Question

我有以下has_many：通过情况：

class User < ApplicationRecord
  has_many :term_enrollments, foreign_key: 'builder_id'
  has_many :terms, through: :term_enrollments
end

class TermEnrollment < ApplicationRecord
  belongs_to :term
  belongs_to :builder, class_name: 'User'
end

class Term < ApplicationRecord
    has_many :builder_term_enrollments, class_name: 'TermEnrollment', foreign_key: 'builder_id'
    has_many :builders, through: :builder_term_enrollments, source: :builder
end

以下成功创建了term_enrollment：

u = User.first
t = Term.first
u.terms << t

然后我可以成功运行u.terms。问题是如果我运行t.builders，我得到一个空关联：

=> #<ActiveRecord::Associations::CollectionProxy []>

我很确定我错误地使用source，但我不确定如何使用[Table("EMPLOYMENT")] public class Employment { private DateTime _StartDate; [Column("STARTDATE")] public DateTime StartDate { get { return _StartDate; } set { _StartDate = value; StartMonth = value.ToString("MMMM") ?? null; } } [Column("STARTMONTH")] public string StartMonth { get; set; } }。我该如何解决这个问题？

Answer 1

您可以尝试将:builder_term_enrollments中的外键设置为'term_id'或:term_id吗？

这将使ActiveRecord能够找到具有相应term_id的任何行。

Answer 2

重写术语模型修复它：

class Term < ApplicationRecord
    has_many :builder_term_enrollments, class_name: 'TermEnrollment', source: :builder
    has_many :builders, through: :builder_term_enrollments
end

has_many：通过只在一个方向工作

2 个答案: