diff --git a/db/migrate/019_add_issue_status_position.rb b/db/migrate/019_add_issue_status_position.rb
index 1c65e52e3..ed24d27c1 100644
--- a/db/migrate/019_add_issue_status_position.rb
+++ b/db/migrate/019_add_issue_status_position.rb
@@ -1,6 +1,6 @@
 class AddIssueStatusPosition < ActiveRecord::Migration
   def self.up
-    add_column :issue_statuses, :position, :integer, :default => 1, :null => false
+    add_column :issue_statuses, :position, :integer, :default => 1
     IssueStatus.find(:all).each_with_index {|status, i| status.update_attribute(:position, i+1)}
   end
 
diff --git a/db/migrate/020_add_role_position.rb b/db/migrate/020_add_role_position.rb
index 3afa88193..e220bd9fd 100644
--- a/db/migrate/020_add_role_position.rb
+++ b/db/migrate/020_add_role_position.rb
@@ -1,6 +1,6 @@
 class AddRolePosition < ActiveRecord::Migration
   def self.up
-    add_column :roles, :position, :integer, :default => 1, :null => false
+    add_column :roles, :position, :integer, :default => 1
     Role.find(:all).each_with_index {|role, i| role.update_attribute(:position, i+1)}
   end
 
diff --git a/db/migrate/021_add_tracker_position.rb b/db/migrate/021_add_tracker_position.rb
index 30a5d771c..ef9775620 100644
--- a/db/migrate/021_add_tracker_position.rb
+++ b/db/migrate/021_add_tracker_position.rb
@@ -1,6 +1,6 @@
 class AddTrackerPosition < ActiveRecord::Migration
   def self.up
-    add_column :trackers, :position, :integer, :default => 1, :null => false
+    add_column :trackers, :position, :integer, :default => 1
     Tracker.find(:all).each_with_index {|tracker, i| tracker.update_attribute(:position, i+1)}
   end
 
diff --git a/db/migrate/045_create_boards.rb b/db/migrate/045_create_boards.rb
index b8647c812..17f2bbbe2 100644
--- a/db/migrate/045_create_boards.rb
+++ b/db/migrate/045_create_boards.rb
@@ -4,7 +4,7 @@ class CreateBoards < ActiveRecord::Migration
       t.column :project_id, :integer, :null => false
       t.column :name, :string, :default => "", :null => false
       t.column :description, :string
-      t.column :position, :integer, :default => 1, :null => false
+      t.column :position, :integer, :default => 1
       t.column :topics_count, :integer, :default => 0, :null => false
       t.column :messages_count, :integer, :default => 0, :null => false
       t.column :last_message_id, :integer
diff --git a/db/migrate/072_add_enumerations_position.rb b/db/migrate/072_add_enumerations_position.rb
index 6f2a93219..e0beaf395 100644
--- a/db/migrate/072_add_enumerations_position.rb
+++ b/db/migrate/072_add_enumerations_position.rb
@@ -1,6 +1,6 @@
 class AddEnumerationsPosition < ActiveRecord::Migration
   def self.up
-    add_column(:enumerations, :position, :integer, :default => 1, :null => false) unless Enumeration.column_names.include?('position')
+    add_column(:enumerations, :position, :integer, :default => 1) unless Enumeration.column_names.include?('position')
     Enumeration.find(:all).group_by(&:opt).each_value  do |enums|
       enums.each_with_index do |enum, i|
         # do not call model callbacks