issues in defining relationship between entities in EntityFramework core code...
Hi Aall,I am completely new to Entity framework, working on sample app.Following the .entity framework CodeFirst approach for asp.net core web apiwe created two entities public class Account { public...
View ArticleNumber of rows returned by a DataReader
Hi, Is there any way to know how many rows the data reader returns after executing a SQL statement? For now, I am doing the follwing:if datareader.hasrows then while datareader.read count += 1 end...
View ArticleCan't migrate Entity Framework
HiI run this command on package manager console :pm>add-migration FirstAppDemobut keeping get this image:The project first app demo failed to build.What should I do?please inform.regardsSaeed
View ArticleIs there a way to get a link query to return a row from a table?
So I am trying to access a database table that has a field that I need to match and if there is a match I need to select data out a field in that table. I have tried and few things and I am coming up...
View ArticleLINQ and Entity Framework errors
I have two tables in SQL database:Challenger (ChallengerID, FirstName, LastName, Email) Rank (RankID, ChallengerID, Best, DateAcheieved) and using entity framework to access data. When I am trying to...
View ArticleHow to use Clause "IN"
Hi All,How can I passed array companies id into the .Where highlight orange query below:-var companies = companies.Where(c=>!c.Id.Equals(0)).Select(c => c.Id).Distinct().ToList();...
View ArticleSum and Case to linq
Need help to convert sql to linq in c#SELECT SUM(CASE WHEN Evaluation.StatusId = 3 THEN 1 END)AS EvalutionOK, SUM(CASE WHEN Evaluation.StatusId = 4 THEN 1 END) AS EvalutionTodo,...
View Articlelistbox does not show the data
public DataTable getCourses() { string CS = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString; using (SqlConnection con = new SqlConnection(CS))...
View ArticleexecuteScalar method is giving error
Hi All,public string execCount(string query) { string CS = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString; using (SqlConnection con = new...
View ArticleWalking into an antipattern? Fetching data multiple FKs many layers deep ...
Using SQL and EF Core, I need to efficiently fetch data scattered across many tables.There are ~50 tables, with many tables having multiple FK relationships, and the layers of FK relationships run up...
View ArticleEF Core 5.0.X Model Customizations - database first
I am modernizing a 4.X aspnet app to Blazor Server/Wasm.In the original app I was using EF 6.4.X and a whole bunch of model customizations. Been looking for how I can stil use these but all I find is...
View ArticleEditing SQL database items and Model Binding attributes?
Problem: I want to update an SQL database record and not create a new database entry.The ASP.Net Core MVC application I am working on involves inventory tracking. Data are stored in an MS SQL server...
View ArticleLinq GroupBy and Sum - .First() could not be translated
My data is owner, location, date, charge, payment, the plan is to get a list of owners, each having a location, and the Sum OwnerTotal (charge - payamount)OwnerIdLocationChargePayAmount1Loc 110001Loc...
View ArticleEF Core 5 - Does the order of Include()/Where() methods in queries matter?
I am upgrading from .NET Core 2.2 to .NET 5.0 one major release at a time (2.2 -> 3.0 -> 3.1 -> 5.0), and I have a LINQ query into a MySQL database that works differently after the upgrade to...
View ArticleHelp retrieving columns from StoredProcedure using LINQ...
I need to retrieve data by using a stored Procedure using MVC LINQ. I need to retrieve two fields from the table.My method is a public async Task IEnumerable and inside the body needs to return two...
View ArticleHelp with composing async Task .....
I must select distinct values from one column named YEAR from the database table. I MUST use async Task<IEnumerable<variables>> for this code in my class library.I need help with the body...
View ArticleScaffold common base class for all entities
Creating ASP.NET 5 Core MVC application using Npgsql EF Core provider. Scaffold creates Poco classes like namespace MyDbContext { public partial class Customer { public Customer() { } public string Id...
View ArticleSeeding users using UserManger and Identify role class thinks its a static class
I am trying to seed users and permissions but no matter what I do I get the following error.But when you look below at my code not one method is a static method so why on earth is visual studio...
View ArticleEF Core, first query is slow, how to generate a precompile view to improve...
Hi,I am working on webapi 3.1 with entityframework core 3.16. I got about 180 entity that is slow with the first query. I read that precompiled entityframework view can help improve performance. I...
View ArticleThe instance of entity type cannot be tracked because another instance with...
The instance of entity type 'Table' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked. When attaching existing entities, ensure that only one entity...
View Article
![[-100%] Commodity Intelligence – (Android Apps)](http://play-lh.googleusercontent.com/j67-qJvmnn4xnVlYVZ9ZhtZUJIgwjKekJGoKQT6D1KHcWGZxtQaFroummEvwV17na7tyh1pGbbeWCRdWtTKqeg=w950-h950)
