diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index e335ab4e0741fdcf10268da9737d9aa8bced8ce6..b440f9b6ba5970da3bfcd6b48a88ef740b0892b8 100755
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -398,6 +398,10 @@ def change_column(table_name, column_name, type, options = {})
         raise NotImplementedError, "change_column is not implemented"
       end
       
+      def change_column_default(table_name, column_name, default)
+        raise NotImplementedError, "change_column_default is not implemented"
+      end
+      
       def supports_migrations?
         false
       end      
@@ -482,7 +486,7 @@ def format_log_entry(message, dump = nil)
         end
       
         def add_column_options!(sql, options)
-          sql << " DEFAULT '#{options[:default]}'" if options[:default]
+          sql << " DEFAULT '#{options[:default]}'" unless options[:default].nil?
         end
     end
 
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 14343b2750c575229fbb75f294ebb3091d22bf35..017e1ba5a5c3563d1d488f0cd259be8ccbb28c20 100755
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -198,9 +198,17 @@ def drop_database(name)
       def create_database(name)
         execute "CREATE DATABASE #{name}"
       end
+      
+      def change_column_default(table_name, column_name, default)
+        current_type = select_one("SHOW COLUMNS FROM #{table_name} LIKE '#{column_name}'")["Type"]
+
+        change_column(table_name, column_name, current_type, { :default => default })
+      end
 
       def change_column(table_name, column_name, type, options = {})
-        change_column_sql = "ALTER TABLE #{table_name} MODIFY #{column_name} #{type}"
+        options[:default] ||= select_one("SHOW COLUMNS FROM #{table_name} LIKE '#{column_name}'")["Default"]
+        
+        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)
         execute(change_column_sql)
       end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 16acf321da5a28081ecf49bc510cc9424a51678d..b7ba2431c4afe2a1f5d755f8f8f8d92875dc96ac 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -151,10 +151,13 @@ def schema_search_path
       end
             
       def change_column(table_name, column_name, type, options = {})
-        change_column_sql = "ALTER TABLE #{table_name} ALTER COLUMN #{column_name} TYPE #{type}"
-        add_column_options!(change_column_sql, options)
-        execute(change_column_sql)
+        execute = "ALTER TABLE #{table_name} ALTER  #{column_name} TYPE #{type}"
+        change_column_default(table_name, column_name, options[:default]) unless options[:default].nil?
       end      
+
+      def change_column_default(table_name, column_name, default)
+        execute "ALTER TABLE #{table_name} ALTER COLUMN #{column_name} SET DEFAULT '#{default}'"
+      end
       
       def rename_column(table_name, column_name, new_column_name)
         execute "ALTER TABLE #{table_name} RENAME COLUMN #{column_name} TO #{new_column_name}"
@@ -163,7 +166,7 @@ def rename_column(table_name, column_name, new_column_name)
       def remove_index(table_name, column_name)
         execute "DROP INDEX #{table_name}_#{column_name}_index"
       end      
-    
+      
       private
         BYTEA_COLUMN_TYPE_OID = 17
 
diff --git a/activerecord/test/migration_test.rb b/activerecord/test/migration_test.rb
index a266afed2f77fe91e3b278b597f57a071d4f75e5..9e849783959a937e478d3a35794a9e4744cc0fa1 100644
--- a/activerecord/test/migration_test.rb
+++ b/activerecord/test/migration_test.rb
@@ -108,9 +108,11 @@ def test_change_column
 
     def test_change_column_with_new_default
       Person.connection.add_column "people", "administrator", :boolean, :default => 1
+      Person.reset_column_information            
       assert Person.new.administrator?
       
       assert_nothing_raised { Person.connection.change_column "people", "administrator", :boolean, :default => 0 }
+      Person.reset_column_information            
       assert !Person.new.administrator?
     end