Ruby-on-rails 在 Rails 协会中找不到命名的关联可能是拼写错误的问题
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时间：2020-09-02 22:50:04 来源:igfitidea点击:
association named not found perhaps misspelled issue in rails association
提问by overflow
Here is my controller
这是我的控制器
@post = Post.joins(:customers).select("customers.*,posts.*").find params[:id]
My post model
我的帖子模型
belongs_to :customer
My customer model
我的客户模型
has_many :posts
And i am getting error as
我收到错误
Association named 'customers' was not found on Post; perhaps you misspelled it?
This is my controller output:
这是我的控制器输出：
Processing by PostsController#show as */*
Parameters: {"id"=>"6"}
Post Load (0.5ms) SELECT "posts".* FROM "posts" WHERE "posts"."id" = LIMIT 1 [["id", "6"]]
Completed 500 Internal Server Error in 113ms
ActiveRecord::ConfigurationError (Association named 'customers' was not found on Post; perhaps you misspelled it?):
app/controllers/posts_controller.rb:16:in `show'
回答by MrYoshiji
This is a typical typo error:
这是一个典型的拼写错误：
@post = Post.joins(:customers).select("customers.*,posts.*").find params[:id]
# should be:
@post = Post.joins(:customer).select("customers.*,posts.*").find params[:id]
#^^ no plural
Because you defined the relation like this (using singular):
因为你定义了这样的关系（使用单数）：
# Post model
belongs_to :customer
Some stuff to know:
一些需要了解的内容：
- In the
joins/includesmethod, always use the exact same name as the relation - In the
whereclauses, always use the pluralized name of the relation (actually, the table's name, which is by default the model name in plural but can also be manually set)
- 在
joins/includes方法中，始终使用与关系完全相同的名称 - 在
where子句中，始终使用关系的复数名称（实际上是表的名称，默认情况下是复数形式的模型名称，但也可以手动设置）
Examples:
例子：
# Consider these relations:
User has_many :posts
Post belongs_to :user
# Usage of joins/includes & where:
User.includes(:posts).where(posts: { name: 'BlogPost #1' })
#^ ^
Post.joins(:user).where(users: { name: 'Little Boby Table' })
#^^ ^
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