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Thank you for the reply, Richard.

The difficult we do right away...
...the impossible takes slightly longer.

A concurrent dictionary loaded ordered is essentially an ordered list.

Whether you handle it as KeyValue pairs or as .Values is another matter (maybe).

"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I

Yeah, that's what I've settled on doing - using ConcurrentDictionary's.

Thanks for your reply. Smile | :)

The difficult we do right away...
...the impossible takes slightly longer.

I'm using EF 6 Core Code First. I'm trying to set up some basic code and I'm getting an exception at runtime.

Here's my Context class:

using Microsoft.EntityFrameworkCore;

namespace EFCoreDBFirstExample.Models
{
    public partial class ModelContext : DbContext
    {
        public virtual DbSet Departments { get; set; }
        public virtual DbSet Employees { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            var connectionString = @"Server=MAROIS_KEVIN_1\SQLEXPRESS;Database=Test;Trusted_Connection=true;Encrypt=false;";
            optionsBuilder.UseSqlServer(connectionString, options => options.EnableRetryOnFailure());
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity(entity =>
            {
                entity.ToTable("Departments", "public");

                entity.HasKey(e => e.DepartmentId)
                      .HasName("DeptartmentId");

                entity.Property(e => e.DepartmentId)
                      .HasColumnName("DeptartmentId");

                entity.Property(e => e.DepartmentName)
                    .HasColumnName("DepartmentName")
                    .HasColumnType("varchar")
                    .HasMaxLength(30);
            });

            modelBuilder.Entity(entity =>
            {
                entity.ToTable("EmployeeName", "public");

                entity.HasKey(e => e.EmployeeId)
                      .HasName("EmployeeId");

                entity.Property(e => e.EmployeeId)
                      .HasColumnName("EmployeeId");

                entity.Property(e => e.EmployeeName)
                    .HasColumnName("EmployeeName")
                    .HasColumnType("varchar")
                    .HasMaxLength(30);
            });
        }
    }
}

Here's how I'm using it

using EFCoreDBFirstExample.Models;

using (var db = new ModelContext())
{
    // Creating a new department and save it to the database
    var newDept = new Departments();
    newDept.DepartmentId = 1;
    newDept.DepartmentName = "Development";

    db.Departments.Add(newDept);
    var count = db.SaveChanges(); //<======================= ERROR HERE

    Console.WriteLine("{0} records saved to database", count);

    // Retrieve and display the data
    Console.WriteLine();
    Console.WriteLine("Departments:");
    foreach (var dept in db.Departments)
    {
        Console.WriteLine($"{dept.DepartmentId}: {dept.DepartmentName}" );
    }

    Console.ReadLine();
}

Here's the exception:

Microsoft.EntityFrameworkCore.Storage.RetryLimitExceededException
  HResult=0x80131500
  Message=The maximum number of retries (6) was exceeded while executing database operations with 'SqlServerRetryingExecutionStrategy'. See the inner exception for the most recent failure.

Inner Exception 1:
SqlException: Cannot open database "Test" requested by the login. The login failed.
Login failed for user 'MAROIS_KEVIN_1\kevin'.

As you can see, I'm using Trusted Connection in my connection string. Not sure why EF is trying to connect with the user 'kevin'.

I could use some help here. Thanks

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Where did it get "kevin" from? That's the account you logged into Windows as. "Integrated Security" means use the Windows account the code is running as.

The error message is blatantly obvious: "Cannot open database "Test" requested by the login. The login failed.
Login failed for user 'MAROIS_KEVIN_1\kevin'."

You SQL Server doesn't know who "kevin using a Windows Account" is. You have to go into SQL Server Manager to correctly setup a Windows Login account in your SQL Server Security and give it appropriate permissions to the database and tables as appropriate for your situation.

If you haven't created the database yet and are relying on EF to do it for you, you have to give your account admin permissions to the SQL Server so YOU can create databases on the server.

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Dave Kreskowiak

Yes, Kevin is my Windows login, but all my other apps use Trusted Connection without a user specified.

connectionString="Server=MAROIS_KEVIN_1\SQLEXPRESS;Database=Jayhawk;Trusted_Connection=true;"

I do have a user Kevin in SQL and I tried it with the password. I also just tried creating a new user and password and got the same error.

Something else is wrong.

Thanks

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

When you created the "kevin" account in SQL Server Manager, did you tell it to use Windows Authentication or SQL Server Authentication?

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Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Windows Auth

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Next up, on the Server Roles tab, which roles have checkmarks next to them?

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Public & SysAdmin

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

OK, based on your answers, the login should work.

I would go back to SQL Server Manager and create a new SQL account, password, and permissions of dbcreator and public. Change your connection string and remove TrustedConnection and put in the username and password of the account you create.

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Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

That's what I thought too.

I have created a new login and still get the same error. Here's my Conn string

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    var connectionString = @"Server=MAROIS_KEVIN_1\SQLEXPRESS;Database=Test;User Id=FatALbert;Password=AlbertIsFat!;;Encrypt=false;";
    optionsBuilder.UseSqlServer(connectionString, options => options.EnableRetryOnFailure());
}

and the exception

Microsoft.EntityFrameworkCore.Storage.RetryLimitExceededException
  HResult=0x80131500
  Message=The maximum number of retries (6) was exceeded while executing database operations with 'SqlServerRetryingExecutionStrategy'. See the inner exception for the most recent failure.
  Source=Microsoft.EntityFrameworkCore
  StackTrace:
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteImplementation[TState,TResult](Func`3 operation, Func`3 verifySucceeded, TState state)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Program.<Main>$(String[] args) in C:\Projects\SandBox\Learning\EF6Core\Database First\EFCoreDBFirstExample\Program.cs:line 11

  This exception was originally thrown at this call stack:
    [External Code]

Inner Exception 1:
SqlException: Cannot open database "Test" requested by the login. The login failed.
Login failed for user 'FatAlbert'.

