Questions tagged [entity-framework-core]
For questions about Entity Framework Core (EF Core) for .NET Core. Please also add a version-specific [ef-core-xx] tag, when applicable. Note that Entity Framework for .NET Framework is an older, different product that fits the [entity-framework] tag.
entity-framework-core
22,727
questions
546
votes
18
answers
404k
views
Command dotnet ef not found
I'm following the docs in order to create an initial migration. When I execute dotnet, I get the help section, meaning that the PATH works properly.
Then I try to execute the command below from the ...
- 37.9k
462
votes
20
answers
600k
views
How to unapply a migration in ASP.NET Core with EF Core
When I run PM> Remove-Migration -context BloggingContext in VS2015 with an ASP.NET Core project using EF Core, I get the following error:
System.InvalidOperationException: The migration '...
- 23.3k
384
votes
36
answers
403k
views
Entity Framework Core: DbContextOptionsBuilder does not contain a definition for 'usesqlserver' and no extension method 'usesqlserver'
I am new to EF core and I'm trying to get it to work with my ASP.NET Core project.
I get the above error in my startup.cs when trying configure the DbContext to use a connection string from config. I ...
- 3,986
324
votes
11
answers
321k
views
Entity Framework Core add unique constraint code-first
I can't find way to add a unique constraint to my field with using attribute:
public class User
{
[Required]
public int Id { get; set; }
[Required]
// [Index("IX_FirstAndSecond", 2, ...
- 3,295
287
votes
26
answers
378k
views
The term "Add-Migration" is not recognized
I'm using this MSDN Tutorial to run in VS2015 the command PM> Add-Migration MyFirstMigration -context BloggingContext that ran yesterday successfully but today it's giving the following error that ...
- 23.3k
278
votes
15
answers
176k
views
Need to Update EF Core Tools
When I use the dotnet ef tools in the VS 2017 Package Manager Console I get a warning message about needing to update EF Core tools:
PM> dotnet ef migrations list -s ../RideMonitorSite
The EF ...
user4266661
264
votes
22
answers
335k
views
Raw SQL Query without DbSet - Entity Framework Core
With Entity Framework Core removing dbData.Database.SqlQuery<SomeModel> I can't find a solution to build a raw SQL Query for my full-text search query that will return the tables data and also ...
- 2,823
226
votes
22
answers
295k
views
.NET Core 3.0 possible object cycle was detected which is not supported
I have two entities that are related as one-to-many:
public class Restaurant {
public int RestaurantId {get;set;}
public string Name {get;set;}
public List<Reservation> Reservations {...
- 2,363
212
votes
10
answers
203k
views
Get SQL code from an Entity Framework Core IQueryable<T>
I am using Entity Framework Core and I need to see which SQL code is being generated. In previous versions of Entity Framework I could use the following:
string sql = ((System.Data.Objects....
- 38.5k
186
votes
7
answers
199k
views
How to auto create database on first run?
My application being ported to .NET Core will use EF Core with SQLite. I want to automatically create the database and tables when the app is first run. According to documentation this is done using ...
- 5,230
174
votes
7
answers
211k
views
Can I generate script of a migration with EF code first and .net core
I'm building a MVC application with .Net Core and I need to generate the script of a migration.
With EF6 I did run the command
update-database -script
but when I try to do the same with .net Core is ...
- 4,503
174
votes
9
answers
131k
views
Filtering on Include in EF Core
I'm trying to filter on the initial query. I have nested include leafs off a model. I'm trying to filter based on a property on one of the includes. For example:
using (var context = new ...
- 8,194
167
votes
2
answers
69k
views
Include several references on the second level
Assume we have this model :
public class Tiers
{
public List<Contact> Contacts { get; set; }
}
and
public class Contact
{
public int Id { get; set; }
public Tiers Tiers { get; set;...
- 3,390
164
votes
16
answers
145k
views
EF Core Mapping EntityTypeConfiguration
In EF6 we usually able to use this way to configure the Entity.
public class AccountMap : EntityTypeConfiguration<Account>
{
public AccountMap()
{
ToTable("Account");
...
- 2,898
163
votes
9
answers
139k
views
How and where to call Database.EnsureCreated and Database.Migrate?
I have a ASP.NET Core 6 MVC application, and I need to call the Database.EnsureCreated and Database.Migrate methods.
But where should I call them?
- 2,281
162
votes
12
answers
303k
views
Unable to create an object of type '[DBContext's Name]'. For the different patterns supported at design time [closed]
I'm following one of Mosh Hamedani Course on ASP.NET MVC in Udemy.
I came across one error while designing my Database using code-first (Entity Framework).
At first, I got the error of " No ...
