def _alter_set_defaults(self, field, name, params, sqls):
        # Historically, we used to set defaults here.
        # But since South 0.8, we don't ever set defaults on alter-column -- we only
        # use database-level defaults as scaffolding when adding columns.
        # However, we still sometimes need to remove defaults in alter-column.
        sqls.append(('ALTER COLUMN %s DROP DEFAULT' % (self.quote_name(name),), []))
Subcommand of alter_column that sets default values (overrideable)
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/South-1.0.2/south/db/generic.py/DatabaseOperations._alter_set_defaults