I needed to add a new NVARCHAR column to a table in my DB. So I added the column, and then fired up Visual Studio to update the EDMX-file for the Entity Framework.
I ran update model from database on everything, which only resulted in "data reader is incompatible"-errors. So I renamed the whole table in the DB, updated EDMX from database, renamed the table back to the original name, ran update again, and then created new function imports for all affected stored procedures. But I still get the same error:
The data reader is incompatible with
the specified '[Model].[Entity]'. A
member of the type,
'[Column]', does not have a
corresponding column in the data
reader with the same name.
I've looked around a bit, and this seems to be a common error if the column name is different in the database and framework. This is however not the case, they have the same name.
I can access the column in the code via [Entity].Context.[Column], so I don't quite see what the data reader is complaining about.
I've run out of ideas, so any help welcome.
Updating the model replaces the store schema, but not the client schema or the mapping. To start with "a clean slate", back up your current EDMX, then open it as XML. Remove all references to the table, then close and open in the graphical error. Build. If you have any errors (perhaps broken links to the deleted table), fix them. Then update model to re-add the table.
Just had the same issues as above. Tried removing the entity from the edmx, tried removing and re-adding the function import, and finally rebuilt using a complex type in the function import and that didn't work either.
I realize this error can occur for really any scenario where there is a mismatch but we found the issue was in the stored proc we used for the function import. The stored proc was using specific select columnname, columnname etc and the new column we added to the table was not in that list. To test, we used the *, updated the EDMX and it resolved our issue.
Turns out the EDMX was fine, but the designer has, for some odd reason, stopped update Designer.cs in my project.
Had to go in and manually edit it.
For me it was an issue where I altered an entity (vertical entity splitting), but one of my stored procedures wasn't pulling data for that new field. I added it (in the SP) and now everything runs fine.
Unless it's simply adding a new item, This throws an error just about every time I try to "Update model from database" ...
The solution is luckily very simple -
1) Open Web.config, find <connectionStrings> node
2) Delete the DBNameEntities <connectionStrings>
- this way you do not have to modify any references to your emdx model
2) Delete the ADO.NET Entity Data Model (.emdx)
3) Re-add the ADO.NET Entity Data Model (.emdx) with the same name.
Its faster and bulletproof. (so far!?)
If you Re-Add the DataModel you will lose all DataBindings - especially bindings of controls on your form (like DbGrid). I have fixed this issue manually editing the DataModel.edmx file in external Editor.
Related
I'm using EF 6.0.0 and .Net 4.5.
I face a very confusing problem. Me and one of my colleagues are working on the domain model section of our project on two different clients. The problem is:
1- Me and my colleagues start with the absolutely identical project and we are completely synced with the source control.
2- When I change the model for example add a property then Add-Migration FromA then Update-Database it works great. The generated code file contains just one command that is to add the column.
3- Meanwhile, after the db is updated and just before I check in something to source control, my colleague adds another property and then Add-Migration FromA then Update-Database. And guess what? This generated code file has a command to drop the column I newly added!!!
I added another column using native Sql, and fortunately the column is not going to be deleted.
I deleted the __MigrationHistory table and the remove column didn't get generated.
I turned off initializer Database.SetInitializer<MyContext>(null), no success.
So, my guess is that EF Migrations compares current model with the last one stored in __MigrationHistory table not the last local snapshot stored in .resx file. Am I right? Any way to solve the problem?
I am using Linq to SQL approach to do manipulation with the database tables. I am stuck with the one problem, whenever I am adding a new column to my existing tables then I have to delete existing .dbml file of the table from the Solution and then have to add again to get the access of last added columns.
I tried the approach by re-building Project and the Solution as well but still, It doesn't work and pushes me to do the above less-sensible steps.
Could you help me out to get rid of this issue? or It is the only way I have to get the changes by adding .dbml file again.
I am using Entity Framework code first for the first time in a production environment. Everything went fine until we got the DB up and had put some of the data in it and then to get some of the data we were importing from another location we had to change field lengths. So we made some of the fields nvarchar(99) instead of nvarchar(50).
