using Microsoft.EntityFrameworkCore; using Microsoft.EntityFrameworkCore.Metadata.Builders; namespace EntityFrameworkCore.Jet.IntegrationTests.Model09 { public class TwoMap : IEntityTypeConfiguration { public void Configure(EntityTypeBuilder builder) { builder.HasKey(t => new { t.Id, t.OneId }); builder.ToTable("Two"); //builder.HasRequired(t => t.One).WithMany(t => t.TwoList).HasForeignKey(t => t.OneId); // Now has required is obtained setting OneId as required (not nullable) builder.HasOne(t => t.One).WithMany(t => t.TwoList).HasForeignKey(t => t.OneId); } } }