1 @api.onchange('campus_id')

2 def _campus_onchange(self):

3 res = {}

4 res['domain']={'department_id':[('campus_id', '=', self.campus_id.id)]}

5 return res

Today you will learn how to create a dependent drop down (many2one) fields in Odoo . For example I have two many2one fields (campus_id and department_id), and we want to change the department on the basis of campus field.campus_id = fields.Many2one('model.campus', string="Campus Name")department_id = fields.Many2one('model.department', string="Department Name")In line no 1 we use @api.onchange decorator for campus_id. It means whenever campus changes or select a campus from many2one filed do the following line of code (3,4,5). In line no 3 we declare a dict named res. In line no 4 we use domain to change the department field.res['domain'] = {'department_id':[('campus_id', '=', self.campus_id.id)]}| || |(field name which is to changed) (field name which is intended to change)