CODEWITHSUNDEEP
pythondjango
Abhishek Patil
Abhishek Patil

Reputation: 542

add time when we save a Timefield in django

I have a dateTime field in a model. The dateTime field named breakfast_start_time takes an input. I have to save another variable or timefield(whichever is better) named breakfast_attendence_start_time whose value should be automatically saved 15 minutes less than the breakfast_start_time. For this we use 

def save(self, *args, **kwargs):
    #do something
    super().save(*args, *kwargs)

I am trying to do 

breakfast_attendence_start_time = breakfast_start_time - time(15,0)

but it is giving error that

class TimeField does not define '_sub_', so the '-' operator cannot be used on its instances

Edited:

Here is the full code

class Hostel(models.Model):
    name = models.CharField(max_length=15)
    breakfast_start_time = models.TimeField()
    lunch_start_time = models.TimeField()
    snacks_start_time = models.TimeField()
    dinner_start_time = models.TimeField()

    def save(self, *args, **kwargs):

        super().save(*args, **kwargs)

I am taking start time from admin panel and I want to add 4 more variable/field like breakfast_attendence_start_time whose value should be saved automatically 15 minutes earlier than breakfast_start_time how can I achive that.

Upvotes: 0

Views: 2582

Answers (3)

python manage.py
python manage.py

Reputation: 44

You can play with the DateTimeField but this will return time of when this function was called or used. Hope it helps

from django.utils import timezone
class AKA(models.Model):
create_time = models.DateTimeField(default=timezone.now)
def __str__(self):
        return self.create_time

Upvotes: 0

jpaul
jpaul

Reputation: 317

Use DateTimeField instead of TimeField and use timedelta to make substractions

from datetime import datetime, timedelta
n = datetime(2019, 10, 4, 12, 30)
m = n - timedelta(minutes = 15) # m is now datetime(2019, 10, 4, 12, 15)

Upvotes: 0

Fogmoon
Fogmoon

Reputation: 569

You should use timedelta to sub specific time with DateTime field. Such as 

import datetime

time_before_15_minute = datetime.datetime.now() - datetime.timedelta(minutes=15)

Upvotes: 1

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