rails/db/migrate/20120320150044_ensure_report_learners_has_indexes.rb
class EnsureReportLearnersHasIndexes < ActiveRecord::Migration[5.1]
def self.up
# remove them first, just in case they exist.
# rescue errors, in case they don't.
remove_index :report_learners, :school_id rescue nil
remove_index :report_learners, :learner_id rescue nil
remove_index :report_learners, :offering_id rescue nil
remove_index :report_learners, :runnable_id rescue nil
remove_index :report_learners, :class_id rescue nil
remove_index :report_learners, :last_run rescue nil
# add them in
add_index :report_learners, :school_id
add_index :report_learners, :learner_id
add_index :report_learners, :offering_id
add_index :report_learners, :runnable_id
add_index :report_learners, :class_id
add_index :report_learners, :last_run
end
def self.down
# don't bother removing them, since the migration earlier has
# been modified to add/remove them.
end
end