canvas-lms/db/migrate/20120201044246_purge_duplic...

32 lines
1.0 KiB
Ruby

class PurgeDuplicateDeletedSisEnrollments < ActiveRecord::Migration
def self.up
if supports_ddl_transactions?
commit_db_transaction
decrement_open_transactions while open_transactions > 0
end
while true
pairs = Enrollment.connection.select_rows("
SELECT user_id, course_section_id, type
FROM enrollments
WHERE workflow_state='deleted' AND sis_source_id IS NOT NULL
GROUP BY user_id, course_section_id, type
HAVING count(*) > 1 LIMIT 1000")
break if pairs.empty?
pairs.each do |(user_id, course_section_id, type)|
scope = Enrollment.scoped(:conditions => ["user_id=? AND course_section_id=? AND type=? AND sis_source_id IS NOT NULL AND workflow_state='deleted'", user_id.to_i, course_section_id.to_i, type])
keeper = scope.first(:select => :id)
scope.delete_all(["id<>?", keeper.id])
end
end
if supports_ddl_transactions?
increment_open_transactions
begin_db_transaction
end
end
def self.down
end
end