Created
November 8, 2012 14:25
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Reply to Blog post activerecord-black-magic
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# Ref http://spin.atomicobject.com/2012/10/30/activerecord-black-magic/ | |
class EmployeeFinder | |
def self.accessible_by(user) | |
Employee.joins(:companies) \ | |
.merge(Company.where(:id => user.company_ids)) \ | |
.uniq | |
end | |
end | |
UploadedFile.where(uploaded_by: EmployeeFinder.accessible_by(user)) | |
# Alternately, you could also do this and I think most explain plans will find it more effective | |
class EmployeeFinder | |
def self.accessible_by(user) | |
filter = Employee \ | |
.joins(:companies) \ | |
.merge(Company.where_company([1,4])) \ | |
.select(Employee.arel_table[:id]) | |
Employee.where(:id => filter) | |
end | |
end | |
# SQL output | |
>> UploadedFile.by_employees(EmployeeFinder.accessible_by(user)) | |
UploadedFile Load (0.3ms) SELECT "uploaded_files".* FROM "uploaded_files" WHERE "uploaded_files"."employee_id" IN (SELECT "employees"."id" FROM "employees" WHERE "employees"."id" IN (SELECT "employees"."id" FROM "employees" INNER JOIN "companies_employees" ON "companies_employees"."employee_id" = "employees"."id" INNER JOIN "companies" ON "companies"."id" = "companies_employees"."company_id" WHERE "companies"."id" IN (1, 4))) | |
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