- 1,651
161
votes
10
answers
357k
views
How to update record using Entity Framework Core?
What is the best approach to update database table data in Entity Framework Core?
Retrieve the table row, do the changes and save
Use keyword Update in DB context and handle exception for item not ...
- 4,038
157
votes
14
answers
108k
views
EntityTypeBuilder does not contain a definition for ToTable in EF Core
I have this sample code:
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using Models;
namespace MySampleNamespace
{
public class MyDbContext : ...
- 12.2k
151
votes
19
answers
245k
views
Entity Framework Core: `SqlNullValueException: Data is Null.` How to troubleshoot?
I am using Entity Framework Core in an ASP.NET Core application and Controller action and I haven't changed something to the working code nor to the database but I can't tell what is the query ...
- 8,775
147
votes
3
answers
80k
views
How to call ThenInclude twice in EF Core?
I'm creating an ASP.NET Core API app, and relying on EF Core. I have entities defined like this:
public class AppUser : IdentityUser
{
public string FirstName { get; set; }
public string ...
- 3,184
144
votes
13
answers
148k
views
How do you show underlying SQL query in EF Core?
At 3:15 from the end of this ".NET Core 2.0 Released!" video, Diego Vega shows a demo of new features in Entity Framework Core 2.0. As part of that, a dump of the underlying SQL is shown in ...
- 29.2k
136
votes
13
answers
163k
views
How to store JSON in an entity field with EF Core?
I am creating a reusable library using .NET Core (targeting .NETStandard 1.4) and I am using Entity Framework Core (and new to both). I have an entity class that looks like:
public class Campaign
{
...
- 2,895
129
votes
24
answers
184k
views
"Build failed" on Database First Scaffold-DbContext
I'm trying to generate classes from a database (EntityFramework's database first approach).
For convenience, I'm more or less walking along with this tutorial:
https://docs.efproject.net/en/latest/...
- 1,469
125
votes
31
answers
179k
views
Your startup project doesn't reference Microsoft.EntityFrameworkCore.Design
I have 2 projects in my solution, I have a project with Entity Framework Core installed:
And in the other ASP.NET Web API project I have these packages:
<?xml version="1.0" encoding="utf-8"?>
&...
- 12k
124
votes
7
answers
33k
views
How can I reset an EF7 InMemory provider between unit tests?
I am trying to use the EF7 InMemory provider for unit tests, but the persistent nature of the InMemory database between tests is causing me problems.
The following code demonstrates my issue. One test ...
- 11.2k
123
votes
23
answers
168k
views
Add migration with different assembly
I am working on a project with ASP.NET CORE 1.0.0 and I am using EntityFrameworkCore. I have separate assemblies and my project structure looks like this:
ProjectSolution
-src
-1 Domain
...
- 1,261
121
votes
2
answers
136k
views
Entity framework EF.Functions.Like vs string.Contains
I was reading the announcement of entity framework core 2.0 https://blogs.msdn.microsoft.com/dotnet/2017/08/14/announcing-entity-framework-core-2-0/
It says that they added new Sql functions like EF....
- 5,048
117
votes
5
answers
128k
views
How to set command timeout in ASP.NET Core / Entity Framework Core?
The place where the command timeout is set is no longer the same as earlier versions.
However, I cannot find anywhere that says how to change this.
What I am doing is uploading very large files which ...
- 36.6k
115
votes
30
answers
132k
views
Unable to create migrations after upgrading to ASP.NET Core 2.0
After upgrading to ASP.NET Core 2.0, I can't seem to create migrations anymore.
I'm getting
"An error occurred while calling method 'BuildWebHost' on class
'Program'. Continuing without the ...
- 1,367
114
votes
16
answers
300k
views
Error: the entity type requires a primary key
I would like to expand the question asked on this thread
Binding listbox to observablecollection
by giving it an ability to persistent the data. The structure is mostly the same except I installed ...
- 3,296
113
votes
5
answers
88k
views
in entity framework code first, how to use KeyAttribute on multiple columns
I'm creating a POCO model to use with entity framework code first CTP5. I'm using the <key()> decoration to make a property map to a PK column. But how can I define a PK on more then one ...
- 6,361
113
votes
21
answers
263k
views
How to run stored procedures in Entity Framework Core?
I am using EF Core 1.0 in an ASP.NET Core App. Can you please point me to the proper way of executing stored procedures? The old method with ObjectParameters and ((IObjectContextAdapter)this)....
- 25.2k
109
votes
5
answers
170k
views
Entity framework Core Update-database specific migration
I am trying to figure out how to run a specific migration from the package manager in nuget.
I have tried to run:
update-database -TargetMigration test32
But I do get this message:
A parameter ...
