class GtopicBank < ApplicationRecord
  belongs_to :user
  belongs_to :graduation_topic, optional: true
  belongs_to :course_list, optional: true

  has_many :attachments, as: :container, dependent: :destroy
  has_many :graduation_topics, dependent: :nullify

  scope :myself, ->(user_id) { where(user_id: user_id)}


  # 课题名称和描述字段长度限制
  validates :name, length: { maximum: 60, too_long: "不能超过60个字符" }
  validates :description, length: { maximum: 5000, too_long: "不能超过5000个字符" }
end