diff --git a/db/migrate/048_allow_null_version_effective_date.rb b/db/migrate/048_allow_null_version_effective_date.rb
index 4b46bfe0e..82d2a33ec 100644
--- a/db/migrate/048_allow_null_version_effective_date.rb
+++ b/db/migrate/048_allow_null_version_effective_date.rb
@@ -1,6 +1,6 @@
 class AllowNullVersionEffectiveDate < ActiveRecord::Migration
   def self.up
-    change_column :versions, :effective_date, :date, :default => nil
+    change_column :versions, :effective_date, :date, :default => nil, :null => true
   end
 
   def self.down
diff --git a/db/migrate/076_allow_null_position.rb b/db/migrate/076_allow_null_position.rb
index 45008d653..ece0370db 100644
--- a/db/migrate/076_allow_null_position.rb
+++ b/db/migrate/076_allow_null_position.rb
@@ -1,11 +1,11 @@
 class AllowNullPosition < ActiveRecord::Migration
   def self.up
     # removes the 'not null' constraint on position fields
-    change_column :issue_statuses, :position, :integer, :default => 1
-    change_column :roles, :position, :integer, :default => 1
-    change_column :trackers, :position, :integer, :default => 1
-    change_column :boards, :position, :integer, :default => 1
-    change_column :enumerations, :position, :integer, :default => 1
+    change_column :issue_statuses, :position, :integer, :default => 1, :null => true
+    change_column :roles, :position, :integer, :default => 1, :null => true
+    change_column :trackers, :position, :integer, :default => 1, :null => true
+    change_column :boards, :position, :integer, :default => 1, :null => true
+    change_column :enumerations, :position, :integer, :default => 1, :null => true
   end
 
   def self.down
diff --git a/db/migrate/087_change_projects_description_to_text.rb b/db/migrate/087_change_projects_description_to_text.rb
index 2829655d1..b06b0aa1c 100644
--- a/db/migrate/087_change_projects_description_to_text.rb
+++ b/db/migrate/087_change_projects_description_to_text.rb
@@ -1,6 +1,6 @@
 class ChangeProjectsDescriptionToText < ActiveRecord::Migration
   def self.up
-    change_column :projects, :description, :text
+    change_column :projects, :description, :text, :null => true
   end
 
   def self.down