[英]rails includes multiple 2 level associations
I have a table invoices with a column PRODUCT. 我有带有PRODUCT列的表格发票。 Products table then belongs to other tables such as categories, suppliers etc.. 然后,产品表属于其他表,例如类别,供应商等。
In my view I need to display: 在我看来,我需要显示:
invoice.product.CATEGORY
inventory.product.SUPPLIER
I am trying to setup my controller to avoid n+1 queries. 我正在尝试设置控制器以避免n + 1个查询。
So I did: 所以我做了:
@invoices = Invoice.all.includes(product => category, product => supplier)
I have bullet gem installed, and it shows that there/sa n+1 query detected Product => [category]
and Add to your finder::includes => [:category]
我已经安装了bullet gem,它表明存在/一个n + 1查询检测到Product => [category]
并Add to your finder::includes => [:category]
It seems considering only the latest of the includes and ignore the others. 似乎只考虑了最新的内容,而忽略了其他内容。 I suppose my syntax is wrong. 我想我的语法是错误的。
How can I fix it? 我该如何解决?
You didn't symbolize your models. 您没有象征模型。
@invoices = Invoice.all.includes(:product => :category, :product => :supplier)
This can be shortened by using an array: 这可以通过使用数组来缩短:
@invoices = Invoice.all.includes(:product => [:category, :supplier])
It's idiomatic to put your .where
or .limit
(or .all
) at the end: 这是习惯把你的.where
或.limit
(或.all
)结尾:
@invoices = Invoice.includes(:product => [:category, :supplier]).all
Why not make a scope? 为什么不做范围?
controller 控制者
def index
@invoices = Invoice.with_details.all
end
model 模型
class Invoice
# ...
def self.with_details
includes(:product => [:category, :supplier])
end
end
Even better: 更好的是:
controller 控制者
def index
@invoices = Invoice.with_details(params[:qty])
end
model 模型
class Invoice
# ...
def self.with_details(num)
includes(:product => [:category, :supplier]).limit(num)
end
end
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