[eluser]OverZealous[/eluser]
The clear should probably help. I'm not 100% sure it's going to fix it, I've never looped over the same object during a save() — I tend to always load in new objects first.
DataMapper has two ways of working with objects during a save:
• If it is a new object (the id is empty()), then it saves every database column, unless it is NULL. NULL columns are not saved for new objects, to allow DB defaults to be set. (This is a big part of why in-table foreign keys need to be NULL.) The validation routine on runs over all columns on a new object.
• If it is an existing object (id is set), then it only saves the columns that have changed since the last get(). I believe that clear() also resets the changed columns list, but it won't load in the original column data, and it also clears the id. The validation routine runs almost the same, except it always runs over related fields, or fields that were empty() on the last get(). This means you will often get validation errors if the object is not properly loaded.
DataMapper tries to only go to the database when it is asked, selecting on get() and updating on save(). So it won't check to see if a column has changed.
I highly recommend performing a get_by_id() on any existing object you are going to save before you save it, so that DM can properly verify and validate the columns.
