Active Record persistence

Legend:

    => in the meaning column means there's a non-boolean return value
    empty columns in Prior Name mean the method didn't exist before
    * before a new method name means it's an alias to the prior method

Prior Name 			New Name 					Meaning
attribute_was(attr_name) 	*attribute_in_database(attr_name) 		current database value of attribute
attribute_change(attr_name) 	*attribute_change_to_be_saved 			=> the changed value for attribute
attribute_changed?(attr_name) 	*will_save_change_to_attribute?(attr_name) 	was attribute modified since last save
	attribute_before_last_save(attr_name) 	=> attribute value from before last save
changed 	*changed_attribute_names_to_save 	=> name of attributes with changed values since last save
changes 	*changes_to_save 	=> the changes to be saved to DB
changed? 	*has_changes_to_save? 	are there any changes to be saved to the DB?
changed_attributes 	*attributes_in_database 	=> Hash of attribute names & new unsaved values
changed? 	has_changes_to_save? 	record has unsaved changes
	saved_changes? 	did last save change record attributes?
	saved_changes 	=> Hash of all changes in last save
	saved_change_to_attribute?(attr_name) 	did attribute change when record last saved?
	saved_change_to_attribute(attr_name) 	=> array of original & saved value from last save