Don't run non pg compatible migrations on empty tables

db/migrate/20110328202414_post_visibilities_on_contacts.rb

@@ -57,7 +57,11 @@ SQL
   end
 
   def self.pv_count
-    @pv_count ||= execute('SELECT count(*) FROM post_visibilities').to_a.first.first
+    @pv_count ||= lambda {
+      count = execute('SELECT count(*) FROM post_visibilities').to_a.first.first
+      count = count.last.to_i if self.connection.class == ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
+      count
+    }.call
   end
 
   def self.up

db/migrate/20110330230206_pm_foreign_keys.rb

@@ -1,4 +1,7 @@
 class PmForeignKeys < ActiveRecord::Migration
+  class Message < ActiveRecord::Base
+  end
+
   def self.delete_disconnected_cvs
     execute <<SQL
     DELETE conversation_visibilities FROM conversation_visibilities
@@ -23,7 +26,7 @@ SQL
 SQL
   end
   def self.up
-    if execute('SELECT COUNT(*) FROM messages').to_a.first.first > 0
+    if Message.count > 0
       delete_disconnected_conversations
       delete_disconnected_messages
       delete_disconnected_cvs

db/migrate/20110405171412_contact_remove_pending_add_sharing_and_receiving.rb

@@ -1,21 +1,25 @@
 class ContactRemovePendingAddSharingAndReceiving < ActiveRecord::Migration
+  class Contact < ActiveRecord::Base; end
+
   def self.up
     add_column :contacts, :sharing, :boolean, :default => false, :null => false
     add_column :contacts, :receiving, :boolean, :default => false, :null => false
 
-    execute( <<SQL
-      UPDATE contacts
-        SET contacts.sharing = true, contacts.receiving = true
-          WHERE contacts.pending = false
+    if Contact.count > 0
+      execute( <<SQL
+        UPDATE contacts
+          SET contacts.sharing = true, contacts.receiving = true
+            WHERE contacts.pending = false
 SQL
 )
 
-    execute( <<SQL
-      DELETE user_preferences.* FROM user_preferences
-        WHERE user_preferences.email_type = 'request_acceptance'
-          OR user_preferences.email_type = 'request_received'
+      execute( <<SQL
+        DELETE user_preferences.* FROM user_preferences
+          WHERE user_preferences.email_type = 'request_acceptance'
+            OR user_preferences.email_type = 'request_received'
 SQL
 )
+    end
 
     remove_foreign_key "contacts", "people"
     remove_index :contacts, [:person_id, :pending]

db/migrate/20110406202932_drop_requests_table.rb

@@ -1,4 +1,6 @@
 class DropRequestsTable < ActiveRecord::Migration
+  class Contact < ActiveRecord::Base; end
+
   def self.up
     remove_foreign_key :requests, :column => :recipient_id
     remove_foreign_key :requests, :column => :sender_id
@@ -14,7 +16,7 @@ class DropRequestsTable < ActiveRecord::Migration
       DELETE contacts.* FROM contacts
         WHERE contacts.sharing = false
 SQL
-)
+    ) if Contact.count > 0
   end
 
   def self.down

db/migrate/20110406203720_tag_name_uniqueness.rb

@@ -1,4 +1,6 @@
 class TagNameUniqueness < ActiveRecord::Migration
+  class Tag < ActiveRecord::Base; end
+
   def self.downcase_tags
     execute <<SQL
       UPDATE tags
@@ -30,8 +32,10 @@ SQL
   end
 
   def self.up
-    downcase_tags
-    consolidate_duplicate_tags
+    if Tag.count > 0
+      downcase_tags
+      consolidate_duplicate_tags
+    end
     add_index :tags, :name, :unique => true
   end
 

db/migrate/20110421120744_downcase_usernames.rb

@@ -1,6 +1,8 @@
 class DowncaseUsernames < ActiveRecord::Migration
+  class User < ActiveRecord::Base; end
+
   def self.up
-    execute <<SQL
+    execute <<SQL if User.count > 0
       UPDATE users
       SET users.username = LOWER(users.username)
       WHERE users.username != LOWER(users.username)

