If I have an EF6 Code First environment in need of a schema change, is it possible to configure it in such a way that I can apply the migration (via Update-Database -Script) before the code gets deployed?
I just ran a simple test with a console app building a DB with migration "Initial", taking a copy of the application at this point. I then modified the schema by adding a new property to my entity and added a "V2" migration and ran Update-Database. When trying to run the "old" code against this migrated DB, I get an InvalidOperationException "The model backing the context has changed since the database was created."
Is the Continuous Delivery type operation where you might want one server running new application code with others running old versions possible with EF code first?
can you modify old code ?
if yes disabling schema checking in old code is an option.
btw: Are you sure the added column is nullable or as a default value ?
to avoid surprises, you can also use a connection string that has read only rights on the schema to avoid data corruption.
Related
I am having an issue where I am getting an error "context has changed since the database was created," but when I look at the migrations history table it is the latest migration. This is a test site, so I updated the database using a sql script I got by running this command "Update-Database -Script -SourceMigration: $InitialDatabase" I can't just delete the whole database and recreate it. Has anyone run into a similar issue like this? Currently, I am using EF 6.1.3.
Note: I used code-first for this, so it was not an existing database I am adding to.
The issue was that a new directory had been created for the site due to the domain name being changed. I knew the domain name had changed, but didn't realize the physical directory had changes. It was such a slight change I missed it when I was checking the application paths (an s was removed). So the problem was caused by pebkac (problem exists between keyboard and chair).
Try to set your Initializer to null in the constructor of your DbContext class.
Like this:
Database.SetInitializer<YourDbContext>(null);
ScottGu's Blog explains why this happens :
http://weblogs.asp.net/scottgu/using-ef-code-first-with-an-existing-database
Have you tried using this command instead of executing a script?
Update-Database -Force
If you have enabled auto migrations, this should pick up your code-first changes and deploy them. The force will allow columns which have data to be dropped etc.
I have two folders for my migrations (AuthContext and UserProfileContext), each has their own migration and some custom sql to run afterwards for data migrations and whatnot.
This works fine when using package manager console. I
Restore from production
Run Update-Database -ConfigurationTypeName Migrations.Auth.Configuration
Run Update-Database -ConfigurationTypeName Migrations.UserProfile.Configuration
Then everything is very happy in the new database, migrations executed data shuffled where it needs to.
I tried to test out the migrations on publish piece by:
Restore production on dev database
Single connection string (all contexts use the same) pointed to dev database
Publish to azure web site
Checked the box for Apply Code First Migrations
Selected that single connection string
Okay it published fine; however, when I went to look at the database, nothing happened! It did not create the necessary tables, columns, or data moves.
TLDR; Code first migrations are not running after publish to Azure
Update 1
I've tried any combination of the below: only one single connection string so I'm guessing that's not the issue, and execute migrations is checked.
On publish the api runs but no database changes are made. I thought perhaps I needed to hit it first but I just get random errors when I try to use the api (which now of course relies on the new database setup), and the database is still not changed.
I've seen a couple references out there about needing to add something to my Startup class but I'm not sure how to proceed.
Update 2
I solved one issue by added "Persist Security Info=True" to my connection string. Now it actually connects to the database and calls my API; however, no migrations are running.
I attached debugger to Azure dev environment and stepped through... on my first database call it steps into the Configuration class for the Migration in question, then barfs and I can't track down the error.
public Configuration()
{
AutomaticMigrationsEnabled = false;
MigrationsDirectory = #"Migrations\Auth";
ContextKey = "AuthContext";
}
Update 3
Okay, dug down and the first time it hits the database we're erroring. Yes this makes sense since the model has changed, but I have migrations in place, enabled, and checked! Again, it works fine when running "Update-Database" from package manager console, but not when using Execute Code First Migrations during publish to Azure
The model backing the 'AuthContext' context has changed since the
database was created. Consider using Code First Migrations to update
the database (http://go.microsoft.com/fwlink/?LinkId=238269).
Update 4
Okay I found the root issue here. VS is setting up the additional web.config attrib for databaseInitializer on only one of my database contexts, the one not mentioned is in fact hit first from my app.
So now I have to figure out how to get it to include multiple contexts, or, combine all of my stuff into a single context.
The answer to this post is not very detailed.
This article explains what I had to do to fix a similar problem to this:
https://blogs.msdn.microsoft.com/webdev/2014/04/08/ef-code-first-migrations-deployment-to-an-azure-cloud-service/
I'll roughly describe the steps I had to take below:
Step 1
Add your connection strings to your dbContexts, in my situation, they were both the same.
Step 2
Add this to your web.config
<appSettings>
<add key="MigrateDatabaseToLatestVersion" value="true"/>
</appSettings>
Step 3
And add this to the bottom of your global.asax.cs / Startup.cs(OWIN startup)
var configuration = new Migrations.Configuration();
var migrator = new DbMigrator(configuration);
migrator.Update();
Solved! To summarize the solution for posterity:
Enable Code First Migrations only enables them for one base connection string per checkbox checked, regardless of how many contexts have migrations against that base connection string. So in my case I broke out the two in question into two different connection strings.
Then I was hitting other errors and identified that if you're changing the base connection string to the model backing asp identity you need to include (one time publish) the additional flag base("AuthContext" , throwIfV1Schema: false)
For anyone who has this issue and may have overlooked the following: be sure to check that you have correctly set the connection string in your Web.config file and/or Application settings on Azure. This includes DefaultConnection and DefaultConnection_DatabasePublish.
In our case the former was correct but the latter contained the wrong database instance because it had been carried over from an App Service clone operation. Therefore the wrong database was being migrated.
I have an application developed in scala play2.0,
it worked successfully in local, but if failed when deployed to heroku.
the reason of the fail is that locally i was using a H2 database,
and using postgresql in heroku, i have to change one of the data types from "clob" to "text".
the problem now is that the database in heroku is in a "inconsistent state", according to the play20 documentation.
in DEV mode (locally), you can just click on the "Mark it as resolved" when the html appears.
how to "mark it ask resolved" in the heroku PROD environtment?
http://www.playframework.com/documentation/2.1.1/Evolutions
ps: note, because it was a new application, i just deleted the database and re-started.
however, here i am asking what is the proper way to handle evolutions in the PROD env.
that is, the "Mark it as resolved" issue for PROD is not explained here: http://www.playframework.com/documentation/2.1.1/Evolutions
Although I couldn't find a way to do it via the play command, you can do it by editing the database directly.
Imagine you're trying to go from 5.sql to 6.sql. Here's what you do:
Figure out and fix the problem(s) that caused the database to enter an inconsistent state (i.e. manually apply your !Ups and fix all the problems with them).
Manually apply your !Downs so that the database is in the state it was after 5.sql was applied.
Go into your database, find the table called play_evolutions, and look at the row with id 6. It should saying something like applying ups in the state column and have the error message in the last_problem column.
Delete the row with id 6. This will make Play think you are in the state you were with 5.sql.
Now you should be able to run play -DapplyEvolutions.default=true start to evolve to 6.sql.
Inconsistent state just means that the evolutions could not be applied and thus, the application is blocked. Update your evolution scripts and re-deploy.
I would like to introduce Code First Migrations to my project, but I am unsure of how to handle deploying this to my client for testing. Until now, things have been quite simple, and I have just used a CreateDatabaseIfNotExists initializer. Now, I have two scenarios:
He deletes his existing, before-migrations, database, and uses an initializer to create a new, with-migrations, database, and we use migrations from here on to upgrade his database. Can I use the MigrateDatabaseToLatestVersion initializer to create the DB if missing as well?
I just deploy my code and let it perform migrations. I'm not quite sure if anything but using a MigrateDatabaseToLatestVersion is required here. Will this upgrade a pre-migrations database to one suitable for migrations?
