the 'database first' approach in EF is gone, I'm wondering what the replacement is. What I specifically would like to do is generate classes from an existing database. I see this: EntityFramework Reverse POCO Generator - is this the right option, or is there something in VS2017 I should be using? I would think that this would be obvious information, maybe I'm looking in the wrong place... Note: I have an ASP.NET Core

问题 I enabled the migration, and I code the seed codes like follow: protected override void Seed(DbContext c) { c.DbSet<Table1>.AddOrUpdate(..); c.DbSet<Table2>.AddOrUpdate(..); c.DbSet<Table3>.AddOrUpdate(..); } I need the table1 run in order, because the table2 references table1, and the table3 references table1 and table2. but the EF6 has optimized the code generated T-SQL batchs, they query the table1 for table3's references, and there is nothing due to table1 hasn't initialized yet, and EF6

问题 Okay so I am using Entity Framework 6.1 and attempting code first with seeding. I have a drop always intializer that ALWAYS WORKS. However I want to use database migration which I have set up and it works. UNTIL I normalize out a table and then try to seed it I get a primary key error. Basically in my context when I uncomment out the changes in the 'TODO' section and the schema changes I get a primary key violation when attempting population of the newly normalized out table. It will work for

问题 I am using dbcontext Code first to get a query base on this condition for the Classes (tables) below: Creator != null && ArticleAttached != null && !IsCancelled Problem : How to get data from the classes (tables) and show Article Title, No. of Likes, No. Of Comments, Total Assigned, TotalResponded A) I use dbcontext as follows: var ListArticles = dbcontext.LearningActivites .Where(la => la.Creator != null && la.ArticleAttached != null && !la.IsCancelled) .Select(la => new { Id = la.Id, Title

问题 I'm trying to use IDbInterceptor to time Entity Framework's query executions, as accurately as possible, implementing a variant of Jonathan Allen's answer to a similar question: public class PerformanceLogDbCommendInterceptor : IDbCommandInterceptor { static readonly ConcurrentDictionary<DbCommand, DateTime> _startTimes = new ConcurrentDictionary<DbCommand, DateTime>(); public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext) { Log(command,

问题 I have been doing a lot of research on Paging and I am stuck between two methods. With both approaches I will be using PagedList.MVC to display my pages, however the problem lies in how do I pass the data to the PagedList and which of my two methods is more efficient. The best example I have found out there is as follows: public static PagedList<Customer> GetPagedCustomers(int skip, int take) { using (var context = new AdventureWorksLTEntities()) { var query = context.Customers.Include(

问题 I'm using EF 6 and when I run Update-Database it is trying to apply every migration since the beginning of the project, even though there is only migration that is new. If I attempt to create an empty migration, I get an error that says I can't create a new migration because there are explicit migrations pending. The only blog post I found with a similar issue suggested dropping the __MigrationHistory table and doing Update-Database -Script , stripping out all the actual DB changes but