当我在模板中显示数据时，如何解决 Django 中的价格错误？

Question

I am trying to convert price in Lac and crore in Indian numbering system . Value is stored in minprice' in this format ( 10000000 ), then it will display on my homepage in this format ( 1 cr ), but I am getting this error ( '>=' not supported between instances of 'NoneType' and 'int' `) in my website whenever I open any project. How can I solve this issue?

Here is my models.py file:

class Project(models.Model):
    name=models.CharField(null=True, 
                          max_length=114,
                          help_text=f"Type: string, Values: Enter Project Name.")

    slug=models.SlugField(null=True, 
                          unique=True,
                          max_length=114,
                          help_text=f"Type: string, Values: Enter Project Slug.")

here is my related model name, project has OneToOne relation with details :

class Detail(models.Model):
        project = models.OneToOneField(Project, related_name='project_details', on_delete=models.CASCADE)
        minprice = models.IntegerField(null=True,
                                    blank=True,
                                    verbose_name="Minimum Price",
                                    help_text=f"Type: Int, Values: Enter Minimum Price")
        
        
        maxprice = models.IntegerField(null=True,
                                    blank=True, 
                                    verbose_name='Maximum Price',
                                    help_text=f"Type: Int, Values: Enter Maximum Price")    
        @property                            
        def min_price_tag(self):
            if self.minprice >=1000 and self.minprice <=99999:
                self.minprice=self.minprice//1000
                return f"{self.minprice} K"  
            elif self.minprice>=100000 and self.minprice<=9999999:
                self.minprice=self.minprice//100000
                return f"{self.minprice} Lac" 
            else:
                self.minprice=self.minprice/10000000
                return f'{self.minprice} Cr'
            return str(self.minprice) if self.minprice is not None else ""    
    
        @property                            
        def max_price_tag(self):
            if self.maxprice >=1000 and self.maxprice <=99999:
                self.maxprice=self.maxprice//1000
                return f"{self.maxprice} K"  
            elif self.maxprice>=100000 and self.maxprice<=9999999:
                self.maxprice=self.maxprice//100000
                return f"{self.maxprice} Lac" 
            else:
                self.maxprice=self.maxprice/10000000
                return f'{self.maxprice} Cr'
            return str(self.maxprice) if self.maxprice is not None else "" 

here is my project.html file, where I am displaying the data

{% for i in project %}
    <div class="col-md-3 col-sm-12">
    <div class="single-property-box">
        <a class="trend-right float-right">
            <div class="trend-open">
                <p>
                    ₹ {{i.project_details.min_price_tag}} - ₹{{i.project_details.max_price_tag}}
                </p>
            </div>
        </a>
   </div>
    </div>
 {% endfor %} 

Answer 1

The error might be occurring because you have set both the integer fields null=True, blank=True, make them required.