- 1,633
109
votes
11
answers
77k
views
How to mock an async repository with Entity Framework Core
I'm trying to create a unit test for a class that calls into an async repository. I'm using ASP.NET Core and Entity Framework Core. My generic repository looks like this.
public class ...
- 2,376
106
votes
5
answers
88k
views
navigation property should be virtual - not required in ef core?
As I remember in EF navigation property should be virtual:
public class Blog
{
public int BlogId { get; set; }
public string Name { get; set; }
public string Url { get; set; }
...
- 8,485
101
votes
6
answers
67k
views
ef core doesn't use ASPNETCORE_ENVIRONMENT during update-database
I use visual studio to update all my environments with a certain migration. It had worked fine using the command below.
update-database -Migration initMigrationProduct -c ProductContext -Environment ...
- 2,866
100
votes
10
answers
158k
views
How to update the model when using database first approach
I used EntityFramework Core database first to create model as illustrated in the EF Core documentation
But I don't know how to update the model when the database has been edit.
- 1,103
98
votes
7
answers
116k
views
Mocking EF core dbcontext and dbset
I am using ASP.NET Core 2.2, EF Core and MOQ. When I run the test I am getting this error:
Message: System.NotSupportedException : Invalid setup on a non-virtual (overridable in VB) member: x => x....
- 1,978
93
votes
13
answers
77k
views
ASP - Core Migrate EF Core SQL DB on Startup
Is it possible to have my ASP Core Web API ensure the DB is migrated to the latest migration using EF Core? I know this can be done through the command line, but I want to do it programatically.
- 6,225
93
votes
6
answers
235k
views
Auto-increment on partial primary key with Entity Framework Core
I have declared the following model using the EF Core fluent API:
modelBuilder.Entity<Foo>()
.HasKey(p => new { p.Name, p.Id });
Both fields are marked as the primary key when I create ...
- 2,695
92
votes
10
answers
218k
views
Cannot access a disposed object. A common cause of this error is disposing a context
I have written a simple application and when I navigate to my edit page the below error pops up.
Microsoft.EntityFrameworkCore.Query[10100]
An exception occurred while iterating over the results of ...
- 1,390
92
votes
1
answer
59k
views
AddDbContext or AddDbContextPool
For Asp.net Core apps, which one do we have to use? AddDbContext or AddDbContextPool? According to EF Core documentation, AddDbContextPool provides high performance but the default Asp.net Core ...
- 14.9k
89
votes
5
answers
128k
views
How to instantiate a DbContext in EF Core
I have setup .net core project and db context also. But i cant start using dbContext yet due this error-
"there is no argument given that corresponds to the required formal
parameter 'options'&...
- 1,503
89
votes
19
answers
187k
views
Could not load file or assembly Microsoft.Extensions.DependencyInjection.Abstractions, Version=1.1.0.0
After update to the new package Microsoft.EntityFrameworkCore.SqlServer 1.1.2 I got error when try to create DBContext:
System.IO.FileLoadException occurred HResult=0x80131040
Message=Could ...
- 1,269
88
votes
3
answers
127k
views
What goes into DbContextOptions when invoking a new DbContext?
I am not using DI and simply want to invoke a DbContext from within my controller. I am struggling to figure out what the 'options' should be?
ApplicationDbContext.cs
public class ...
- 5,558
83
votes
1
answer
45k
views
ASP.NET add migration 'composite primary key error' how to use fluent API
Hello I am in the process of creating a Web Application and have already installed both the Microsoft.entityFrameworkCore and Microsoft.entityFrameworkCore.Tools.
During the process of executing an ...
- 4,383
83
votes
3
answers
47k
views
AddAsync() vs Add() in EF Core
Ok multiple questions here:
I am trying to understand what is the difference (outside the obvious
asynchronous) between AddAsync() and Add() methods in EF Core?
When do you choose one over the other?...
- 8,180
82
votes
5
answers
56k
views
How to get Table Name of mapped entity in Entity Framework Core
In some reason, I need to use SQL in EFCore, and I will use table name of mapped entity. How can I get it?
- 1,419
79
votes
7
answers
166k
views
Working with SQL views in Entity Framework Core
For example, I have such model:
public class Blog
{
public int BlogId { get; set; }
public string Url { get; set; }
public BlogImage BlogImage { get; set; }
}
public class BlogImage
{
...
- 5,613
79
votes
2
answers
83k
views
Entity Framework Core: How to get the Connection from the DbContext?
I am trying the new Entity Framework Core with MySQL Connector.
I can get a valid DbContext and write into the database so everything has been setup correctly.
I need to get the Connection from ...
- 2,656