So we're using the new SSDT Microsoft released, pretty cool stuff. We are keeping a database project under version control with all the schemas, and an offline database for development and we can later deploy on SQL Azure database. We;re using EF in development, so my question is where would the edmx fit in, should we update the edmx file from the offline database or from the online SQL Azure directly, whats the best practice on this?
I would say that in your case "the production database is the truth", so I would update from SQL Azure. There's no right answer tho really.
Incidentally, in the early betas of SSDT it was possible to have a reference from an EDMX to a SSDT project thus your source code became the truth (which, in my opinion, is preferable) and the EDMX knew it was always working against "the truth". Unfortunately they ditched this feature and there are no signs of it returning.
For the EF to work correctly the EDMX file has to be in-synch with the database you are connecting to. It's hard to answer your question without knowing the development process you follow but I would imagine you use Sql Azure in production and develop against an on-premises database. Therefore one copy of the Edmx file will be used on production server. In the development environment you have a "living" copy of the edmx file that is changed as needed when the local database changes. When you get to the point you when you are ready to ship you deploy your app (include the edmx file) to a production environment that uses Sql Azure.
If, in your development environment, you update the edmx file from the SQL Azure then stuff will break or will not work correctly if the schema of the database in Azure is different from schema of your local database.
Related
I have 2 databases, development and production.
I added a new entity, added a migration then updated the development database.
It worked, development database has the new table.
I switched the database in my configuration to the production database.
I used Update-Database command from Package Manager Console but nothing happened.
My production database still doesn't have the new table.
What now?
What is the valid workflow for such scenario?
BTW, both databases already contain structure and data. The production database contains more recent data, the development database is one migration ahead.
UPDATE: I tried to revert the last migration on development database, it worked. Then I tried to apply it again on production. Didn't work. It seems like it refuses to apply the same migration again.
OK, I figured it out.
I assumed when I change the runtime profile for production the file appsettings.Production.json will be loaded on migration.
It didn't happen. The migration used appsettings.Development.json instead.
I changed the connection string in my appsettings.Development.json file to the production database and it worked.
It's weird, when I debug the web application it respects the settings. It either uses the development or production settings, as selected in Visual Studio. Migrations just use the development file.
If there's a cleaner way (IDK, tell the Update-Database command to use a different appsettings file), please let me know in comment.
I'm faced with this scenario: I want to release my software into production on Azure, but there's a code-first database migration that must be applied at the same time to an Azure SQL database. During the time that new software version is pushed without the new database schema (or vice-versa), there will be a period of time that software will throw the exception The model backing the 'BlogContext' context has changed since the database was created..
My software is deployed upon pushing git commits to a branch using continuous integration in Visual Studio Team Services, so I really need a way to run update-database at the same time.
It appears this can be done using a manual publish from Visual Studio by checking the Update Database box (below), but I need this to be automated.
If you do not care about the data just drop the dbo.__MigrationHistory table
Hope this helps.
Can you take direct control over the deployment process (Team Services can help, or Octopus, Jenkins, others)? If so, deploy the database ahead of the code. That's how I would do it if I wasn't using Entity Framework. I would assume the same even with Entity Framework.
An entity framework context is initialised, by default, using CreateDatabaseIfNotExists<TContext>. If the database schema is different than the EF model, then error The model backing the 'BlogContext' context has changed since the database was created. will be triggered.
By adding to your db context contructor Database.SetInitializer<context>(null); the model error will not be triggered. This means you can deploy schema changes to production, without causing model errors, ahead of the new version of the application being deployed that contains the new db context, which equals no down-time.
Make use of an appSetting so that production code will use the null initializer.
I'm using an orientdb server for developments. Work great. Has classes, about to add support for files, etc. I'm about to provision a server on Azure for orientdb for testing by external people.
Question is
What is the database migration plan as in how to move data between the test database and the development database? Currently, it is just data but soon files will be added. coming from EF background
you can simply make a copy of db folder from test instance to develop.
Alternatively you can do an export (in.gz format) from test and then import in develop
I am trying to find the best way to synchronize/migrate EF Code First databases from localhost to SQL Azure without using EFCF Migrations. I know that I could use this approach, but I want to look at different, less automagic options.
The following process, or variations of such, is the one I'd like to follow:
Develop locally, letting EFCF build the databse on localhost
Synchronize the local database with the stage database on SQL Azure using some tool
Run tests in the staging environment
Synchronze/migrate the database (local or stage) to the production database on SQL Azure
Using MySQL, this is a breeze. The MySQL Workbench can synchronize a schema model to the database in question, plain and simple. In this case, I don't have a schema model per se, but the database on localhost generated by EFCF could be concidered the schema.
Which tools are available to perform this task? Is it possible to do this using SSMS?
Update: How I did it:
After the tip from Craig to use a Visual Studio 2012 Database Project, I did the following:
Created an empty VS 2012 database project and set its target platform to SQL Azure
Did a new schema compare, source database = local db and target = database project
Updated the target. This brought the database project up to speed
Did a new compare, source= database project and target = SQL Azure stage db
Updated the target. This brought the SQL Azure stage db up to speed
This was exactly what I was looking for
The Visual Studio 2012 database project can do it, I do it all the time.
It's not free, but Red-Gate's SQL Compare would handle the schema replication
I guess I should have thought of this before I started my project but I have successfully built and tested a mini application using the code-first approach and I am ready to deploy it to a production web server.
I have moved the folder to my staging server and everything works well. I am just curious if there is a suggested deployment strategy?
If I make a change to the application I don't want to lose all the data if the application is restarted.
Should I just generate the DB scripts from the code-first project and then move it to my server that way?
Any tips and guide links would be useful.
Thanks.
Actually database initializer is only for development. Deploying such code to production is the best way to get some troubles. Code-first currently doesn't have any approach for database evolution so you must manually build change scripts to your database after new version. The easiest approach is using Database tools in VS Studio 2010 Premium and Ultimate. If you will have a database with the old schema and a database with the new schema and VS will prepare change script for you.
Here are the steps I follow.
Comment out any Initialization strategy I'm using.
Generate the database scripts for schema + data for all the tables EXCEPT the EdmMetadata table and run them on the web server. (Of course, if it's a production server, BE CAREFUL about this step. In my case, during development, the data in production and development are identical.)
Commit my solution to subversion which then triggers TeamCity to build, test, and deploy to the web server (of course, you will have your own method for this step, but somehow deploy the website to the web server).
You're all done!
The Initializer and the EdmMetadata tables are needed for development only.