20 lines
716 B
Ruby
20 lines
716 B
Ruby
class StudentsForCourse < ActiveRecord::Base
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attr_accessible :course_id, :student_id
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belongs_to :course, :class_name => 'Course', :foreign_key => :course_id
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belongs_to :student, :class_name => 'User', :foreign_key => :student_id
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validates_presence_of :course_id, :student_id
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validates_uniqueness_of :student_id, :scope => :course_id
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after_destroy :delete_student_works
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def delete_student_works
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course = self.course
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homework_ids = course.homework_commons.blank? ? "(-1)" : "(" + course.homework_commons.map{|hw| hw.id}.join(",") + ")"
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student_works = StudentWork.where("user_id = #{self.student_id} && homework_common_id in #{homework_ids}")
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student_works.destroy_all
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end
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end
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