CODEWITHSUNDEEP
ef-code-firstentity-framework-5code-first
Trae Thompson
Trae Thompson

Reputation: 21

How to use Migration Commands for Entity Framework through User Defined Code

I need to be able to perform all of the available functions that the Package Manager Console performs for code first DB migrations. Does anyone know how I could accomplish these commands strictly through user defined code? I am trying to automate this whole migration process and my team has hit the dreaded issue of getting the migrations out of sync due to the number of developers on this project. I want to write a project that the developer can interact with that will create and if need be rescaffold their migrations for them automatically.

Upvotes: 2

Views: 1114

Answers (2)

Avi Cherry
Avi Cherry

Reputation: 4096

At least as of this post, you can directly access the System.Data.Entity.Migrations.Design.MigrationScaffolder class and directly call the Scaffold() methods on it, which will return you an object that contains the contents of the "regular" .cs file, the "Designer.cs" file and the .resx file.

What you do with those files is up to you!

Personally, I'm attempting to turn this into a tool that will be able to create EF6 migrations on a new ASPNET5/DNX project, which is not supported by the powershell commands.

Upvotes: 0

NSGaga
NSGaga

Reputation: 14302

PM is invoking through PowerShell and PS cmdlets (like for active directory etc.)
http://docs.nuget.org/docs/reference/package-manager-console-powershell-reference

The Package Manager Console is a PowerShell console within Visual Studio

...there is essentially very little info about this - I've tried that before on couple occasions and it gets down to doing some 'dirty work' if you really need it (not really sure, it might not be that difficult - providing you have some PS experience)

Here are similar questions / answers - working out the PS comdlets is pretty involving - in this case it has some additional steps involved. And PS tends to get very version dependent - so you need to check this for the specific EF/CF you're using.

Run entityframework cmdlets from my code

Possible to add migration using EF DbMigrator

And you may want to look at the source code for EF that does Add-Migration
(correction: this is the link to official repository - thanks to @Brice for that)  

http://entityframework.codeplex.com/SourceControl/changeset/view/f986cb32d0a3#src/EntityFramework.PowerShell/Migrations/AddMigrationCommand.cs

http://entityframework.codeplex.com/SourceControl/BrowseLatest

(PM errors also suggest the origins of the code doing the Add-Migrations to be the 'System.Data.Entity.Migrations.Design.ToolingFacade')

If you need 'just' an Update - you could try using the DbMigrator.Update (this guy gave it a try http://joshmouch.wordpress.com/2012/04/22/entity-framework-code-first-migrations-executing-migrations-using-code-not-powershell-commands/) - but I'm not sure how relevant is that to you, I doubt it.
The scaffolding is the real problem (Add-Migration) which to my knowledge isn't accessible from C# directly via EF/CF framework.

Note: - based on the code in (http://entityframework.codeplex.com/SourceControl/changeset/view/f986cb32d0a3#src/EntityFramework.PowerShell/Migrations/AddMigrationCommand.cs) - and as the EF guru mentioned himself - that part of the code is calling into the System.Data.Entity.Migrations.Design library - which does most of the stuff. If it's possible to reference that one and actually repeat what AddMigrationCommand is doing - then there might not be a need for PowerShell at all. But I'm suspecting it's not that straight-forward, with possible 'internal' calls invisible to outside callers etc.

Upvotes: 1

Related Questions