Question

我在EF核心中存在多对多关系的问题。我有以下型号：

   public class Institution
    {
        [Key]
        public int Id { get; set; }

        [JsonIgnore]
        public virtual ICollection<InstitutionDepartment> InstitutionDepartments { get; set; }
    }


    public class InstitutionDepartment
    {
        [Column("Institution_Id")]
        public int InstitutionId { get; set; }
        [Column("Department_Id")]
        public int DepartmentId { get; set; }

        public Institution Institution { get; set; }
        public Departments Department { get; set; }
    }

    public class Departments
    {
        [Key]
        public int Id { get; set; }
        public string Name { get; set; }
        public bool Published { get; set; }

        [JsonIgnore]
        public virtual ICollection<InstitutionDepartment> InstitutionDepartments { get; set; }
    }

我遵循了许多教程，其中解释了如何正确映射这些类：

     modelBuilder.Entity<InstitutionDepartment>()
        .HasKey(x => new { x.DepartmentId, x.InstitutionId});

    modelBuilder.Entity<InstitutionDepartment>()
        .HasOne(pt => pt.Institution)
        .WithMany(p => p.InstitutionDepartments)
        .HasForeignKey(pt => pt.InstitutionId);

    modelBuilder.Entity<InstitutionDepartment>()
        .HasOne(pt => pt.Department)
        .WithMany(t => t.InstitutionDepartments)
        .HasForeignKey(pt => pt.DepartmentId);

我写了我的查询：

    var institutions = _context.Institutions
        .Include(i => i.InstitutionDepartments)
        .ThenInclude(id => id.Department);

但是无论我做什么，都会出现以下错误： Invalid column name 'InstitutionId'.

有人可以告诉我我在做什么错吗？ D：

注意，如果我不写.ThenInclude(id => id.Department);部分，则不会收到错误消息。但这会使数据不完整

Answer 1

问题出在我当时认为不相关的一行代码（下次我会知道的）

这是在Institution模型中，没有[NotMapped]批注：

        [NotMapped]
        public IEnumerable<Departments> Departments
            => InstitutionDepartments?.Select(o => o.Department);

这导致EF在Institution和Department之间寻找缺少的一对多关系

列名称的多对多关系问题-EF Core

1 个答案: