Question

您好我正在实施一个项目。在这个Loan_fines表中引用了两个书籍和类别表。

我收到以下错误： -

NoMethodError in LoanFinesController#create

undefined method `blank' for [1, 1]:Array

app/models/loan_fine.rb:32:in `book_or_category'
app/controllers/loan_fines_controller.rb:46:in `block in create'
app/controllers/loan_fines_controller.rb:45:in `create'

我的贷款罚款表如下： -

  id integer NOT NULL DEFAULT nextval('loans_fines_id_seq'::regclass),
  category_id integer,
  book_id integer,
  loan_duration integer,
  fine_amount numeric(8,2) DEFAULT 0.0,
  fine_duration integer,
  deleted integer NOT NULL DEFAULT 0,
  CONSTRAINT loans_fines_pkey PRIMARY KEY (id)

我的大四学生给了我这张桌子，我不知道nextval('loans_fines_id_seq'::regclass)的含义及其使用原因

我的贷款罚款控制器for create如下： -

 def create
    @loan_fine = LoanFine.new(params[:loan_fine])

    respond_to do |format|
      if @loan_fine.save
        format.html { redirect_to @loan_fine, notice: 'Loan fine was successfully created.' }
        format.json { render json: @loan_fine, status: :created, location: @loan_fine }
      else
        format.html { render action: "new" }
        format.json { render json: @loan_fine.errors, status: :unprocessable_entity }
      end
    end
  end

我的贷款罚款模型如下： -

class LoanFine < ActiveRecord::Base

    attr_accessible :book_id, :category_id, :loan_duration, :fine_amount, :fine_duration

    # ------- ASSOCIATIONS -----------

    belongs_to :book

    belongs_to :category

    # ------ VALIDATIONS ------

    validate :book_or_category

  private

    def book_or_category
        if [self.book_id, self.category_id].compact.blank.size == 0
            errors[:base] << ("Please choose either book or category.")
        end
    end

end

我被困在这上面，我不知道如何实现这一点。任何人都可以帮助我

Answer 1

您的错误在此文件中

app/models/loan_fine.rb

特别是在堆栈跟踪

中指定的第32行

app/models/loan_fine.rb:32:in `book_or_category'

但根据错误，您正在调用blank而不是blank?。所以解决方案是在loan_fine模型的第32行中将blank更改为blank?。

更新：根据您的代码，您希望查看是否存在book_id或category_id。你有2个选择

if self.book_id.blank? && self.category_id.blank?
if [self.book_id, self.category_id].reject(&:blank?).size == 0

获取错误未定义方法`空白'为[1,1]：rails 3.2项目中的数组

1 个答案: