Entity framework core EFCore数据播种缺少数据插入？

我有两个相关的课程，如下所示：

public class Student
{
    public long Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public long FavoriteCourseId { get; set; }
}

public class Course
{
    public long Id { get; set; }
    public string Name { get; set; }
}

protected override void OnModelCreating(ModelBuilder modelBuilder) {
  modelBuilder.Entity<Student>(entity => {
    entity.ToTable("Student").HasKey(k => k.Id);
    entity.Property(p => p.Id).HasColumnName("StudentID");
    entity.Property(p => p.Name).IsRequired();
    entity.Property(p => p.Email).IsRequired();
    entity.Property(p => p.FavoriteCourseId).IsRequired();
  });

  modelBuilder.Entity<Course>(entity => {
    entity.ToTable("Course").HasKey(k => k.Id);
    entity.Property(p => p.Id).HasColumnName("CourseID");
    entity.Property(p => p.Name).IsRequired();
  });

  modelBuilder.Entity<Student>()
            .HasOne(typeof(Course))
            .WithOne()
            .HasForeignKey("Student", "FavoriteCourseId")
            .HasConstraintName("FK_Student_Course");

  modelBuilder.Entity<Course>().HasData(
            new Course { Id = 1, Name = "Calculus" },
            new Course { Id = 2, Name = "Chemistry" },
            new Course { Id = 3, Name = "Literature" },
            new Course { Id = 4, Name = "Trigonometry" },
            new Course { Id = 5, Name = "Microeconomics" });

  modelBuilder.Entity<Student>().HasData(
     new Student { Id = 1, Name = "Alice", Email = "alice@gmail.com", FavoriteCourseId = 2 },
     new Student { Id = 2, Name = "Bob", Email = "bob@outlook.com", FavoriteCourseId = 2 });
}

两者之间存在一对一的关系

Student

有一个外键，通过

FavoriteCourseId

引用

课程

我的fluent映射如下所示：

public class Student
{
    public long Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public long FavoriteCourseId { get; set; }
}

public class Course
{
    public long Id { get; set; }
    public string Name { get; set; }
}

protected override void OnModelCreating(ModelBuilder modelBuilder) {
  modelBuilder.Entity<Student>(entity => {
    entity.ToTable("Student").HasKey(k => k.Id);
    entity.Property(p => p.Id).HasColumnName("StudentID");
    entity.Property(p => p.Name).IsRequired();
    entity.Property(p => p.Email).IsRequired();
    entity.Property(p => p.FavoriteCourseId).IsRequired();
  });

  modelBuilder.Entity<Course>(entity => {
    entity.ToTable("Course").HasKey(k => k.Id);
    entity.Property(p => p.Id).HasColumnName("CourseID");
    entity.Property(p => p.Name).IsRequired();
  });

  modelBuilder.Entity<Student>()
            .HasOne(typeof(Course))
            .WithOne()
            .HasForeignKey("Student", "FavoriteCourseId")
            .HasConstraintName("FK_Student_Course");

  modelBuilder.Entity<Course>().HasData(
            new Course { Id = 1, Name = "Calculus" },
            new Course { Id = 2, Name = "Chemistry" },
            new Course { Id = 3, Name = "Literature" },
            new Course { Id = 4, Name = "Trigonometry" },
            new Course { Id = 5, Name = "Microeconomics" });

  modelBuilder.Entity<Student>().HasData(
     new Student { Id = 1, Name = "Alice", Email = "alice@gmail.com", FavoriteCourseId = 2 },
     new Student { Id = 2, Name = "Bob", Email = "bob@outlook.com", FavoriteCourseId = 2 });
}

为什么忽略Alice的数据行？我还注意到，只有当Alice和Bob的
FavoriteCourseId
相同时，数据行才会被忽略。如果我将两行的
FavoriteCourseId
更改为不同的值，则Alice将被插入。
它仅为一名学生播种，因为根据您的模型，同一课程只能有一名学生。将模型更改为：

public class Student
{
   [Key]
    public long Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public long FavoriteCourseId { get; set; }
    [ForeignKey(nameof(FavoriteCourseId ))]
     [InverseProperty("FavoriteCourses")]
      public virtual Course FavoriteCourse { get; set; }
}

public class Course
{
    [Key]
    public long Id { get; set; }
    public string Name { get; set; }
    [InverseProperty(nameof(Student.FavoriteCourse))]
    public virtual ICollection<Student> Students{ get; set; }
}


公共班级学生
{
[关键]
公共长Id{get；set；}
公共字符串名称{get；set；}
公共字符串电子邮件{get；set；}
公共长收藏夹CourseId{get；set；}
[ForeignKey（姓名（FavoriteCourseId））]
[反向属性（“偏好课程”）]
公共虚拟课程收藏夹课程{get；set；}
}
公共课
{
[关键]
公共长Id{get；set；}
公共字符串名称{get；set；}
[InverseProperty（姓名（学生最喜欢的课程））]
公共虚拟ICollection学生{get；set；}
}

以及dbcontext：

modelBuilder.Entity<Student>(entity =>
{
 entity.HasOne(d => d.FavoriteCourse)
 .WithMany(p => p.Courses)
 .HasForeignKey(d => d.FavoriteCourseId)
  .OnDelete(DeleteBehavior.ClientSetNull);
}

modelBuilder.Entity<Course>().HasData(
            new Course { Id = 1, Name = "Calculus" },
            new Course { Id = 2, Name = "Chemistry" },
            new Course { Id = 3, Name = "Literature" },
            new Course { Id = 4, Name = "Trigonometry" },
            new Course { Id = 5, Name = "Microeconomics" });

  modelBuilder.Entity<Student>().HasData(
     new Student { Id = 1, Name = "Alice", Email = "alice@gmail.com", FavoriteCourseId = 2 },
     new Student { Id = 2, Name = "Bob", Email = "bob@outlook.com", FavoriteCourseId = 2 });


modelBuilder.Entity（Entity=>
{
entity.HasOne（d=>d.FavoriteCourse）
.有许多（p=>p.课程）
.HasForeignKey（d=>d.FavoriteCourseId）
.OnDelete（DeleteBehavior.ClientSetNull）；
}
modelBuilder.Entity（）.HasData(
新课程{Id=1，Name=“演算”}，
新课程{Id=2，Name=“Chemistry”}，
新课程{Id=3，Name=“文学”}，
新课程{Id=4，Name=“Trigonology”}，
新课程{Id=5，Name=“微观经济学”}）；
modelBuilder.Entity（）.HasData(
新学生{Id=1，Name=“Alice”，Email=”alice@gmail.com，FavoriteCourseId=2}，
新学生{Id=2，Name=“Bob”，Email=”bob@outlook.com“，FavoriteCourseId=2}）；
是的，现在我明白了。