I\'m writing a seed method using EntityFramework.Core 7.0.0-rc1-final.
What happened to the AddOrUpdate method of DbSet?
I've found a nice solution that allows you specify the property that should match. However, it doesn't take a single entity, but a list in each call. It may give you some hints on how to implement a better version that works like the good-olde one.
https://github.com/aspnet/MusicStore/blob/7787e963dd0b7293ff95b28dcae92407231e0300/samples/MusicStore/Models/SampleData.cs#L48
(Code isn't mine)