Data topics

Entity Framework DB permissions

LouisT — Mon, 16 Mar 2026 12:32:28 GMT

I want to use Entity Framework with a .Net 9 app but have had difficulty finding information on what DB permissions it needs in the app database.

I've found a couple old StackOverflow posts but having created a user with the recommended db_datareader, db_datawriter and db_ddladmin and updated the app connection string to use it and now the app won't start.

What more does it need?

Problem with the startswith function in NET 9

gusartadv — Thu, 03 Jul 2025 21:55:58 GMT

Hi everyone, I have this request with Odata:

http://localhost:5194/NationalStates?$filter=startswith(state, 'NE')

This works correctly up to version 8.0.14 for the following packages:

MySql.EntityFrameworkCore
Microsoft.Extensions.DependencyInjection.Abstractions
Microsoft.EntityFrameworkCore
among others...

When I update these packages to version 9.0.0 or later, they stop working and give an internal mapping error.

Any clues about this?

EF CORE 8 failed to connect sqlite database file for .net web app in linux server

developship — Wed, 30 Oct 2024 13:25:56 GMT

it created a dbcontext with no tables in memory but did not go to connect the existing database file. How can make ef connect the database file like in the windows?

EF Core display up to date data on predefine delay

Alex_is_programming — Thu, 03 Oct 2024 22:27:54 GMT

Hi,

I have a C#/WPF project for which I use EF Core (database first) to transact with an SQL database. I am struggling with retreiving fresh data from the server on a predefine delay to be displayed on a dashboard.

Scenario is this:

I have an entity call Cars.

Cars has a property that is a virtual ICollection of ToDo call lstToDo

Each ToDo entity has a boolean property call Completed.

The data of SQL database can be modified by many users.

The dashboard is the application running on a computer that no one is using, and that need to display the latest data from the database every X minutes.

So in my scenario everything is working fine except that whenever the property Completed is change, in the database, from false to true (or vice-versa) I am unable to get the new value. I tried using Eager Loading but without any luck.It will catch when a new row has been added to the table, but not when a change happen in an existing row.

The eager loading I use:

myContext.Cars .Include(c => c.lstToDo) .Load(); myCollectionViewSource.Source = myContext.Cars.Local.ToObservableCollection();

Also, in my context I configured it to use LazyLoading.

Any suggestion will be more then welcome

Entity framework core 8 return double quote in Oracle Query

tomtom2x — Thu, 03 Oct 2024 07:12:35 GMT

Hi All,

My project using .net core 8, when i debug code, always get error ".net core ORA-00942: table or view does not exist" i would like to show data using this query:

var data = _db.employee.ToQueryString();

when i debug, the data variable show this:

SELECT "e"."id", "e"."empolyee_name", "e"."employee_code" FROM "employee" "e"

My Question:
how to remove double quote " in EF query to this? SELECT e . id , e . empolyee_name, e . employee_code FROM employee e.

i assume the error table or view does not exist because my EF query returning double quote "".

how to solve it?

thanks & regards.

Cannot connect to LocalDB (provider: Named Pipes Provider, error: 0 - No process is at the other end

BetterToday — Tue, 24 Sep 2024 22:18:12 GMT

I'm trying to manually connect to LocalDB (both, SQL Server 2019 and SQL Server 2022 services) creating a new application database using ADO.NET (Microsoft.Data.SqlClient).

Everytime I try to connect, I get a generic error telling me that the database file could not be attached.

Error.log:

2024-09-17 19:30:18.40 Logon Error: 15350, Severity: 16, State: 1.
2024-09-17 19:30:18.40 Logon An attempt to attach an auto-named database for file C:\Temp\CvTest.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
2024-09-17 19:31:02.66 Logon Error: 15350, Severity: 16, State: 1.
2024-09-17 19:31:02.66 Logon An attempt to attach an auto-named database for file C:\Temp\CvTest.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.

Debugging into the Microsoft.Data.SqlClient source code, the following error turned out to be the real reason behind the issue:

A connection to the server could be established, but an error occurred during the
login process. (provider: Named Pipes Provider, error: 0 - No process is at the
other end of the pipe).

What is causing this error?

This is my simple test connection setup. It's a cheap connection string that every Microsoft sample is quoting:

using SqlConnection con = new SqlConnection(@"Data Source=(LocalDb)\MSSQLLocalDB;Integrated Security=SSPI;MultipleActiveResultSets=True;AttachDBFilename=C:\Temp\CvTest.mdf");
con.Open();

So, it should work off the cuff. But it doesn't.

Using SSMS, I can easily connect to the LocalDB instance and create/delete databases promptly, even with the provided path.

I already updated from MsLocalDb 15 to MsLocalDb 16, but to no avail.

C# & EF Core : 2 databases with a Customertable and different Columns

pwendel — Thu, 01 Aug 2024 13:48:42 GMT

Hello,

I have a little PRoblem with my DbContext.

For Example: I have two Databases both have a Table Customer. One of the Customers has an Extension of our Software so in the Customertable there are for example 3 more columns.

Now when i create the DataAccess Class of the Customer Table i add the Structure from the Customer Table and the 3 extra columns. Now when i Request a Customer for the Customer with the extra Columns all is fine. The Request for the other Customer gets an Error that the last 3 Columns from the Model are not in the Table.

Unfortunately it is not possible to add the Columns to the other Customer Table.

so my Question is: Is there another Way to geht Records from both Databases with one Model Class and one DBContext?

I tried NotMapped and Required in DbContext, I tried Raw SQL but nothing worked. The only Solution is to create 2 DbContexts. But in Our Database there are more such Combinations of Table with different Columns.

Can anyone help or provide a way to test?

Best Regards

Philipp

.NET solution generator

goran — Mon, 01 Jul 2024 16:07:21 GMT

We have released a free version of our product //entity.services that allows you to generate .NET solutions (including the fully customizable source code) based on simple definitions of your data models. You can find a quick start guide on the GitHub page https://github.com/axlln/es-quick-start

Please try it and let us know what you think

Thanks,

Goran

EF Core : foreign key column with same name as existing navigation property

Ricardo Peres — Mon, 20 May 2024 13:59:29 GMT

I want to use EF Core to map a legacy database. I cannot scaffold as there are hundreds of tables and I am only interested in very few and besides scaffolding generates names for the navigation properties which are not the ones I want. The situation is: I have a required many-to-one relationship linked by a column name that matches the name of the property that I want to give.

The code (simplified) is:

public class EntityProperty
{
    public ControlType ControlType { get; set; }
} 

public class ControlType
{
    public List<EntityProperty> Properties { get; set; } = new List<EntityProperty>();
}

Nothing more is required, eg, I'm not using foreign key properties, just navigation.

The problem is, the foreign key column from the EntityProperties table to the ControlTypes is also called ControlType.

So, when I try to map it as:

builder.HasOne(x => x.ControlType)
       .WithMany(x => x.Properties)
       .IsRequired()
       .HasForeignKey("ControlType");

I want to use EF Core to map a legacy database. I cannot scaffold as there are hundreds of tables and I am only interested in very few. The situation is: I have a required many-to-one relationship linked by a column name that matches the name of the property that I want to give.

The code (simplified) is:

public class EntityProperty
{
    public ControlType ControlType { get; set; }
} 

public class ControlType
{
    public List<EntityProperty> Properties { get; set; } = new List<EntityProperty>();
}

The problem is, the foreign key column from the EntityProperties table to the ControlTypes is also called ControlType.

So, when I try to map it as:

builder.HasOne(x => x.ControlType)
       .WithMany(x => x.Properties)
       .IsRequired()
       .HasForeignKey("ControlType");

I get the following exception:

InvalidOperationException: The property or navigation 'ControlType' cannot be added to the 'EntityProperty' type because a property or navigation with the same name already exists on the 'EntityProperty' type.'

The problem is with HasForeignKey, I guess it's because I am adding a shadow property when a "physical" property already exists, but I what I really mean to say is to use a different column name to link the two entities: what I want is to be able to specify a "not standard" column name for the foreign key, which I am not able to. I do not have a foreign key property, only a navigation property, and I do not want to have one.

