2 files changed, 4 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 7a697c2335..417eca180e 100755
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -308,7 +308,9 @@ module ActiveRecord
       end
 
       def change_column(table_name, column_name, type, options = {}) #:nodoc:
-        options[:default] ||= select_one("SHOW COLUMNS FROM #{table_name} LIKE '#{column_name}'")["Default"]
+        if options[:default].nil?
+          options[:default] = select_one("SHOW COLUMNS FROM #{table_name} LIKE '#{column_name}'")["Default"]
+        end
         
         change_column_sql = "ALTER TABLE #{table_name} CHANGE #{column_name} #{column_name} #{type_to_sql(type, options[:limit])}"
         add_column_options!(change_column_sql, options)
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index ba219b9799..cf4114aacc 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -243,7 +243,7 @@ module ActiveRecord
           definition[column_name].instance_eval do
             self.type    = type
             self.limit   = options[:limit] if options[:limit]
-            self.default = options[:default] if options[:default]
+            self.default = options[:default] unless options[:default].nil?
           end
         end
       end