- required fields may sometimes be provided by alternative columns, and all the alternatives are therefore not required (e.g. for a m2o the CSV can provide m2o or m2o/id columns) - when fields share the same label, precedence when matching column headers should be given to the field with the exact same name, rather than just the first one encountered bzr revid: odo@openerp.com-20120606174043-f1nmkad3p17mccyy