ruby-on-rails – Rails / postgres,“外键”存储在数组中以创建

但是,如果要更快地搜索/过滤分配给用户的任务,您可以在“任务”对象中保留一组用户标识.否则,您必须在标准关联表中执行JOIN以查找分配给Alice的所有任务.

因此,解决方案是保留关联表,但也将受让人用户ID复制到Task对象中,并使用该ID列表进行更快的搜索/过滤.

您将需要挂接到受让人对象的after_create和after_destroy生命周期,并将新的受理人ID插入到任务记录数组中.然后当一个asignee从任务中删除时更新数组以删除ID.

有关所有Array操作符,请参阅Postgres文档：

这样的事情

class Task < ActiveRecord::Base
    has_many :assignees,:dependent => :destroy
end

class Asignee < ActiveRecord::Base

    belongs_to :task
    after_create :insert_task_assignee
    after_destroy :remove_task_assignee

    # assumes that there is a column called assignee_id
    # that contains the User ID of the assigned person

    private

    def insert_task_assignee
        # TODO: check for duplicates here - before we naively push it on?
        task.assignee_list = task.assignee_list.push(assignee_id)
        task.assignee_list.save
    end

    def remove_task_assignee
        id_list = task.assignee_list
        id_list.reject! { |candidate_id| candidate_id == assignee_id }
        task.assignee_list = id_list
        task.assignee_list.save
    end

end

# find all tasks that have been assigned Alice & Bob
# this will require the `postgres_ext` gem for Ruby / Postgres array searching
tasks = Task.where.contains(:assignee_list => [alice.id,bob.id]).all