I need to add a double index to the N to N ratio of the courses_internships table. it would look something like this: add_index[:course_id, :internship_id] .
However, when I created the link table, the index was separated by the columns, not the index being both. How can I reverse this situation?
And ah, I use the has_and_belongs_to_many method
Your new index will be something like: (If you do not need it to be unique, just remove the unique: true from the line).
add_index :courses_internships, [:course_id, :internship_id], unique: true
Already to remove and add the indexes, you can use the following command:
$ rails g migration remove_separated_indexes_and_add_new_to_course_internships
and then edit the migration class with something like:
class RemoveSeparatedIndexesAndAddNewToCourseInternships < ActiveRecord::Migration
def change
remove_index :courses, :course_id
remove_index :internships, :internship_id
add_index :courses_internships, [:course_id, :internship_id], unique: true
end
end
Thanks!