The information in this post is out of date.
Visit msdn.com/data/ef for the latest information on current and past releases of EF.
For Code First Migrations see http://msdn.com/data/jj591621
A couple of weeks ago we released Alpha 2 of Code First Migrations. Today we are happy to make Alpha 3 available to you.
The overall feedback we got on Alpha 2 was that you like the direction we are headed. We heard that there is definitely a use case for automatic migrations, and while not everyone will use them, we should continue to invest in them. You are asking us to look at the story for data migration that doesn’t involve dropping down to SQL. Alpha 2 also had some commonly encountered bugs that were annoying and we needed to fix
Alpha 3 is still is primarily focused on the developer experience inside of Visual Studio. This release adds most of development time features we plan to include in the first RTM. Your feedback will guide any changes we make to the overall design. Apart from responding to your feedback our team is starting to focus on improving quality. We are also working on completing the deployment and team-build stories, including a command line tool and an MSDeploy provider.
Alpha 3 is focused on adding the remaining features that you have been asking for around development time migrations. The primary changes in Alpha 3 are:
- VB.NET migration generation is now available.
- Upgrade/Downgrade to any migration is now available via the –TargetMigration switch.
- Seed data can now be added by overriding the Seed method of the Settings class. Data is expressed in terms of the current model and the Seed method is called after upgrading to the latest migration.
- We removed TargetDatabase from the Settings class. Instead you can use the –TargetDatabase switch to specify the name of a connection string from your App/Web.config file.
- You can now start using Code First Migrations against an existing database that was created by Code First. To do this issue an Update-Database command when you model is the same as the model that created the database. To use this feature the EdmMetadata table must be present in the database. This original creation of the database and tables will be counted as an automatic migration, if you want a code-based migration for the initial create of the database and tables you must drop the database and begin using migrations against an empty or non-existent database.
- Improved error logging when an exception is encountered.
- The bugs that required SQL Compact and SQL Express to be available are now resolved.
Some known issues, and ‘yet to be implemented’ features include:
- Code-based migrations and databases generated with Alpha 2 cannot be used with Alpha 3. Because Alpha 2 was such an early release we needed to make some changes to the table we use to store migrations and the way we generate and identify code-based migrations. If you were using Alpha 2 you will need to regenerate migrations and run them to create your database. We realize this is painful but it is one of the trade-offs associated with getting previews into your hands early in the development process. We are making an effort to reduce such changes in future previews.
- If you are updating the EntityFramework.Migrations package you will need to close and re-open Visual Studio after updating. This is required to reload the updated command assemblies.
- No outside-of-Visual-Studio experience. Alpha 2 only includes the Visual Studio integrated experience. We also plan to deliver a command line tool and an MSDeploy provider for Code First Migrations.
We really want your feedback on Code First Migrations. Is the solution we are delivering what you want? Are there features we should add? Please comment on this post with any feedback you might have.
There are two walkthroughs for Alpha 3, one focuses on the no-magic workflow that uses a code-based migration for every change. The other looks at using automatic migrations to avoid having lots of code in you project for simple changes.
- Code First Migrations: Alpha 3 ‘No-Magic’ Walkthrough
- Code First Migrations: Alpha 3 ‘With-Magic’ Walkthrough (Automatic Migrations)
Prerequisites & Incompatibilities
Migrations is dependent on EF 4.1 Update 1, this updated release of EF 4.1 will be automatically installed when you install the EntityFramework.Migrations package.
Important: If you have previously run the EF 4.1 stand alone installer you will need to upgrade or remove the installation before using migrations. This is required because the installer adds the EF 4.1 assembly to the Global Assembly Cache (GAC) causing the original RTM version to be used at runtime rather than Update 1.
This release is incompatible with “Microsoft Data Services, Entity Framework, and SQL Server Tools for Data Framework June 2011 CTP”.
This is a preview of features that will be available in future releases and is designed to allow you to provide feedback on the design of these features. It is not intended or licensed for use in production. If you need assistance we have an Entity Framework Pre-Release Forum.
ADO.NET Entity Framework Team