我有一个具有以下方法的照片模型,可以按名称搜索关联的标签:

class Photo < ActiveRecord::Base
  has_many :taggings, :dependent => :destroy
  has_many :tags, :through => :taggings
  ...

  def self.tagged_with( string )
    array = string.split(',').map{ |s| s.lstrip }
    joins(:tags).where('tags.name' => array ).group(:id)
  end

  ...
end


如果我在控制台中使用它,它的输出将完全符合我的期望:

Photo.tagged_with('foo, bar, baz')
# Returns unique photos with tags named foo, bar, or baz


但是,我尝试使用RSpec中的测试来构建它,但是测试失败。这是我的测试:

describe "tags" do
  it "should return a list of photos matching a string of tags" do
    t1 = Tag.create(:name=>'test')
    t2 = Tag.create(:name=>'bar')
    t1.photos << Photo.find(1,2,3)
    t2.photos << Photo.find(3,4)
    t1.save
    t2.save

    Photo.tagged_with('test').should have(3).photos
    Photo.tagged_with('bar').should have(2).photos
    Photo.tagged_with('test, bar').should have(4).photos
  end
end


该测试失败,并出现以下错误:

  1) Photo tags should return a list of photos matching a string of tags
     Failure/Error: Photo.tagged_with('test').should have(3).photos
     ActiveRecord::StatementInvalid:
       SQLite3::SQLException: ambiguous column name: id: SELECT COUNT(*) AS count_all, id AS id FROM "photos" INNER JOIN "taggings" ON "photos"."id" = "taggings"."photo_id" INNER JOIN "tags" ON "tags"."id" = "taggings"."tag_id" WHERE "tags"."name" IN ('test') GROUP BY id
     # ./spec/models/photo_spec.rb:84:in `block (3 levels) in <top (required)>'


因此,代码有效,但测试失败。我的考试做错了什么?

最佳答案

似乎是在抱怨,因为您按ID分组,并且photo和taggings表都具有id(数据库不知道您是指photos.id还是taggings.id,因此出现“模棱两可”的错误)。尝试在您的agged_with方法中将.group(:id)更改为.group('photos.id')

10-05 20:43
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