I created the databases first, then used the wizards in Entity Framework 5 to create the models from the Database first. Over time, through development, I made changes to the models and let EF recreate them by deleting my database and then starting the project up and they magically appeared again with the changes I made to the columns . It worked great on SQL Express 2014. But Godaddy doesnt let EF do that, AND I have databases with names like "Hazards.Models.CompanyDataContext" that EF made and didnt ask me what I wanted to name them. How do I change the code so it will let me rename the database it uses, and if possible, incorporate it into the aspnetdb that mvc uses as an additional table (there already is simplemembership etc. in there.)?
Seeing as you used EF database first, rather than deleting your database and letting EF recreate it, have you thought about doing it the other way round?
You could use something like management studio express to rename your database tables/columns however you see fit. Then in Visual Studio, open your .edmx file, right-click the background and select 'update model from database'. This way you can add new tables to the model or update the models of existing tables from the database. Better still, you can take care of it all outside of godaddy.
Note: I found that when updating the EF model, just updating existing tables gives odd results sometimes. It's much more reliable when you delete tables from your .edmx first, then right-click and select 'update model from database', and add the tables back to your model.
I have got into a bad state with my ASP.Net MVC 5 project, using Code-First Entity Framework. I don't care about losing data, I just want to be able to start fresh, recreate the database and start using Code-First migrations.
Currently I am in a state where every attempt to Update-Database results in an exception being thrown or getting an error message. Also the website can't access the database correctly. How can I wipe all migrations, re-create the database and start from scratch without having to create a new project? In other words, I want to keep my code but drop the database.
Later I will also want to get the deployment database (SQL Server on Azure) in sync. Again, I don't mind dropping all the data - I just want to get it working.
Please provide any how-to steps to get back to a clean state. Much appreciated.
Follow below steps:
1) First go to Server Explorer in Visual Studio, check if the ".mdf" Data Connections for this project are connected, if so, right click and delete.
2 )Go to Solution Explorer, click show All Files icon.
3) Go to App_Data, right click and delete all ".mdf" files for this project.
4) Delete Migrations folder by right click and delete.
5) Go to SQL Server Management Studio, make sure the DB for this project is not there, otherwise delete it.
6) Go to Package Manager Console in Visual Studio and type:
Enable-Migrations -Force
Add-Migration init
Update-Database
7) Run your application
Note: In step 6 part 3, if you get an error "Cannot attach the file...", it is possibly because you didn't delete the database files completely in SQL Server.
I would like to add that Lin's answer is correct.
If you improperly delete the MDF you will have to fix it. To fix the screwed up connections in the project to the MDF. Short answer; recreate and delete it properly.
Create a new MDF and name it the same as the old MDF, put it in the same folder location. You can create a new project and create a new mdf. The mdf does not have to match your old tables, because were going to delete it. So create or copy an old one to the correct folder.
Open it in server explorer [double click the mdf from solution explorer]
Delete it in server explorer
Delete it from solution explorer
run update-database -force [Use force if necessary]
Done, enjoy your new db
UPDATE 11/12/14 - I use this all the time when I make a breaking db change.
I found this is a great way to roll back your migrations to the original db:
Puts the db back to original
Run the normal migration to put it back to current
Update-Database -TargetMigration:0 -force [This will destroy all tables and all data.]
Update-Database -force [use force if necessary]
This worked for me:
Delete database from SQL Server Object Explorer in Visual Studio.
Right-click and select delete.
Delete mdf and ldf files from file system - if they are still there.
Rebuild Solution.
Start Application - database will be re-created.
While this question is premised by not caring about the data, sometimes maintenance of the data is essential.
If so, I wrote a list of steps on how to recover from Entity Framework nightmare when the database already has tables with the same name here: How to recover from Entity Framework nightmare - database already has tables with the same name
Apparently... a moderator saw fit to delete my post so I'll paste it here:
How to recover from Entity Framework nightmare - database already has tables with the same name
Description: If you're like us when your team is new to EF, you'll end up in a state where you either can't create a new local database or you can't apply updates to your production database. You want to get back to a clean EF environment and then stick to basics, but you can't. If you get it working for production, you can't create a local db, and if you get it working for local, your production server gets out of sync. And finally, you don't want to delete any production server data.
Symptom: Can't run Update-Database because it's trying to run the creation script and the database already has tables with the same name.
Error Message: System.Data.SqlClient.SqlException (0x80131904): There
is already an object named '' in the database.
Problem Background: EF understands where the current database is at compared to where the code is at based on a table in the database called dbo.__MigrationHistory. When it looks at the Migration Scripts, it tries to reconsile where it was last at with the scripts. If it can't, it just tries to apply them in order. This means, it goes back to the initial creation script and if you look at the very first part in the UP command, it'll be the CreeateTable for the table that the error was occurring on.
To understand this in more detail, I'd recommend watching both videos referenced here:
https://msdn.microsoft.com/en-us/library/dn481501(v=vs.113).aspx
Solution: What we need to do is to trick EF into thinking that the current database is up to date while not applying these CreateTable commands. At the same time, we still want those commands to exist so we can create new local databases.
Step 1: Production DB clean
First, make a backup of your production db. In SSMS, Right-Click on the database, Select "Tasks > Export Data-tier application..." and follow the prompts.
Open your production database and delete/drop the dbo.__MigrationHistory table.
Step 2: Local environment clean
Open your migrations folder and delete it. I'm assuming you can get this all back from git if necessary.
Step 3: Recreate Initial
In the Package Manager, run "Enable-Migrations" (EF will prompt you to use -ContextTypeName if you have multiple contexts).
Run "Add-Migration Initial -verbose". This will Create the initial script to create the database from scratch based on the current code.
If you had any seed operations in the previous Configuration.cs, then copy that across.
Step 4: Trick EF
At this point, if we ran Update-Database, we'd be getting the original error. So, we need to trick EF into thinking that it's up to date, without running these commands. So, go into the Up method in the Initial migration you just created and comment it all out.
Step 5: Update-Database
With no code to execute on the Up process, EF will create the dbo.__MigrationHistory table with the correct entry to say that it ran this script correctly. Go and check it out if you like.
Now, uncomment that code and save.
You can run Update-Database again if you want to check that EF thinks its up to date. It won't run the Up step with all of the CreateTable commands because it thinks it's already done this.
Step 6: Confirm EF is ACTUALLY up to date
If you had code that hadn't yet had migrations applied to it, this is what I did...
Run "Add-Migration MissingMigrations"
This will create practically an empty script. Because the code was there already, there was actually the correct commands to create these tables in the initial migration script, so I just cut the CreateTable and equivalent drop commands into the Up and Down methods.
Now, run Update-Database again and watch it execute your new migration script, creating the appropriate tables in the database.
Step 7: Re-confirm and commit.
Build, test, run. Ensure that everything is running then commit the changes.
Step 8: Let the rest of your team know how to proceed.
When the next person updates, EF won't know what hit it given that the scripts it had run before don't exist. But, assuming that local databases can be blown away and re-created, this is all good. They will need to drop their local database and add create it from EF again. If they had local changes and pending migrations, I'd recommend they create their DB again on master, switch to their feature branch and re-create those migration scripts from scratch.
Just want to add to the excellent answer of #Lin:
5) B.
If you don't have SQL Management Studio, go to "SQL Server Object Explorer".
If you cannot see your project db in the localdb "SQL Server Object Explorer", then click on "Add SQL server" button to add it to the list manually. Then you can delete the db from the list.
A possible very simple fix that worked for me. After deleting any database references and connections you find in server/serverobject explorer, right click the App_Data folder (didn't show any objects within the application for me) and select open. Once open put all the database/etc. files in a backup folder or if you have the guts just delete them. Run your application and it should recreate everything from scratch.
My solution is best suited for :
- deleted your mdf file
- want to re-create your db.
In order to recreate your database you need add the connection using Visual Studio.
Step 1 : Go to Server Explorer add new connection( or look for a add db icon).
Step 2 : Change Datasource to Microsoft SQL Server Database File.
Step 3 : add any database name you desire in the Database file name field.(preferably the same name you have in the web.config AttachDbFilename attribute)
Step 4 : click browse and navigate to where you will like it to be located.
Step 5 : in the package manager console run command update-database
Webmatrix is hanged while I query cmsDocument table in SQL CE database, I can query other tables but this gives me error, and it says that "Unable to cast object of type 'System.DBNull' to type 'System.String'.". I also found out that cmsDocumentType table query is also a problem. How will I fix this?
And another issue is the content, document type and template I created previously are gone and just the old content is available. I renamed the main node in umbraco 6.16 site and added new nodes , saved and published. Now all new contents are lost.
I think these two issues are linked. I appreciate any suggestion.
I just found out that after there is any change in the content, the whole website should be refreshed in the WebMatrix. Otherwise, all the changes will be disappeared when the project is closed.
I have an existing iPad application to which I've just added core data versioning. I've been through the documentation and followed the steps detailed. Now after choosing my new model as the current versioned model and trying to run it on my dev device from xCode I get the following error:
2012-03-28 07:35:42.137 DocsOnTap[2603:707] CoreData: error: (1) I/O error for database at /var/mobile/Applications/06EECF01-3598-4513-8A3A-BE4FD49EEBF6/Documents/.DocsOnTap.sqlite.migrationdestination_41b5a6b5c6e848c462a8480cd24caef3. SQLite error code:1, 'table Z_2TAG already exists'
The only change that I made to my model was to add in a single new entity. I have a table named Tag in my model - that appears to be what the error is referring to.
If I revert my current versioned model back to the previous model version then I can run my app on my dev device from Xcode without error.
I have read that there can be problems trying to use core data migration on dev devices. However I just want to test the process to be sure that when we update our app in the Appstore the migration works as expected for our customers.
In my case the same error appeared due to Renaming ID which was set in the Data Model inspector for the Entity. After I removed the Renaming ID the problem'd gone.
Well this was an obscure error. The entity that I was adding was named AppKeys - this must be the name of an entity used internally by core data or SQL Lite. I went back to scratch and found that I could add and migrate other attributes and entities without any problems. However if I tried once again to add my entity named AppKeys then I got the same error saying that 'table Z_2TAG already exists'. So the resolution to my problem is to choose another entity name. It is a pity that this is not documented somewhere obvious - or that the error was not more helpful. Anyway hopefully this might just help someone else one day.
I'm working on updating an old system, and we're introducing Entity Framework for some new functionality. The system is, however, too large to do the migration in one step, so I would like to do some testing in another database before updating the db schema.
I have created an empty model, included a couple of tables from the database, and added a couple of new entities from scratch, along with relationships between these entities and the old tables. Now I want to create a new database schema in another database with my desing model, but I can't figure out how to switch so that clicking "Update database from model..." won't work with the old database, but the with the new one.
Is there a straight-forward way to do this?
In short, the connection settings are in your config file or a Data Connection. Entity Framework Connections and Models provides official documentation.
If your connection settings are in your config file, i.e. Web.config / App.config, you can change them there (additional documentation available in Entity Framework Config File Settings). If you used EF Designer to create your model, the option to save settings in the config file was in the Choose Your Data Connection Dialog Box (Generate Database Wizard).
If your connection settings aren't in a config file, they live in the Data Connection in the Server Explorer in Visual Studio: View > Server Explorer; expand Data Connections, right-click on the connection and choose Modify Connection.