Errors using Pomelo MySQL EF provider with ASP.NET Core 2.0 Preview
Let's look at EF Core 2.0 Preview 1 announcement:
If you are using a third party database provider, then check to see if they have released an update that depends on 2.0.0-preview1-final. If they have, then just upgrade to the new version. If not, then you will not be able to upgrade since version 2.0 contains several breaking changes and 1.* providers are not expected to work with it.
That means Pomelo isn't expected to support EF Core 2.0 until a comparatible release is produced.
Recently, faced the same error during my project update to .NET Core 2.0. At this moment, solution is described in https://github.com/PomeloFoundation/Pomelo.EntityFrameworkCore.MySql Basically, update package to the prereleased version 2.0.0-rc-*
<PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="2.0.0-rc-*" />