How to change the data of a table field from another?











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Good evening.
The goal is that when creating the Transfer model, the sum field was subtracted from whom_from and added to whom_to Bill's model. As I understand it, this needs to be done through save (), but apparently, I did not set it up correctly. What could be the problem?



models.py



class Bill(models.Model):
title = models.CharField(max_length=100)
amount = models.DecimalField(max_digits=19, decimal_places=2,
validators=[MinValueValidator(0)], default=0)

def __str__(self):
return self.title


class Transfer(models.Model):
whom_from = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_from')
whom_to = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_to')
sum = models.DecimalField(max_digits=19, decimal_places=2, validators=[MinValueValidator(0)], default=0)

def save(self, *args, **kwargs):
self.whom_to.amount = self.whom_to.amount + self.sum
self.whom_from.amount = self.whom_from.amount - self.sum
super(Transfer, self).save(*args, **kwargs)









share|improve this question


















  • 1




    You need to save whom_to and whom_from after changing their data.
    – Daniel Roseman
    Nov 10 at 19:26










  • @DanielRoseman How to do it?
    – Meekey
    Nov 10 at 20:18






  • 1




    Er, call self.whom_to.save().
    – Daniel Roseman
    Nov 10 at 20:21










  • @DanielRoseman thank you)
    – Meekey
    Nov 10 at 20:29















up vote
0
down vote

favorite












Good evening.
The goal is that when creating the Transfer model, the sum field was subtracted from whom_from and added to whom_to Bill's model. As I understand it, this needs to be done through save (), but apparently, I did not set it up correctly. What could be the problem?



models.py



class Bill(models.Model):
title = models.CharField(max_length=100)
amount = models.DecimalField(max_digits=19, decimal_places=2,
validators=[MinValueValidator(0)], default=0)

def __str__(self):
return self.title


class Transfer(models.Model):
whom_from = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_from')
whom_to = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_to')
sum = models.DecimalField(max_digits=19, decimal_places=2, validators=[MinValueValidator(0)], default=0)

def save(self, *args, **kwargs):
self.whom_to.amount = self.whom_to.amount + self.sum
self.whom_from.amount = self.whom_from.amount - self.sum
super(Transfer, self).save(*args, **kwargs)









share|improve this question


















  • 1




    You need to save whom_to and whom_from after changing their data.
    – Daniel Roseman
    Nov 10 at 19:26










  • @DanielRoseman How to do it?
    – Meekey
    Nov 10 at 20:18






  • 1




    Er, call self.whom_to.save().
    – Daniel Roseman
    Nov 10 at 20:21










  • @DanielRoseman thank you)
    – Meekey
    Nov 10 at 20:29













up vote
0
down vote

favorite









up vote
0
down vote

favorite











Good evening.
The goal is that when creating the Transfer model, the sum field was subtracted from whom_from and added to whom_to Bill's model. As I understand it, this needs to be done through save (), but apparently, I did not set it up correctly. What could be the problem?



models.py



class Bill(models.Model):
title = models.CharField(max_length=100)
amount = models.DecimalField(max_digits=19, decimal_places=2,
validators=[MinValueValidator(0)], default=0)

def __str__(self):
return self.title


class Transfer(models.Model):
whom_from = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_from')
whom_to = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_to')
sum = models.DecimalField(max_digits=19, decimal_places=2, validators=[MinValueValidator(0)], default=0)

def save(self, *args, **kwargs):
self.whom_to.amount = self.whom_to.amount + self.sum
self.whom_from.amount = self.whom_from.amount - self.sum
super(Transfer, self).save(*args, **kwargs)









share|improve this question













Good evening.
The goal is that when creating the Transfer model, the sum field was subtracted from whom_from and added to whom_to Bill's model. As I understand it, this needs to be done through save (), but apparently, I did not set it up correctly. What could be the problem?



models.py



class Bill(models.Model):
title = models.CharField(max_length=100)
amount = models.DecimalField(max_digits=19, decimal_places=2,
validators=[MinValueValidator(0)], default=0)

def __str__(self):
return self.title


class Transfer(models.Model):
whom_from = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_from')
whom_to = models.ForeignKey(Bill, on_delete=models.CASCADE, related_name='whom_to')
sum = models.DecimalField(max_digits=19, decimal_places=2, validators=[MinValueValidator(0)], default=0)

def save(self, *args, **kwargs):
self.whom_to.amount = self.whom_to.amount + self.sum
self.whom_from.amount = self.whom_from.amount - self.sum
super(Transfer, self).save(*args, **kwargs)






python django






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asked Nov 10 at 19:18









Meekey

329




329








  • 1




    You need to save whom_to and whom_from after changing their data.
    – Daniel Roseman
    Nov 10 at 19:26










  • @DanielRoseman How to do it?
    – Meekey
    Nov 10 at 20:18






  • 1




    Er, call self.whom_to.save().
    – Daniel Roseman
    Nov 10 at 20:21










  • @DanielRoseman thank you)
    – Meekey
    Nov 10 at 20:29














  • 1




    You need to save whom_to and whom_from after changing their data.
    – Daniel Roseman
    Nov 10 at 19:26










  • @DanielRoseman How to do it?
    – Meekey
    Nov 10 at 20:18






  • 1




    Er, call self.whom_to.save().
    – Daniel Roseman
    Nov 10 at 20:21










  • @DanielRoseman thank you)
    – Meekey
    Nov 10 at 20:29








1




1




You need to save whom_to and whom_from after changing their data.
– Daniel Roseman
Nov 10 at 19:26




You need to save whom_to and whom_from after changing their data.
– Daniel Roseman
Nov 10 at 19:26












@DanielRoseman How to do it?
– Meekey
Nov 10 at 20:18




@DanielRoseman How to do it?
– Meekey
Nov 10 at 20:18




1




1




Er, call self.whom_to.save().
– Daniel Roseman
Nov 10 at 20:21




Er, call self.whom_to.save().
– Daniel Roseman
Nov 10 at 20:21












@DanielRoseman thank you)
– Meekey
Nov 10 at 20:29




@DanielRoseman thank you)
– Meekey
Nov 10 at 20:29

















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