How to perform SUM operation in Entity Framework

Entity Framework 6 Code First From Database context performs CREATE TABLE on existing an VIEW

We have a production Oracle database server maintained by our ERP partner....For some custom development I need to connect to this Oracle database using Entity Framework 6. I have a user that can SELECT any table on the ERP schema and I create views in the schema/user used in my EF context....The view itself is pretty straightforward, a few joins b...

Could EntityState.Modified cause Insert operation to be performed

DbContext.Entry... method is used to do an ...explicit loading..., that means that It gives you access to all the information that the DbContext has about an entity. This goes beyond the values that are stored in the properties of the actual entity and includes things such as the ...state of the entity... and the original values for each property w...

Perform two related operations in EF Core

Is ...Class.Id... is autoincrement/sequence field? May be EF is querying DB for it's value after insertion... Try add ...Console.WriteLine(Class.Id)... or ...await Context.Entry(Class).ReloadAsync()... after first save.

Workaround needed for EF Core performing GroupBy operations in memory instead of in SQL

As @xanatos points out, this is is not supported in EF Core 1.1.0 (and not even 2.0.0). There is, however, a workaround, using literal SQL:...var q = db.MyTable .FromSql("select t.* from " + " (select distinct Field1 from MyTable) t0 " + "cross apply " + " (select top 1 t.* from MyTable t...

Perform LINQ in Entity Framework core to load sub-related entities Data

I am working on .NET Core application with Entity Framework Core. I have three tables Questions, Answer and AnswerType so schema is as ...question <-- 1:* --> Answers <-- 1:1--> AnswerTypes ...I need to run query that return questions with ICollection of Answer , further Answer with AnswerType... Question...public class QuestionDataModel { ...

How to resolve: The transaction operation cannot be performed Exception

I am getting this error, and I have not been able to resolve:...System.Data.SqlClient.SqlException: 'The transaction operation cannot be performed because there are pending requests working on this transaction.'...What is going on is that a usual data operation is taking place as part of a Controller Action....At the same time, there is a Filter th...

Is it possible to perform a SQL Injection on a application that uses Entity Framework?

Heed this:...It is quite easily possible if the developer uses EF as a wrapper around ADO.NET and uses FromSQL. Of course, this is not the intended nor normal use of EF, but I have seen it – Camilo Terevinto...REF: ...Raw SQL Queries...Additionally, while not really "sql injection", since one of the goals of such is to somewhat alter your dat...

C# awaited entity framework core in memory operation is very slow when performed within loop

I have this kind of code that I am trying to unit test with an in memory ef core database....public async Task<int> UpdateHistoricalWeatherDataAllLocationsAsync() { var regions = DalContext.Region.ToList(); var allInsertAmounts = new List<int>(); foreach (var region in regions) { var startDate = Dat...

Update entity error: A second operation started on this context before a previous operation completed

When I update the entity, I got the error in the controller ...A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread safe....Code:...public class MyController: Controller { private readonly DbContext _db = new DbContext(); ...The method is...[HttpPatch] [Route("MyRo...

Perform a single query based on comparison of sum of child collections

I have the following classes... public class Order { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int Id { get; set; } public DateTime Date { get; set; } public decimal TotalPaid { get { return Payments.Sum(x => x.Amount); } } public decimal Total { get { return OrderItems...