Custom field default value - populate with other entries from same field - odoo

Question

I have created a custom module with extra fields on the product screen. I am trying to have the default value be a drop down with all of the entries already submitted to that field or the option to create a new entry (same as the default value when adding a product to a BOM).
class product_part_detail(osv.osv):
_inherit = 'product.template'
_columns = {
'x_mfrname1': fields.char('P/N'),
}
_defaults ={
'x_mfrname1': get_default_name,
}
def get_default_name(self):
return "test"
I tried creating a many2one field that refers to a field in a different table but I keep getting an error when trying to install the module. Below is the updated code that I am having issues with. Thanks in advance!
class product_part_detail(osv.osv):
_inherit = 'product.template'
_name = 'product.part.detail'
_columns = {
'x_mfrname1': fields.many2one('product.part.detail.fill', 'x_mfrname1id'),
'x_mfrname2': fields.many2one('product.part.detail.fill', 'x_mfrname1id'),
}
class product_part_detail_fill(osv.osv):
_name = 'product.part.detail.fill'
def _sel_func(self, cr, uid, context=None):
obj = self.pool.get('product.part.detail')
ids = obj.search(cr, uid, [])
res = obj.read(cr, uid, ids, ['x_mfrname1', 'x_mfrname2'], context)
res = [(r['x_mfrname1'], r['x_mfrname2']) for r in res]
return res
_columns = {
'x_mfrname1id': fields.one2many('product.part.detail', 'x_mfrname1', 'x_mfrname2', selection=_sel_func),
}

Answer 1

A couple of things. The idea of a drop down of the values they have previously entered requires a many2one field. You would create another model and then make x_mfrname1 a many2one to that table. As long as the user has create access on that table they will get a create option on the drop down to key new values.
One other item, as you are using the pre-8 API, the method signature of your default method should be:
def get_default_name(self, cr, uid, context=None):