class AddTrackThingsUniqueIndices < ActiveRecord::Migration
    def self.up
        add_index :track_things, [:tracking_user_id, :track_query], :unique => true
        # GRRR - this index confuses Rails migrations, and it makes part of the index but not all
        # of it for the schema.rb, and hence in test databases, and the test databases fail.
        # I guess the query in ./activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
        # needs improving to not detect indices with complex components, rather than detect part of them.
        #execute "create unique index track_things_sent_emails_unique_index on track_things_sent_emails(track_thing_id, coalesce(info_request_event_id, -1), coalesce(user_id, -1), coalesce(public_body_id, -1))"
        #
        # I tried altering config.active_record.schema_format to :sql in config/environment.rb, but
        # got all sorts of other problems with the test user not being a database super user, so gave up again.
    end

    def self.down
        remove_index :track_things, [:tracking_user_id, :track_query]
        #execute "drop index track_things_sent_emails_unique_index"
    end
end