Ruby on rails Rails有“许多:通过PG::Error:Error:column reference”;id";这是一个模棱两可的错误
我是rails新手,我一直在尝试两个has\u-many:虽然需要解决关系(与使用has\u和\u-allown\u-many相反,正如本文所解释的),但现在遇到了一个Postgres错误:Ruby on rails Rails有“许多:通过PG::Error:Error:column reference”;id";这是一个模棱两可的错误,ruby-on-rails,postgresql,has-many-through,Ruby On Rails,Postgresql,Has Many Through,我是rails新手,我一直在尝试两个has\u-many:虽然需要解决关系(与使用has\u和\u-allown\u-many相反,正如本文所解释的),但现在遇到了一个Postgres错误: PG::Error: ERROR: column reference "id" is ambiguous LINE 1: ...on_id" IS NULL AND "components"."id" = 1 ORDER BY id ASC LIM...
PG::Error: ERROR: column reference "id" is ambiguous
LINE 1: ...on_id" IS NULL AND "components"."id" = 1 ORDER BY id ASC LIM...
^
: SELECT 1 AS one FROM "components" INNER JOIN "collection_components" ON "components"."id" = "collection_components"."component_id" WHERE "collection_components"."collection_id" IS NULL AND "components"."id" = 1 ORDER BY id ASC LIMIT 1
Rendered collections/_form.html.haml (117.0ms)
Rendered collections/new.html.haml within layouts/application (143.5ms)
Completed 500 Internal Server Error in 164ms
ActiveRecord::StatementInvalid - PG::Error: ERROR: column reference "id" is ambiguous
LINE 1: ...on_id" IS NULL AND "components"."id" = 1 ORDER BY id ASC LIM...
^
\u form.html.haml
= form_for @collection do |f|
- if @collection.errors.any?
#error_explanation
%h1= "#{pluralize(@collection.errors.count, "error")} prohibited this collection from being saved:"
%ul
- @collection.errors.full_messages.each do |msg|
%li= msg
.field
- Component.all.each do |component|
= label_tag :component_ids, component.id
= check_box_tag :component_ids, component.id, @collection.components.include?(component), :name => 'collection[component_ids][]'
.field
= f.label :title
= f.text_field :title
.actions
= f.submit 'Save'
集合\u组件.rb
class CollectionComponent < ActiveRecord::Base
attr_accessible :collection_id,
:component_id
belongs_to :collection
belongs_to :component
end
class Collection < ActiveRecord::Base
default_scope order('id ASC')
attr_accessible :style_id,
:name,
:title,
:component
#has_and_belongs_to_many :components
has_many :collection_components, :dependent => :destroy
has_many :components, :through => :collection_components
belongs_to :style
validates_presence_of :style
validates_presence_of :title
before_save :create_name
private
def create_name
self.name = title.parameterize
end
end
class Component < ActiveRecord::Base
default_scope order('id ASC')
attr_accessible :category_id,
:name,
:title,
:collection,
:style
has_many :collection_components, :dependent => :destroy
has_many :collections, :through => :collection_components
has_many :component_styles
has_many :styles, :through => :component_styles
belongs_to :category
validates_presence_of :category
validates_presence_of :title
before_save :create_name
private
def create_name
self.name = title.parameterize
end
end
集合表
Column | Type | Modifiers
---------------+-----------------------------+--------------------------------------------------------------------
id | integer | not null default nextval('collection_components_id_seq'::regclass)
collection_id | integer |
component_id | integer |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
Indexes:
"collection_components_pkey" PRIMARY KEY, btree (id)
Column | Type | Modifiers
------------+-----------------------------+----------------------------------------------------------
id | integer | not null default nextval('collections_id_seq'::regclass)
style_id | integer |
name | character varying(255) |
title | character varying(255) |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
Indexes:
"collections_pkey" PRIMARY KEY, btree (id)
Column | Type | Modifiers
-------------+-----------------------------+---------------------------------------------------------
id | integer | not null default nextval('components_id_seq'::regclass)
name | character varying(255) |
title | character varying(255) |
category_id | integer |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
Indexes:
"components_pkey" PRIMARY KEY, btree (id)
组件表
Column | Type | Modifiers
---------------+-----------------------------+--------------------------------------------------------------------
id | integer | not null default nextval('collection_components_id_seq'::regclass)
collection_id | integer |
component_id | integer |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
Indexes:
"collection_components_pkey" PRIMARY KEY, btree (id)
Column | Type | Modifiers
------------+-----------------------------+----------------------------------------------------------
id | integer | not null default nextval('collections_id_seq'::regclass)
style_id | integer |
name | character varying(255) |
title | character varying(255) |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
Indexes:
"collections_pkey" PRIMARY KEY, btree (id)
Column | Type | Modifiers
-------------+-----------------------------+---------------------------------------------------------
id | integer | not null default nextval('components_id_seq'::regclass)
name | character varying(255) |
title | character varying(255) |
category_id | integer |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
Indexes:
"components_pkey" PRIMARY KEY, btree (id)
试试这个:
default_scope { order('collections.id ASC') } //collection.rb
default_scope { order('components.id ASC') } //component.rb
当您在
id
列上执行join
升序时,由于组件
和集合
都有id
列,因此列变得不明确。它将不知道使用哪一个。您只需要在查询中添加字段前的表名
sql方法(“name-of-table.field运算符”)
示例:订单(“collections.id ASC”)
发生这种情况的原因是存在许多同名的字段,而解释器无法识别查询集合中的成员。此外,类别表在设置has_many_Through关系之前已填充,集合表为空。我不确定这是否有区别,但当我生成集合组件模型时,我将其生成为“集合组件”,然后手动删除“s”,手动删除意味着??从何处删除?如中所示,我打开了rb文件,将类名从“CollectionComponents”更改为“CollectionComponent”,并将文件从“collection\u components.rb”重命名为“collection\u component.rb”,打开rails控制台并运行CollectionComponent
。它工作正常吗?我遇到了一个类似的问题,我在没有指定表的情况下创建了一个范围来订购博客文章,当我试图呈现一组片段时,PG变得很热,很麻烦。这就成功了,谢谢。非常感谢!简明扼要的解释!