this.Property(p => p.Name) .IsRequired() .HasMaxLength(new int?(50)) .HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("UX_Role_Name") { IsUnique=true}));
using System.ComponentModel.DataAnnotations.Schema; [Index(IsUnique = true)]
原文：http://www.cnblogs.com/shiningrise/p/5894205.html