Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
411 views
in Technique[技术] by (71.8m points)

c# - Does EF Core allow a unique column to contain multiple nulls?

My entity has a property which is allowed to be null. BUT, if it isn't null, then it must be unique. In other words, the column is unique but allows multiple nulls.

I've tried:

config.Property(p => p.ProductId).IsRequired(false);

I remember struggling to get this to work in pre-Core EF.

Is this possible? How do I configure the entity?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Yes, you can do that with EF Core, as a Unique index by default is created as a filtered index (WHERE ... IS NOT NULL)

config.Entity<Product>()
        .HasIndex(b => b.ProductId)
        .IsUnique();

https://github.com/aspnet/EntityFramework/pull/2868


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...