Purpose of package "Microsoft.EntityFrameworkCore.Design"

Question

All tutorials agree that project.json should include:

"Microsoft.EntityFrameworkCore.Design":  {      "type":"build",      "version":"1.0.0-preview2-final"  } 

I have never included it, and have never had a problem.

I only include

"Microsoft.EntityFrameworkCore" "Microsoft.EntityFrameworkCore.Sqlite"   (or Sqlserver) "Microsoft.EntityFrameworkCore.Tools" 

What does this package do? Why can I exclude it without problems?

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UPDATE: see comments in accepted answer to figure out which package to import in which scenario.

Answer 1

Microsoft.EntityFrameworkCore.Design contains all the design-time logic for Entity Framework Core. It's the code that all of the various tools (PMC cmdlets like Add-Migration, dotnet ef & ef.exe) call into.

If you don't use Migrations or Reverse Engineering, you don't need it.

And when you do need it, we encourage PrivateAssets="All" so it doesn't get published to the server where you almost certainly won't need it.