mysql - 在 MySQL Rails 4 中使用数组

Question

我正在尝试更改我的“seeker_cvs”表列“location_id”。它是一个整数类型。现在我想把它做成一个数组。 (我被迫在没有多对多关联的情况下做到这一点)。所以我的模型是:

class SeekerCv < ActiveRecord::Base

  belongs_to :location, class_name: 'Category'
  serialize :location_id, Array

end

类别有很多 seeker_cvs。

我还添加并运行了新的迁移:

class ChangeLocationIdOnSeekerCvs < ActiveRecord::Migration
  def change
    change_column :seeker_cvs, :location_id, :integer, array: true, default: []
  end
end 

在 seekers_cvs Controller 中，我已将许可“location_id”更改为“location_id:[]”:

class SeekerCvsController < ApplicationController

  def new
    @cv = SeekerCv.new
  end

  def create
    @cv = SeekerCv.new(cv_params)
    @cv.seeker = current_seeker
    if @cv.save
      redirect_to seeker_cv_path(@cv)
    else
      render :new
    end
  end

  def edit
    @cv = SeekerCv.find(params[:id])
    authorize @cv
  end

  def update
    @cv = SeekerCv.find(params[:id])
    @cv.attributes = cv_params
    if @cv.save
      redirect_to seeker_cv_path(@cv)
    else
      render :edit
    end
  end

  private

  def cv_params
    params.require(:seeker_cv).permit :name,
                                      :category_id,
                                      :no_experience,
                                      location_id: []
  end
end

在 View 中我添加了 multiple: true 到 form:

= simple_form_for @cv, html: { class: 'form-horizontal' } do |f|
  .panel.panel-default
    .panel-heading
      h3.panel-title = t('.cv_name')
    .panel-body#cv-category
      = f.input :name
      = f.input :category_id do
        = f.select :category_id,
          nested_set_options_opt_mod(Category.category.root.children.to_a) { |i| "#{'-' * i.level} #{i.name}" },
          { disabled: Category.category.find_all { |l| !l.leaf? }.map(&:id), include_blank: true },
          { class: 'form-control' }
      = f.input :location_id do
        = f.select :location_id,
          nested_set_options_opt(Category.location.root) { |i| "#{'-' * i.level} #{i.name}" },
          { disabled: Category.location.root.id, include_blank: true }, 
          { multiple: true, class: 'form-control' }

但是当我尝试创建或更新 seeker_cv(见图)时，我得到:

ActiveRecord::SerializationTypeMismatch at /app/en/seeker_cvs
Attribute was supposed to be a Array, but was a Fixnum. -- 0

附言我需要保存以前创建的 seeker_cvs 和整数类型的 location_id。并且新的或更新的必须具有数组类型的列

Answer 1

问题是 mysql 没有本地数组类型。所以你必须使用 varchar 作为列类型

change_column :seeker_cvs, :location_id, :string