clear disconnected records in migration

db/migrate/20110228201109_foreign_key_constraints.rb

 class ForeignKeyConstraints < ActiveRecord::Migration
+  def self.disconnected_records dependent_table, dep_column, parent_table
+    result = execute <<SQL
+SELECT #{dependent_table}.id FROM #{dependent_table}
+LEFT OUTER JOIN #{parent_table} ON #{dependent_table}.#{dep_column} = #{parent_table}.id
+WHERE #{parent_table}.id IS NULL;
+SQL
+    result.to_a.flatten!
+  end
+
+  def self.delete_disconnected_records dependent_table, dep_column, parent_table
+    bad_ids = disconnected_records dependent_table, dep_column, parent_table
+    return unless bad_ids
+    execute <<SQL
+DELETE FROM #{dependent_table}
+WHERE #{dependent_table}.id IN (#{bad_ids.join(',')}
+SQL
+  end
+
   def self.up
+    [['aspect_memberships', 'contact_id', 'contacts'],
+     ['aspect_memberships', 'aspect_id', 'aspects'],
+     ['comments', 'post_id', 'posts'],
+     ['comments', 'person_id', 'people'],
+     ['posts', 'person_id', 'people'],
+     ['contacts', 'person_id', 'people'],
+     ['invitations', 'sender_id', 'users'],
+     ['invitations', 'recipient_id', 'users'],
+     ['notification_actors', 'notification_id', 'notifications'],
+     ['profiles', 'person_id', 'people'],
+     ['requests', 'sender_id', 'people'],
+     ['requests', 'recipient_id', 'people'],
+     ['services', 'user_id', 'users']
+    ].each do |array|
+      delete_disconnected_records array[0], array[1], array[2]
+    end
+
     add_foreign_key(:aspect_memberships, :contacts, :dependent => :delete)
     add_foreign_key(:aspect_memberships, :aspects, :dependent => :restrict)