canvas-lms/db/migrate/20110803192001_unread_counts.rb

#
# Copyright (C) 2011 - present Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.

class UnreadCounts < ActiveRecord::Migration[4.2]
  tag :predeploy

  def self.up
    add_column :users, :unread_conversations_count, :int, :default => 0
    update <<-SQL
    UPDATE #{User.quoted_table_name}
    SET unread_conversations_count = (
      SELECT COUNT(*)
      FROM #{ConversationParticipant.quoted_table_name}
      WHERE workflow_state = 'unread'
        AND last_message_at IS NOT NULL
        AND user_id = users.id
    )
    SQL
  end

  def self.down
    remove_column :users, :unread_conversations_count
  end
end