Is there a way in Django to create and populate a column to the database with a string's length-CodePudding

I have a class/model in my models.py that can receive a textField. I want to add a column in my database that corresponds to the length of this textField. What is the best way of doing that?

CodePudding user response：

You can define a function in your model that returns length of the TextField field. Suppose your model is like this:

class ModelName(models.Model):
    str_field = models.TextField()
    
    @property
    def length(self):
        return (self.str_field)

And my_model is one object of this model class, below code returns length of str_field

my_model.length

CodePudding user response：

You can add a field that stores the character count value to your model:

class YourModel(models.Model):
      my_text_field = models.TextField()
      char_count = models.DecimalField(max_digits=3, decimal_places=0, blank=True, null=True)

And override the model save method to update the field on save:

def save(self, *args, **kwargs):
    self.char_count = len(self.my_text_field)
    super().save(*args, **kwargs)

Adjust the field options (like max_digits) to suit your needs.