Onchange, Compute method, Constrains on Date fields in Odoo 11

1. Date calculation "compute" method  in Odoo 11

with Starting date and Ending date fields.

Calculates No of days => days between starting date  and ending date.
To calculate how many days project task completed.

Conditions:

1. Start date greater than or equal to today
2. Start date should not be greater than Ending date

@api.one@api.depends('start_date', 'end_date')
def _date_calc(self):
    if self.start_date and self.end_date:
        d1 = datetime.strptime(str(self.start_date), '%Y-%m-%d')
        d2 = datetime.strptime(str(self.end_date), '%Y-%m-%d')
        today_date = datetime.now().date()
        pd = datetime.strptime(str(today_date), '%Y-%m-%d')
        if d1 < pd:
            raise UserError("Start date should not be less than Today.")
        if d1 <= d2:
            d3 = d2 - d1
            self.number_of_days = str(d3.days + 1)
        else:
            self.number_of_days = 0

            raise UserError("Start date should be less than end date.")
    else:
        self.number_of_days = 0

start_date = fields.Date(string='Start Date')
end_date = fields.Date(string='End Date')

number_of_days = fields.Char(string='No. of Days', compute='_date_calc')

@api.one@api.depends('start_date', 'end_date')
def _date_calc(self):
    if self.start_date and self.end_date:
        d1 = datetime.strptime(str(self.start_date), '%Y-%m-%d')
        d2 = datetime.strptime(str(self.end_date), '%Y-%m-%d')
        today_date = datetime.now().date()
        pd = datetime.strptime(str(today_date), '%Y-%m-%d')
        if d1 < pd:
            raise UserError("Start date should not be less than Today.")
        if d1 <= d2:
            d3 = d2 - d1
            self.number_of_days = str(d3.days + 1)
        else:
            self.number_of_days = 0 

            raise UserError("Start date should be less than end date.")
    else:
        self.number_of_days = 0

Example

2. On change Date field in Odoo 11

@api.onchange('start_date')
def onchange_date(self):
    print("onchange start date......")
    if self.start_date:
        sd = datetime.strptime(str(self.start_date), '%Y-%m-%d')
        ed = datetime.strptime(str(self.start_date), '%Y-%m-%d')
        today_date = datetime.now().date()
        pd = datetime.strptime(str(today_date), '%Y-%m-%d')

        if sd < pd:
            print("sd is lesser than pd --> Abnormal")
            self.start_date = datetime.now().date()
            return {
                'warning': {
                    'title': "Error in Date Selection", 

                    'message': "Starting date should not be lesser than today",                }
                    }
        elif sd > ed:
            print("Elif --> Sd is greater than ed --> Abnormal")
            self.start_date = self.start_date = datetime.now().date()
            return {
                'warning': {
                    'title': "Error in Date Selection", 

                    'message': "Starting date should not be greater than Ending Date", 

                           }
                    }
        else:
            print("Every thing right onchange start date....")



 

@api.onchange('end_date')
def onchange_date(self):
        print("onchange end date.....")
        if self.end_date:
            ed = datetime.strptime(str(self.end_date), '%Y-%m-%d')
            sd = datetime.strptime(str(self.start_date), '%Y-%m-%d')
            

            if ed < sd:
                print("End date is lesser than Start date -- Abnormal ")
                self.end_date = self.start_date
                return {
                    'warning': {
                        'title': "Error in Date Selection", 

                        'message': "Ending date should not be lesser than Starting date", 

                               }
                        }

3. Constrains on Date field in Odoo11

 

@api.constrains('start_date', 'end_date')
def validate_date(self):
    """Checking the start and end dates of the syllabus, 

      raise warning if start date is not anterior"""  

    for rec in self:   

         if rec.start_date > rec.end_date:
            raise ValidationError(_('Start date should not come after End date'))