I am trying to do some tests using EF4 + CTP5 with code first development by writing POCO classes and have faced the following problems
Connecting to existing database throws me the exception:
Model compatibility cannot be checked because the database does not contain model metadata
While I can create a new database from code by giving a new file name in a connection string, not able to open the file (database) using the Management Studio after running few tests against, the Management studio doesn't allow to add the file when trying to attach the database with no specific error detail provided.
For #1, did you try adding the following to your global.asax?
Database.SetInitializer<CustomContextNameHere>(null);
where "CustomContextNameHere" is your context object.
As far as #2 goes, I am assuming you mean the default ASPNETDB.MDF file. Have you tried opening the file with the Server Explorer in VS? It may open right up if you double-click on it in the solution.
Related
I am running a migration script using package manager console after setting dependencies in corresponding files in dot net core based project and i am receiving below error after running the below migration command in package manager console ,
Add-Migration "InitialCreate"
Error received :
Unable to create an object of type 'PaymentDetailContext'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728
I have gone through different ways to troubleshoot this issue inorder to create a migration file
I am logging using windows authentication method and kindly help me to resolve this issue in visual studio 2022
Entity framework Dot Net Core Error In Adding Migrations
I have tried to check all the corresponding files whether any spelling mistakes in connection string file , added corresponding packages using browse option and installed
I am expecting this error to be resolved (below one ) after executing the script
Add-Migration "InitialCreate"
Unable to create an object of type 'PaymentDetailContext'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728
and thereby generating the migration script inside web api project
I recently added a Visual Studio 2012 Desktop Project to a Visual Studio 2012 Solution that contains several Web Apps Projects and 1 Class LIbrary Project. The Class Library handles the EF 5 Code First Database Model that is shared for all the Web App in the solution.
The class LIbrary Project is the only one I used to update the database. The rest of the web projects are just consumers of that DLL library.
Now I'm trying to add a Visual Studio 2012 Desktop Application project to the same solution. The goal is for the Desktop App to use the same Class LIbrary DLL to interact with the database.
I added the Desktop Project to the solution and created the reference to the class library DLL. After I made changes on it to access the database through this DLL, like:
ContextDB db = new ContextDB();
ClassLib.Models.Gallery gallery = (from g in db.Galleries where g.GalleryId == galleryId select g).SingleOrDefault();
After the desktop Project is built I ran it and the first error that shows is:
The model backing the 'ContextDB' context has changed since the database was created. Consider using Code First Migrations to update the database
Then I tried to solve using this line of code just before the ContextDB definition:
Database.SetInitializer<ContextDB>(null);
ContextDB db = new ContextDB();
That solved that problem but now it is showing another error related with INVALID COLUMNS in almost all the columns on the table, the error is:
Invalid column name 'EventId'.
Invalid column name 'WebsiteId'.
Invalid column name 'Slug'.....
and so on for all the columns on the table..
There's nothing wrong with the database and other projects in the solution are using the Class Library without any problem.
I'm not sure what to do now.
I have a Solution with three projects. One are the models, another is the repository and context configuration and the last one is a Web application.
The things is that when i configure the Entity Framework in the Repository Project and add the migrations, and i try to execute update-migration nuget console this throw me and error.
I need the database in a mdf file so the app.config look this way:
The error when i try to update-migration is:
The physical file name "/ExampleDB.mdf" may be incorrect
By the error i understand that |DataDirectory| is not working and i can't set it with
AppDomain.CurrentDomain.SetData("DataDirectory", Directory.GetCurrentDirectory()); because this project is a class library.
Thanks a lot
I'm experimenting with EntityFramework 4.3 using CodeFirst. I have worked with EF 4.0 ModelFirst and DatabaseFirst for about two years now and want to integrate CodeFirst into an exiting CRM Database project. (...but tried it without an existing Database!)
I am using VS 2010, VB.Net ans SQLEXPRESS Server 2008 for developing.
So I started with a NEW project using the msdn-Examples: "EF 4.2 Code First Walkthrough"
( http://blogs.msdn.com/b/adonet/archive/2011/09/28/ef-4-2-code-first-walkthrough.aspx )
and a VB.NET adaption from "Productivity Improvements for the Entity Framework"
( http://blogs.msdn.com/b/vbteam/archive/2010/06/21/productivity-improvements-for-the-entity-framework.aspx )
I quote: "That is 100% of the code you would write to get this program running. No separate model definition, XML metadata, config file or anything else is required. "
Well, that seems not to be true for my system.
I installed EntityFramework 4.3 with NuGet Packet Manager and the Reference is correctly there.
I first tried it without App.Config - adaption. I got the InvalidOperationException ... not mapped:
"The type 'CodeFirstSample.MyDataAccessDemo.Program + Product' was not
mapped."
I added a database connectionString to the app.config for my SQL Server-connection, created a database "Products" and tried again.
Same error...
What did I do wrong?
I googled a lot but couldn't find any hints.
I suppose you have some problem with Database initialization and Connection string .
It's necessary you define your database initialization strategy at starting point of your project , One example could be :
Database.SetInitializer(
new DropCreateDatabaseIfModelChanges<YourContext>());
I do recommend try some of Julie Lerman's Source code example , I assure you it 100% work with sql server 2008 express and visual studio 2008 without touching a line of code , Just hit F5 .
You have to bring Blog and Post classes out of Main class.
Please look at this post:
http://social.msdn.microsoft.com/Forums/en-US/adodotnetentityframework/thread/84dd6851-9ee5-48a2-950b-de90cdb30cb0/
It looks like CodeFirst stops doing its homework when it doesn't have full control of the database (I suppose).
The scenario is a web site hosted on Arvixe.com (or I suppose any other shared hosting server), where I have to create databases only from their control panel (and NOT with Sql Server Management Studio, just to say...).
Once created an empty database, I register a connection in the web site, and I use it to generate database from poco objects like in:
add-migration m1 -targetdatabase myconnection
This generates correctly my FIRST migration, that I can apply without problems with
update-database -targetdatabase myconnection
The first concern, not too important, is that since the database is existing, it will NOT issue the Seed command, so I have to insert my first records by hand, but this is not a great problem.
Then I change my poco objects, and I need to update the database, but when I issue ANOTHER
add-migration m2 -targetdatabase myconnection
it gives the error:
System.Data.Entity.Migrations.MigrationsPendingException: Unable to generate an explicit migration because the following explicit migrations are pending: [201111081426466_m1]. Apply the pending explicit migrations before attempting to generate a new explicit migration.
This is really strange, since if I look at the database, I can see even the table __MigrationHistory, but then it looks like it cannot recognize it...
Anyone with the same problem, or some good tip to where investigate?
Thanks in advance,
Andrea Bioli
I had this problem. I was able to resolve it by providing a connectionString and a connectionProviderName parameter to both the Update-Database and the Add-Migration commands.
If you have many projects in your solution with multiple config files, Package Manager seems to be confused. In my case, I had one project selected as the default project for Package Manager Console, but it was pulling the connection string from the Visual Studio solution default start-up project instead.