Function Doctrine::loadData() can only append data to the database, and can’t reload data, because function Doctrine_Data ->purge() need model names for delete data.
Without model names function purge() don’t delete any data from database.
Place, where we know model names for loading data, is Doctrine_Data_Import->doImport().
That is why we must pass $append argument from Doctrine::loadData() to Doctrine_Data_Import->doImport().
Because loading data may be related and has foreign key constraint, the list of the models must be reversed before data will be deleted.

Problem was detected in symfony 1.1 framework.