一对多关系的Fluent API配置

问题描述

在配置一对多关系时，我通常“仅”从一侧配置关系。但我想知道从双方配置关系会产生什么影响？这是丰富的、模棱两可的还是有任何有意义的影响？

public class Student
{
    public int Id { get; set; }
    public string Name { get; set; }

    public int CurrentGradeId { get; set; }
    public Grade Grade { get; set; }
}

public class Grade
{
    public int GradeId { get; set; }
    public string GradeName { get; set; }
    public string Section { get; set; }

    public ICollection<Student> Students { get; set; }
}

流畅的 API 配置

public class StudentConfiguration : IEntityTypeConfiguration<Student>
    {
        public void Configure(EntityTypeBuilder<Student> builder)
        {
            builder
                .ToTable("Students")
                .HasKey(p => p.Id);

            builder
                .HasOne(student  => student.Grade)
                .WithMany(grade => grade.Students)
                .HasForeignKey(student => student.CurrentGradeId)
        }
    }

public class GradeConfiguration : IEntityTypeConfiguration<Grade>
    {
        public void Configure(EntityTypeBuilder<Grade> builder)
        {
            builder
                .ToTable("Grades")
                .HasKey(p => p.GradeId);

            builder
                .HasMany(grade => grade.Students)
                .WithOne(student => student.Grade)
                .HasForeignKey(student => student.CurrentGradeId)
        }
    }

解决方法

两者都可以。但不能两者兼而有之。 （尽管您似乎交换了“Has...”代码块）。

https://www.learnentityframeworkcore.com/configuration/one-to-many-relationship-configuration