I also tried creating the DB 'Test' first in SQL and assigning it to FatAlbert and the same exception.

Again, I have other apps running on my Dev PC that don't use SQL Authentication and they connect just fine. So I has to be something with EF.

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Wait a minute. Did you put the connection string ONLY in the OnConfiguring method?

Asking questions is a skill
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Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Yes. The examples I followed show it there. Isn't that what OnConfiguring does? A one time set up?

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

This works differently from the older Entity Frameworks. The reason you're getting the login failure is because the database does not exist in SQLEXPRESS yet.

You cannot create the database just by running the code you have, as is. You first have to enable migrations in the project, then create your first migration ("InitialCreate"). Once that is done, you can add the following line your program:

C#

using (var db = new ModelContext())
{
    // Update the database to the latest migration
    db.Database.Migrate();

    // Creating a new department and save it to the database
    var newDept = new Departments();
    newDept.DepartmentId = 1;
    newDept.DepartmentName = "Development";

I highly recommend AGAINST doing this! You are far better off managing and applying migrations using the EF command line tools! You can EASILY make a mistake that will destroy a production database just by running your code at the wrong time and with the wrong connection string!

Migrations Overview - EF Core | Microsoft Learn[^]

On top of that, there's a few mistakes in your code in your initial post above. For example, every DbSet should be DbSet<type> ...

C#

public virtual DbSet<Department> Departments { get; set; }
public virtual DbSet<Employee> Employees { get; set; }

...and there are mispellings in your modelBuilder code, like

C#

entity.ToTable("Employees", "public");

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Thanks alot!

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

OK, so I went through the Migrations Oerview and installed the necessary packages. I then ran Add Migration and Update Database. Now I get this

Applying migration '20221127185110_Initial'.
Failed executing DbCommand (2ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
IF SCHEMA_ID(N'public') IS NULL EXEC(N'CREATE SCHEMA [public];');
Microsoft.Data.SqlClient.SqlException (0x80131904): There is already an object named 'public' in the database.
CREATE SCHEMA failed due to previous errors.
   at Microsoft.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at Microsoft.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at Microsoft.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at Microsoft.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean isAsync, Int32 timeout, Boolean asyncWrite)
   at Microsoft.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, Boolean sendToPipe, Int32 timeout, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry, String methodName)
   at Microsoft.Data.SqlClient.SqlCommand.ExecuteNonQuery()
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteNonQuery(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Migrations.MigrationCommand.ExecuteNonQuery(IRelationalConnection connection, IReadOnlyDictionary`2 parameterValues)
   at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationCommandExecutor.ExecuteNonQuery(IEnumerable`1 migrationCommands, IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.UpdateDatabase(String targetMigration, String connectionString, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabaseImpl(String targetMigration, String connectionString, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabase.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
ClientConnectionId:5f3126d9-a1c8-4a81-b0f8-8eba5fd77448
Error Number:2714,State:6,Class:16
There is already an object named 'public' in the database.
CREATE SCHEMA failed due to previous errors.

Set Rant On

This is why I have stayed with Linq-To-SQL. EF is WAAAAAY too complicated. The fact the I need to run console commands is mind-boggling. There's no UI for this? Point & click! And the amount of learning and work to set it up is astounding. And god forbid you make a mistake.

Set Rant Off

Ok, so I'm not even sure what 'public' it thinks is in the DB. It created the DB but not any tables with the exception of MigrationsHistory. So I'm now back where I started - stuck. Any idea what 'public' it's referring to?

Also, do you know of any references that can walk me through setting up & using EF Core. Assume I know nothing. I have this book. I went through the entire first chapter where he sets up the tables, relations, and DBContext, and there's no mention of Migration so far.

Thanks again.

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

modified 27-Nov-22 14:55pm.

Change "public" to "dbo" in your code.

Where did you find this tutorial you're following?

The problem with Linq-To-Sql is that it is a dead product and no longer under development.

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Dave Kreskowiak wrote:
Where did you find this tutorial you're following?

I have the book I mentioned in my other reply, as well as a couple of YouTube vids I followed.

Dave Kreskowiak wrote:
The problem with Linq-To-Sql is that it is a dead product and no longer under development.

Yup. Thats why I'm doing this.

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

OK, I think I have this now.

I did the migration and update, and the DB was created and Department and Employee tables added.

Next, I added a Companies entity, linked it to Departments, and ran

dotnet ef migrations add AddCompanies
dotnet ef database update

and the Db is now up to date.

So I need to run these 2 commands each time I make a change?

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Yes.

You can make a ton of changes and wrap them all in a single migration. Open the migration file and take a look at what's generated.

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

OK, I get it now.

That book I referenced doesn't show any of this, so far. Now I get why nothing was happening when I ran my console app. I was under the impression that creating the DBContext would do all of this

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

In a production environment, you would NEVER hardcode a connection string. This would prevent you from developing against a dev version of the database and testing code and migrations without impacting the production database.

Read the entire section on Migrations, not just the Overview:
Migrations Overview - EF Core | Microsoft Learn[^]

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Ya, I Put it there just for testing.

Thanks for all your help

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Have you checked the file permissions for the database? I suppose that for a Trusted Connection that is not relevant.

Can you open the database using that connection string in SSMS, or VS I suppose?

modified 24-Nov-22 17:59pm.