Can I ignore a single return value when multiple values are returned?

primem0ver — Sat, 04 May 2024 21:49:14 GMT

Some time ago, the ability to create a function which has multiple return values was created. Yes, I know this can be avoided by using out... but I was curious. In traditional method calls, the return value can be ignored by not assigning the return value to a variable. I recently decided to use multiple return values in a new method because I wanted to avoid having to worry about the method call when the return value isn't always used. Turns out that may have been an oversight on my part, since I as far as I know, I still have to define a return value. For example, if the return signature of "MyFunction" is (int, bool) and I don't need the bool value, I still have to define it (FAIK... which is the point here):

private (int, bool) MyFunction(...) { bool error = false; int someReturnValue = 0; //... does something and sets error if there is a problem return (someReturnValue, error); } public void MyUnconcernedCallerFunction() { int ret; bool error; // what if I don't need to worry about the error here? (ret, error) = MyFunction(...); }

is there currently any convention that allows me to not declare the bool error value if I don't need it? (i.e. can I ignore the bool part of the return?)

SIDE NOTE: Why isn't there a general forum here? While my example is language specific, the question isn't. This is just a general .NET question having to do with data and there are no general options in the "Choose a Label" options. I couldn't post without choosing one so I just picked the one that made the most sense.

"Thread was interrupted from a waiting state" from DbConnectionPool.CleanupCallback

Pedro-Goncalves — Wed, 30 Aug 2023 11:23:14 GMT

Hi,

I'm getting this error, and I'm not able to fix it, or even understand from where it comes.

I'm also sure that all my SqlConnection are instanciated with Using (VB.NET), so the Dispose should be called for every one.

Does anyone have an idea about the cause?

This error started after upgraded the app to the .NET Framework 4.8.1, from 4.6.2. Maybe it's a coincidence...

Source: mscorlib; Message: Thread was interrupted from a waiting state.; Data:; StackTrace: at System.Threading.WaitHandle.WaitOneNative(SafeHandle waitableSafeHandle, UInt32 millisecondsTimeout, Boolean hasThreadAffinity, Boolean exitContext)

at System.Threading.WaitHandle.InternalWaitOne(SafeHandle waitableSafeHandle, Int64 millisecondsTimeout, Boolean hasThreadAffinity, Boolean exitContext)

at System.Threading.WaitHandle.WaitOne(Int32 millisecondsTimeout, Boolean exitContext)

at System.Data.ProviderBase.DbConnectionPool.CleanupCallback(Object state)

at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)

at System.Threading.TimerQueueTimer.CallCallback()

at System.Threading.TimerQueueTimer.Fire()

at System.Threading.TimerQueue.FireNextTimers();

Regards,

Pedro

Subject: Help & Support Case for ADO.NET Entity Framework back end changes & front end changes with

ABHAY_SAKUNDE — Mon, 08 May 2023 21:51:11 GMT

sync to Model & Database respectively.

Help & Support Case

From,

Abhay Sakunde,

Cognizant India Pvt. Ltd. Pune

Project Team: MWS CWS Apps Team

E-mail ID: (email removed for privacy reasons)

Mobile No.: (phone number removed for privacy reasons)

To,

The Manager,

Human Resources Or Development Team,

Microsoft India Pvt. Ltd. Pune

Subject: Help & Support Case for ADO.NET Entity Framework back end changes & front end changes with sync to Model & Database respectively.

Hi Team,

Initially using Entity Workflows: Program / Model / Database Priority, we do the design of ADO.NET Entity Data Model & development of database. But once initial process is done if any changes occur either as back end changes into database or front end changes into model then how we can manage or do synchronization between ADO.NET Entity Data Model & Database? How it is done with respect to different type of Entity Workflows i.e. Program / Model / Database Priority?

There are following options like

Update Model From Database
Generate Database From Model

In case of Entity Workflows - Model Priority, Initially Model is designed & database is generated. Now if model is changed only then option Generate Database From Model will work either to update existing database or new Database will get created? Please Clarify.

