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

  name = fields.Char(string="Title", required=True)
    description = fields.Text()

responsible_id = fields.Many2one('res.users',
ondelete='set null', string="Responsible", index=True)


class Session(models.Model):
    _name = 'openacademy.session'
    start_date = fields.Date()
    duration = fields.Float(digits=(6, 2), help="Duration in days")
    seats = fields.Integer(string="Number of seats")

instructor_id = fields.Many2one('res.partner', string="Instructor")
course_id = fields.Many2one('openacademy.course',
    ondelete='cascade', string="Course", required=True)