This is what I do when automatic migration is required; I hope this helps you find a solution:
Database.SetInitializer(
new MigrateDatabaseToLatestVersion<ContextFileName, PathToMigrationsConfig>()
);
Database.Initialize(false);
In the configuration file for the migrations, I set the following in the constructor
AutomaticMigrationsEnabled = true;
AutomaticMigrationDataLossAllowed = false;
In the configuration file you should have an override of the seed method, if not you can add it and fill in your seed data.
What the above will do is create/upgrade the database to the latest as long as no data loss occurs. This should allow you hand off the code to the client.
On a side note, for a production system I will usually argue the point of not doing this. This had many disadvantages. For databases I do not have control over I have yet to find a client that has refused the generated script file.
You can get this by using the following command after you add a migration through the Package Manager Console:
Update-database –script -verbose
I cannot get the Entity Framework to work against SQL Azure. Is this just me or is it not intended to be compatible? (I have tried the original release of EF with VS2008 as well as the more recent VS2010 Beta 2 version)
To check this I created the simplest scenario possible. Add a single table to a local SQL Server 2008 instance. The table has two columns, a primary key of type integer and a string column. I add a single row to the table with values of (1, foobar). I then added exactly the same setup to my SQL Azure database.
Created a console application and generated an EF model from the local database. Run the application and all is good, the single row can be returned from a trivial query. Update the connection string to connect to the SQL Azure and now it fails. It connects to the SQL Azure database without problems but the query fails on processing the result.
I tracked the initial problem down using the exception information. The conceptual model had the attribute Schema="dbo" set for the entity set of my single defined entity. I removed this attribute and now it fails with another error...
"Invalid object name 'testModelStoreContainer.Test'."
Where 'Test' is of course the name of the entity I have defined and so it looks like it's trying to create the entity from the returned result. But for some unknown reason cannot work out this trivial scenario.
So either I am making a really fundamental error or SQL Azure is not compatible with the EF? And that seems just crazy to me. I want to use the EF in my WebRole and then RIA Services to the Silverlight client end.
While I haven't done this myself I'm pretty sure that members on the EF team have, as has Kevin Hoffman.
So it is probably just that you went astray with one step in your porting process.
It sounds like you tried to update the EDMX (XML) by hand, from one that works against a local database.
If you do this most of the changes will be required in the StorageModel element in the EDMX (aka SSDL). But it sounds like you've been making changes in the ConceptualModel (aka CSDL) element.
My guess is you simply need to replace all references to the dbo schema in the SSDL with whatever schema is the SQL Azure schema.
Hope this helps
Alex
To answer the main question - Yes, at least the Entity Framework v4 can be used with SQL Azure - I haven't honestly tried with the initial version (from the .Net Framework 3.5. SP 1).
A little while back I did a complete project and blogged about the experience: http://www.sanderstechnology.com/?p=9961 Hopefully this might help a little bit!
Microsoft's Windows Azure documentation contains How to: Connect to Windows Azure SQL Database Using the ADO.NET Entity Framework.
After creating your model, these instructions describe how to use SQL Azure with the Entity Framework:
Migrate the School database to SQL Database by following the instructions in How to: Migrate a Database by Using the Generate Scripts Wizard (Windows Azure SQL Database).
In the SchoolEFApplication project, open the App.Config file. Change the connection string so that it connects to your SQL Database.
<connectionStrings>
<add name="SchoolEntities"
connectionString="metadata=res://*/SchoolDataModel.csdl|res://*/SchoolDataModel.ssdl|res://*/SchoolDataModel.msl;provider=System.Data.SqlClient;provider connection string="Data Source=<provideServerName>.database.windows.net;Initial Catalog=School;Integrated Security=False;User ID=<provideUserID>;Password=<providePassword>;MultipleActiveResultSets=True;Encrypt=True;TrustServerCertificate=False""
providerName="System.Data.EntityClient"/>
</connectionStrings>
Press F5 to run the application against your SQL Database.