In case of Entity Workflows - Database Priority, Initially database exists & model design is generated.

Now, if model is changed only then option Generate Database From Model will work either to update existing database or new Database will get created? Please Clarify.

Waiting for reply.

Please let me know if any detail information required for mentioned feature.

Screens:

[1] Model & Database Options

Thanks & Regards,

Abhay Sakunde

Entity Framework core

杰西2110 — Wed, 01 Feb 2023 05:52:41 GMT

Different instances of dbcontext, savechanges affect each other

Initializing TwitterClient To Access Twitter API

JeunesseAfricaine — Thu, 22 Sep 2022 15:04:20 GMT

Hi, I keep on getting this error; " while trying to access the Twitter API using the TwitterClient. The Client builds successfully but then it shows this error when I run: dotnet run

Access Restrictions and Parties Conflict

FireTeam — Mon, 29 Aug 2022 04:07:09 GMT

First question:Where to find information about the archive of data on a global database attack and including threat flows with a full description of the place in and out of, time, participation, solution and other actions.
Second question: After answering the first, if an error or falsification of the problem or intentional deception is detected, further actions and the possibility of restoring Russia in the common process, common problem and situation in the world together
Third:Thanks in advance for the decision

Types of sdk in .net 6 and their difference

Darshan1385 — Wed, 20 Jul 2022 11:01:16 GMT

Hi
Can we know the difference between these 3 sdk versions in .net 6.0.5

1) SDK 6.0.300
2) SDK 6.0.203
3) SDK 6.0.105

Also if we install SDK 6.0.300 over SDK 6.0.101 ,we will be able to see two versions in control panel . So can you please let us know the difference between these 3 version (SDK 6.0.300,SDK 6.0.203,SDK 6.0.105) of SDK

关于文件读取

niezheti — Sun, 08 May 2022 16:40:36 GMT

大家好：

请问一下，假如一个文件夹里有上万的文件，当我开发程序，使用方法创建一个文件流时，传入文件的路径，系统找到这个文件是否需要遍历这上万的文件才找到目标文件？

hello everyone:

Excuse me, if there are tens of thousands of files in a folder, when I develop a program and use the method to create a file stream, the path of the incoming file. Does the system need to traverse the tens of thousands of files to find the target file?

SQL Sever and Apache Log4 vulnerabilities

VickyO532 — Tue, 18 Jan 2022 04:34:29 GMT

We use SQL Server 2014 Management Studio, and SQL Server 2015 Reporting Services (SSRS?) on a server that is not owned by us. The operating system is Windows Sever 2012 R2.

I did not set up our SQL server.

An MS article I found says:

SQL Server (on Windows) – all editions

Note: If a customer installs Java support and deploys Java Archives (JARs) that depend on the Log4j 2 library, they are advised to upgrade to the latest version or remove the Java Archives (JARs) that require the dependency.

Source: https://msrc-blog.microsoft.com/2021/12/11/microsofts-response-to-cve-2021-44228-apache-log4j2/

How do I check if we have installed Java Support? How do I check if we use Java Archives (JARs)?

Appreciate any leads.

How do create a matrix formula to calculate in all range (B:F) with this rare condition.

dpparner — Mon, 17 Jan 2022 20:26:40 GMT

Bom dia família,

Preciso criar uma fórmula matricial para calcular quantas vezes essa coincidência aparece em todo o intervalo B:F , de acordo com essas condições ( A) na primeira linha ), ( M) na segunda linha ). Tentei com essas 2 fórmulas, mas conta apenas uma coincidência. Alguém tem alguma sugestão por favor?

Desde já, obrigado.

Window Service and ODP.NET Managed Driver

edisonpebojot — Mon, 06 Dec 2021 05:25:42 GMT

So, I am creating a Windows Service using the .Net Framework, the problem is, the ODP.Net Managed Driver woke up in the Application Console, but when I converted it to Windows Service, the ODP.Net Managed Driver did not works and it doesn't. reading from Oracle Database.