[英]Active Record Scope modifies Active Record Relation. Why?
Applying a scope to a an Active Record Relation is permanently modifying the relation. 将范围应用于活动记录关系将永久修改该关系。 Why?
为什么?
company_purchases.to_sql
=> "SELECT \"purchases\".* FROM \"purchases\" WHERE \"purchases\".\"company_id\" = 17"
company_purchases.by_state("finalized").to_sql
=> "SELECT \"purchases\".* FROM \"purchases\" WHERE \"purchases\".\"company_id\" = 17 AND \"purchases\".\"state\" = 'finalized'"
company_purchases.to_sql
=> "SELECT \"purchases\".* FROM \"purchases\" WHERE \"purchases\".\"company_id\" = 17 AND \"purchases\".\"state\" = 'finalized'"
I expect the SQL to look different when called on the scope, but I don't understand why the additional where
from the scope remains on the next call to company_purchases
without the scope. 我希望在范围上调用SQL时看起来会有所不同,但是我不明白为什么在下一次对不带范围的
company_purchases
调用时,范围中的其他where
仍然保留。
The scope definition 范围定义
scope :by_state, ->(state) { where(state: state) }
UPDATE 更新
This appears to be a bug with the gem Octopus, see here: https://github.com/thiagopradi/octopus/issues/455 这似乎是宝石章鱼的错误,请参见此处: https : //github.com/thiagopradi/octopus/issues/455
For additional context, the Octopus bug is being introduced because of how company_purchases is composed. 对于其他情况,由于company_purchases的组成方式而引入了章鱼错误。
company_purchases = company.purchases
# in Company model
def purchases
Product.using(shard).where(company_id: id)
end
If you default_scope
than it will display on every query you make on that model. 如果您使用
default_scope
,它将显示在您对该模型进行的每个查询中。 Instead use scope
to avoid above problem. 而是使用
scope
来避免上述问题。
This appears to be an issue with Octopus, not Active Record scopes or relations. 这似乎是八达通的问题,而不是Active Record范围或关系。
See: https://github.com/thiagopradi/octopus/issues/455 参见: https : //github.com/thiagopradi/octopus/issues/455
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