Model extra attributes

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In some case you may want to access a column which is not owned by the model itself. This can be provided by access attributes hash on the model.
In this case, you should set the optional argument fetch_columns to true during the fetching:
In the example below, we want to display a the identification document type and number for each person:
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People.query.left_join("identification_documents"){ 
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    peoples.id == identification_documents.person_id
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}.select(
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    "people.*", 
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    "identification_documents.type AS doc_type",
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    "identification_documents.number AS doc_number"
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).each(fetch_columns: true) do |x|
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    puts "Person #{x.full_name}: " +
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         "#{x.attributes["doc_type"]} - #{x.attributes["doc_number"]}"
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end
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The optional parameter fetch_columns is available in most of the methods where we fetch to one or multiple models.
fetch_columns reduces slightly the performance of the ORM, and that's why it's set to false by default.
This can be combined also with aggregate functions access, like counter:
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customers = Customer.query
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    .join("shippings"){ shippings.customer_id == customer.id  }
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    .select("customers.*", "COUNT(shippings.*) as shipping_count")
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​
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customers.each(fetch_columns: true) do |x|
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    puts "customer #{x.id} => #{x.attributes["shipping_count"]}"
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end
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Cursored fetching
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Last modified 3yr ago
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