db/migrate/20110513175000_eliminate_stray_user_records.rb

@@ -1,5 +1,8 @@
 class EliminateStrayUserRecords < ActiveRecord::Migration
+  class User < ActiveRecord::Base; end
+
   def self.up
+    return unless User.count > 0
     duplicated_emails = execute("SELECT LOWER(email) from users WHERE users.email != '' GROUP BY LOWER(email) HAVING COUNT(*) > 1").to_a
     duplicated_emails.each do |email|
       records = execute("SELECT users.id, users.username, users.created_at from users WHERE LOWER(users.email) = '#{email}'").to_a

db/migrate/20110517180148_delete_all_new_request_notifications.rb

@@ -1,6 +1,7 @@
 class DeleteAllNewRequestNotifications < ActiveRecord::Migration
+  class Notification < ActiveRecord::Base; end
   def self.up
-    execute <<SQL
+    execute <<SQL if Notification.count > 0
       DELETE notifications.* FROM notifications
       WHERE notifications.type = 'Notifications::NewRequest'
         OR notifications.type = 'Notifications::RequestAccepted'

db/migrate/20110518010050_disable_password_reset_for_accounts_without_usernames.rb

@@ -1,6 +1,7 @@
 class DisablePasswordResetForAccountsWithoutUsernames < ActiveRecord::Migration
+  class User < ActiveRecord::Base; end
   def self.up
-    execute <<SQL
+    execute <<SQL if User.count > 0
       UPDATE users
         SET email = ""
       WHERE username IS NULL

db/migrate/20110524184202_add_object_id_to_post.rb

@@ -1,10 +1,11 @@
 class AddObjectIdToPost < ActiveRecord::Migration
+  class Post < ActiveRecord::Base; end
   def self.up
     add_column(:posts, :objectId, :integer)
-    execute("UPDATE posts SET objectId = object_url")
+    execute("UPDATE posts SET objectId = object_url") if Post.count > 0
   end
 
   def self.down
-    add_column(:posts, :objectId, :integer)
+    remove_column(:posts, :objectId, :integer)
   end
 end

db/schema.rb

@@ -81,7 +81,7 @@ ActiveRecord::Schema.define(:version => 20110606192307) do
     t.datetime "updated_at"
   end
 
-  add_index "conversation_visibilities", ["conversation_id", "person_id"], :name => "index_conversation_visibilities_on_conversation_id_and_person_id", :unique => true
+  add_index "conversation_visibilities", ["conversation_id", "person_id"], :name => "index_conversation_visibilities_on_everything", :unique => true
   add_index "conversation_visibilities", ["conversation_id"], :name => "index_conversation_visibilities_on_conversation_id"
   add_index "conversation_visibilities", ["person_id"], :name => "index_conversation_visibilities_on_person_id"
 
@@ -93,8 +93,6 @@ ActiveRecord::Schema.define(:version => 20110606192307) do
     t.datetime "updated_at"
   end
 
-  add_index "conversations", ["author_id"], :name => "conversations_author_id_fk"
-
   create_table "invitations", :force => true do |t|
     t.text     "message"
     t.integer  "sender_id",    :null => false
@@ -119,7 +117,6 @@ ActiveRecord::Schema.define(:version => 20110606192307) do
     t.datetime "updated_at"
   end
 
-  add_index "likes", ["author_id"], :name => "likes_author_id_fk"
   add_index "likes", ["guid"], :name => "index_likes_on_guid", :unique => true
   add_index "likes", ["post_id"], :name => "index_likes_on_post_id"
 
@@ -144,7 +141,6 @@ ActiveRecord::Schema.define(:version => 20110606192307) do
   end
 
   add_index "messages", ["author_id"], :name => "index_messages_on_author_id"
-  add_index "messages", ["conversation_id"], :name => "messages_conversation_id_fk"
 
   create_table "notification_actors", :force => true do |t|
     t.integer  "notification_id"