entity-framework-core

问题 I want to seed some data using EntityFramework in .net core 3.1 and I'm facing an issue: I've got two SQL tables (so two DbSet<>): public virtual DbSet<TableA> TableA { get; set; } public virtual DbSet<TableB> TableB { get; set; } Table A has this structure: [Key] public int Id { get; set; } // PK public string EnglishText { get; set; } // some value Table B has this structure: [Key] public int Id { get; set; } // PK public int TableAId { get; set; } // FK to Table A public string

问题 I installed a visual studio 2017 and I have created a MVC project called WebApplication1. In the Dependencies-> NuGet I have the files Microsoft.AspNetCore.App(2.2.0) Microsoft.AspNetCore.Razor.Design(2.2.0). In Dependencies->SDK: Microsoft.AspNetCore.App(2.2.0) Microsoft.NETCore.App (2.2.0) I want to install Entity Framework Core for my project. Thus I right click on my project and select "Manage Nuget Packages" and then in brows section I enter "Microsoft.EntityFrameworkCore.SqlServer" in

问题 I'm building ASP.NET Core Web Api with Simple Injector and have the following problem: The data for each user is stored in his individual base (but with the same schema), which is known only after he authorizes himself. So... I can give DbContext it's proper connection string only after user's authorization. What is the best way to accomplish this? For now I am storing the connection string in HttpContext custom claim and am refering to it with a use of a static helper class in DbContext 's

问题 I'm building ASP.NET Core Web Api with Simple Injector and have the following problem: The data for each user is stored in his individual base (but with the same schema), which is known only after he authorizes himself. So... I can give DbContext it's proper connection string only after user's authorization. What is the best way to accomplish this? For now I am storing the connection string in HttpContext custom claim and am refering to it with a use of a static helper class in DbContext 's

问题 I am using the dotMemoryUnit to prove the my DbContext object is getting garbage collected properly. I feel that this code should work properly in a unit test, but the test always fails. The only thing I can guess is EF Core is holding a reference somewhere. Edit: I'm not sure the suggested question addresses this problem as this is .Net Core and not .Net Framework. The documentation for GC.Collect()'s default is forced and the documentation says nothing about hints. Edit 2: I did find the

问题 I have an IQueryable extension method: public static void SomeExt<T>(this IQueryable<T> query, DbContext context) {...} and I would like to know if there is some way to get DbContext from query so that DbContext argument could be removed leaving only: public static void SomeExt<T>(this IQueryable<T> query) {...} I have tried something like this Access DataContext behind IQueryable but its not working, getting zero fields. Also there is way to get it from DbSet Can you get the DbContext from a

问题 I'm struggling creating a non-nullable/required Owned Type with Entity Framework Core. I'm using EF Core 3.0 against PostgreSQL database. My value object: public class PersonName { public PersonName(string name) { this.Name = name; } public string Name { get; set; } } My entity: public class Person { public int Id { get; set; } public virtual PersonName FullName { get; set; } } My entity configuration: public void Configure(EntityTypeBuilder<Person> builder) { builder.ToTable(nameof(Person));

问题 I'm struggling creating a non-nullable/required Owned Type with Entity Framework Core. I'm using EF Core 3.0 against PostgreSQL database. My value object: public class PersonName { public PersonName(string name) { this.Name = name; } public string Name { get; set; } } My entity: public class Person { public int Id { get; set; } public virtual PersonName FullName { get; set; } } My entity configuration: public void Configure(EntityTypeBuilder<Person> builder) { builder.ToTable(nameof(Person));

问题 In my App, I have some data which are stored on different databases (e.g. identity and User Info are stored separately to Content-related stuff for historical reasons). However I would like to be able to get advantage of the '.Include' method of EF Core, but as the data is stored in a different DB, is there a way to query two databases in the same DbContext? 回答1: One option I am seeing is to use views to get all the information from the 2nd database back to the local database. If using SQL

问题 I have following query within my project and it is consuming lot of time to execute. I am trying to optimize it, but not able to successfully do it. Any suggestions would be highly appreciated. _context.MainTable .Include(mt => mt.ChildTable1) .Include(mt => mt.ChildTable1.ChildTable2) .Include(mt => mt.ChildTable3) .Include(mt => mt.ChildTable3.ChildTable4) .SingleOrDefault( mt => mt.ChildTable3.ChildTable4.Id == id && mt.ChildTable1.Operation == operation && mt.ChildTable1.Method = method &