If you want to make data model in OpenERP(Odoo) follow the below mentioned code and paste it in your model.py file:

session_ids = fields.One2many(
        'openacademy.session', 'course_id', string="Sessions")

    @api.multi
    def copy(self, default=None):
        default = dict(default or {})

        copied_count = self.search_count(
            [('name', '=like', u"Copy of {}%".format(self.name))])
        if not copied_count:
            new_name = u"Copy of {}".format(self.name)
        else:
            new_name = u"Copy of {} ({})".format(self.name, copied_count)

        default['name'] = new_name
        return super(Course, self).copy(default)

    _sql_constraints = [
        ('name_description_check',
         'CHECK(name != description)',