That went fine and the application still worked but I knew I needed to change the data annotation or it would blow up later when it loaded and tried to save a too long field. When I did that the app blew up even though the model and the db are now matching. So I thought that it was the hash in the metadata table so I thought I'd be clever and make a new DB and take the hash from there and copy it. That did not work and in fact now I cannot get my app to connect to the test db that we have data loaded in at all.
I do not want to drop and recreate this database. I want entity framework to realize that the model and the schema do in fact match. Is there any way for me to do this? Also why did copying the metadata from a DB that entity framework created with this model not work?
Entity Framework Code First creates a EdmMetadata table and saves a hash of your Model classes in it. When you change something in the Model, the hash of the new Model classes doesn't match what's in the EdmMetadata table anymore, and the app should "blow up" at runtime. What you need to do to keep using the same database without dropping it, is to delete the EdmMetadata table. This way EF will not do that check and will try to proceed with the access to the DB.
Check this video tutorial (skip to 8:10 of the "When Classes Change" section).
Sorry I fixed this. Removing the metadata worked. But turns out I had updated to a more recent version of EntityFramework accidentally while trying to fix my problem and this more recent version expected different naming conventions for the Database. In any case recreating the many-to-many group person table with a script from a DB created by Entity Framework and deleting the metadata fixed the problem.
I have been updating my Entity Framework by simply right clicking and clicking on "update model from database". I usually go under the "Add" tab and then click the tables and click finish. I also use "refresh" sometimes as well. What are the differences between these? and also when I do refresh or add sometimes the entity comes out wrong or keeps some of the old information in cache, how can I just get the entity to match my database and clean out any of the old cached things.
Yes, you are right. The designer is a bit buggy and doesn't handle certain schema changes particularly well. As a rule, when I add a table to the database, I run Update model from database and select the table in the Add tab. Works fine. If I add a field to an existing table, I do Update model and Refresh. Works well too.
But if I add one field and remove another, or rename an existing field (as far as I remember), EF does not handle this correctly (added a new field but failed to remove the old one, and since the old one remained unmapped, the model validation failed). So in those more complex cases I usually delete the entity and then do Update model from database and Add it again.
The downside is that if you did make some changes (e.g. renamed some fields or navigational properties of the entity), you'll have to do those changes again.
It doesn't clean out old items. You have to delete those yourself. On the positive side, Visual studio will give you an error when you compile, stating that a coloumn or two isn't mapped. The entity framework tool is more of a code generator. It generates classes based on the structure of your database, as opposed to being tied to the database for is't structure information.
Designer is not buggy and the reason why it doesn't handle some changes is because CSDL and some MSL modifications made by user are not overwritten. CSDL is the diagram you see in designer and MSL is the mapping of your entities and associations.
Believe me this is a big step forward comparing to Linq-to-sql where no update existed and you always had to delete everything including your changes when you wanted to refresh your model. If you made a lot of changes you can always delete your entity in EF designer as well. EF designer offers a choice to update or recreate (by deleting the old one).
I've got a pretty large DB hooked up to my Entity Framework. I've got one particular set of tables where a common key (fk) was deleted from the design. When I "update the model from the database", I get a series of errors about this now-missing key.
Why doesn't the update process accurately detect that this key was removed? Also, if I manually remove the property from the model, I just end up with other errors. I also tried to simply delete the table and re-add it, but now the table doesn't show up in the "Add" section of the update wizard.
So, short of deleting the entire thing and starting over, is there any way to recover gracefully? Has the EF team released any newer versions of this wizard that has some of these issues fixed in it already?
Entity Framework does get confused from time to time. What you need to do is delete the Entity Table from the model, then rename the table in SQL Server to TableName_Temp, refresh the model, now the Entity Table should be OK, so delete the entity table again rename it back to the original name and refresh the model once more. This time everything should be fine.
I know this is a messed up procedure but this is the only way I found to fix this issue without blowing away the entire edmx and starting from scratch. Currently at my organization we have a policy not to make changes to the EDMX unless absolutely necessary so that we can delete and recreate when ever needed without any problems.
Hope this helps!