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Over the last six months we’ve released a series of previews of our Code First Migrations work. Today we are making the first fully supported go-live release of our migrations work available as part of EF 4.3.
What Changed Between EF 4.2 and EF 4.3
The notable changes between EF 4.2 and EF 4.3 include:
- New Code First Migrations Feature. This is the primary new feature in EF 4.3 and allows a database created by Code First to be incrementally changed as your Code First model evolves.
- Removal of EdmMetadata table. If you allow Code First to create a database by simply running your application (i.e. without explicitly enabling Migrations) the creation will now take advantage of improvements to database schema generation we have implemented as part of Migrations.
- Bug fix for GetDatabaseValues. In earlier releases this method would fail if your entity classes and context were in different namespaces. This issue is now fixed and the classes don’t need to be in the same namespace to use GetDatabaseValues.
- Bug fix to support Unicode DbSet names. In earlier releases you would get an exception when running a query against a DbSet that contained some Unicode characters. This issue is now fixed.
- Data Annotations on non-public properties. Code First will not include private, protected, or internal properties by default. Even if you manually included these members in your model, using the Fluent API in previous versions of Code First would ignore any Data Annotations on these members. This is now fixed and Code First will process the Data Annotations once the private, protected, or internal properties are manually included in the model.
- More configuration file settings. We’ve enabled more Code First related settings to be specified in the App/Web.config file. This gives you the ability to set the default connection factory and database initializers from the config file. You can also specify constructor arguments to be used when constructing these objects. More details are available in the EF 4.3 Configuration File Settings blog post.
We’ll keep this section updated with issues that are reported on EF 4.3. A few weeks after the EF 4.3 release, we will publish an EF 4.3.1 patch release that includes fixes to some of these issues.
The known issues with the EF 4.3 release include:
- Errors using MOQ to mock DbContext. See this Stack Overflow question for more details. We will be including a fix for this issue in the 4.3.1 patch release.
- TPC mapping generating “Unknown Columnname” exceptions when accessing the database. We will be including a fix for this issue in the 4.3.1 patch release.
- Not all hard coded column data types are honored in generated databases. If you use the Column data annotation or HasColumnType Fluent API method to hard code a column data type (i.e. xml, money, etc.), this data type is not used when creating the database. We will be including a fix for this issue in the 4.3.1 patch release.
What Changed from EF 4.3 Beta 1
Aside from some minor bug fixes the changes to Code First Migrations since EF 4.3 Beta 1 include:
- Enable-Migrations will now scaffold a code-based migration if the database has already been created. If you use Code First to create a database and then later enable migrations, a code-based migration will be scaffolded that represents the objects that have already been created in the database. (See the Enabling Migrations section of the Code-Based Migrations Walkthrough for more details).
You can use the –EnableAutomaticMigrations flag to avoid a code-based migration from being scaffolded, and have the creation of these objects be treated as an automatic migration.
- Added $InitialDatabase constant. This can be used in place of “0” when specifying a source or target migration. For example, migrating down to an empty database can be performed with the Update-Database –TargetMigration:$InitialDatabase command.
- Renamed Update-Database.exe to migrate.exe. The command line tool for applying migrations was originally named to be consistent with the Power Shell command. We’ve now changed it to be more consistent with other command line names.
- Updated migrate.exe so it can be invoked from the NuGet tools folder. In Beta 1 you needed to copy migrate.exe to the same directory as the assembly that contained migrations, you can now invoke it directly from the tools folder. You will need to specify the directory containing your assembly in the /StartUpDirectory parameter. For example:
C:\MyProject\packages\EntityFramework.4.3.0\tools>migrate.exe MyAssembly /StartUpDirectory:C:\MyProject\MyProject\bin\debug
- Fixed errors when running migrations commands from Package Manager Console. A number of folks reported errors when using the migrations commands in certain scenarios. We’ve fixed the underlying bugs causing these issues.
- Fixed –Script issues. There were a number of bugs in the scripting functionality of EF 4.3 Beta 1 that prevented you generating a script starting from a migration other than an empty database. These bugs are now fixed.
You can get EF 4.3 by installing the latest version of the EntityFramework NuGet package.
These existing walkthroughs provide a good introduction to using the Code First, Model First & Database First workflows available in Entity Framework:
There are two new walkthroughs that cover the new Code First Migrations feature. 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 your project for simple changes.
Upgrading from ‘EF 4.3 Beta 1’
If you have EF 4.3 Beta 1 installed you can upgrade to the new package by running Update-Package EntityFramework in Package Manager Console.
You may need to close and re-open Visual Studio after upgrading new package, this is required to unload the old migrations commands.
EF 5.0 (Enum support is coming… finally!)
We’ve been working on a number of features that required updates to some assemblies that are still part of the .NET Framework. These features include enums, spatial data types and some significant performance improvements.
As soon as the next preview of the .NET Framework 4.5 is available we will be shipping EF 5.0 Beta 1, which will include all these new features.
This release can be used in a live operating environment subject to the terms in the license terms. The ADO.NET Entity Framework Forum can be used for questions relating to this release.
ADO.NET Entity Framework Team