How to override the query in has_many relationship












1














I need to override the defailt ActiveRecord generated SQL query in a has_many relationship. While finder_sql is deprecated in Rails 4.



In a given legacy application there are multiple relationships between customers and their available discounts. It looks like this:



data model



A Rails 4 scope on discounts to fetch all available discounts for a given customer:



scope :for_customer, lambda { |customer|
where("CustomerNo = '#{customer.CustomerNo}'
OR DiscountGrpCustNo = '#{customer.DiscountGrpCustNo}'
OR PriceListNo = '#{customer.PriceListNo}'")
}


So I wanted to use this scope to define the has_many on the customer.
I found an explanation for using variables on a has_many in a different question here: https://stackoverflow.com/a/2462397/1062276



So I tried:



has_many :discounts,
-> (customer) { for_customer(customer) }


Which resulted in Invalid column name 'customer_id' due to the following:



> customer.discounts.to_sql
SELECT [KuraasAS].[DiscountAgreementCustomer].* FROM [KuraasAS].[DiscountAgreementCustomer] WHERE [KuraasAS].[DiscountAgreementCustomer].[customer_id] = 12345 AND (CustomerNo = '12345'
OR DiscountGrpCustNo = '5'
OR PriceListNo = '3')


The customer_id column is Rails's assumption. How can I take this out of the query?










share|improve this question



























    1














    I need to override the defailt ActiveRecord generated SQL query in a has_many relationship. While finder_sql is deprecated in Rails 4.



    In a given legacy application there are multiple relationships between customers and their available discounts. It looks like this:



    data model



    A Rails 4 scope on discounts to fetch all available discounts for a given customer:



    scope :for_customer, lambda { |customer|
    where("CustomerNo = '#{customer.CustomerNo}'
    OR DiscountGrpCustNo = '#{customer.DiscountGrpCustNo}'
    OR PriceListNo = '#{customer.PriceListNo}'")
    }


    So I wanted to use this scope to define the has_many on the customer.
    I found an explanation for using variables on a has_many in a different question here: https://stackoverflow.com/a/2462397/1062276



    So I tried:



    has_many :discounts,
    -> (customer) { for_customer(customer) }


    Which resulted in Invalid column name 'customer_id' due to the following:



    > customer.discounts.to_sql
    SELECT [KuraasAS].[DiscountAgreementCustomer].* FROM [KuraasAS].[DiscountAgreementCustomer] WHERE [KuraasAS].[DiscountAgreementCustomer].[customer_id] = 12345 AND (CustomerNo = '12345'
    OR DiscountGrpCustNo = '5'
    OR PriceListNo = '3')


    The customer_id column is Rails's assumption. How can I take this out of the query?










    share|improve this question

























      1












      1








      1







      I need to override the defailt ActiveRecord generated SQL query in a has_many relationship. While finder_sql is deprecated in Rails 4.



      In a given legacy application there are multiple relationships between customers and their available discounts. It looks like this:



      data model



      A Rails 4 scope on discounts to fetch all available discounts for a given customer:



      scope :for_customer, lambda { |customer|
      where("CustomerNo = '#{customer.CustomerNo}'
      OR DiscountGrpCustNo = '#{customer.DiscountGrpCustNo}'
      OR PriceListNo = '#{customer.PriceListNo}'")
      }


      So I wanted to use this scope to define the has_many on the customer.
      I found an explanation for using variables on a has_many in a different question here: https://stackoverflow.com/a/2462397/1062276



      So I tried:



      has_many :discounts,
      -> (customer) { for_customer(customer) }


      Which resulted in Invalid column name 'customer_id' due to the following:



      > customer.discounts.to_sql
      SELECT [KuraasAS].[DiscountAgreementCustomer].* FROM [KuraasAS].[DiscountAgreementCustomer] WHERE [KuraasAS].[DiscountAgreementCustomer].[customer_id] = 12345 AND (CustomerNo = '12345'
      OR DiscountGrpCustNo = '5'
      OR PriceListNo = '3')


      The customer_id column is Rails's assumption. How can I take this out of the query?










      share|improve this question













      I need to override the defailt ActiveRecord generated SQL query in a has_many relationship. While finder_sql is deprecated in Rails 4.



      In a given legacy application there are multiple relationships between customers and their available discounts. It looks like this:



      data model



      A Rails 4 scope on discounts to fetch all available discounts for a given customer:



      scope :for_customer, lambda { |customer|
      where("CustomerNo = '#{customer.CustomerNo}'
      OR DiscountGrpCustNo = '#{customer.DiscountGrpCustNo}'
      OR PriceListNo = '#{customer.PriceListNo}'")
      }


      So I wanted to use this scope to define the has_many on the customer.
      I found an explanation for using variables on a has_many in a different question here: https://stackoverflow.com/a/2462397/1062276



      So I tried:



      has_many :discounts,
      -> (customer) { for_customer(customer) }


      Which resulted in Invalid column name 'customer_id' due to the following:



      > customer.discounts.to_sql
      SELECT [KuraasAS].[DiscountAgreementCustomer].* FROM [KuraasAS].[DiscountAgreementCustomer] WHERE [KuraasAS].[DiscountAgreementCustomer].[customer_id] = 12345 AND (CustomerNo = '12345'
      OR DiscountGrpCustNo = '5'
      OR PriceListNo = '3')


      The customer_id column is Rails's assumption. How can I take this out of the query?







      ruby-on-rails sql-server activerecord override






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      asked Nov 22 at 9:34









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          To override the default generated query in a Rails 4 has_many relationship I did the following:



          has_many :discounts,
          -> (cu) { unscope(:where).for_customer(cu) }


          The method to look up and make use of is unscope






          share|improve this answer





















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            1 Answer
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            1 Answer
            1






            active

            oldest

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            active

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            active

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            0














            To override the default generated query in a Rails 4 has_many relationship I did the following:



            has_many :discounts,
            -> (cu) { unscope(:where).for_customer(cu) }


            The method to look up and make use of is unscope






            share|improve this answer


























              0














              To override the default generated query in a Rails 4 has_many relationship I did the following:



              has_many :discounts,
              -> (cu) { unscope(:where).for_customer(cu) }


              The method to look up and make use of is unscope






              share|improve this answer
























                0












                0








                0






                To override the default generated query in a Rails 4 has_many relationship I did the following:



                has_many :discounts,
                -> (cu) { unscope(:where).for_customer(cu) }


                The method to look up and make use of is unscope






                share|improve this answer












                To override the default generated query in a Rails 4 has_many relationship I did the following:



                has_many :discounts,
                -> (cu) { unscope(:where).for_customer(cu) }


                The method to look up and make use of is unscope







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 22 at 9:37









                ringe

                632311




                632311






























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