model.py

from django.db import models



class Carbon(models.Model):

    id = models.AutoField(
        primary_key=True,
        editable=False,
        
    )
    meter = models.BigIntegerField()
    reading_date = models.DateField()
    reading_time = models.TimeField()
    reading = models.DecimalField(max_digits=6,decimal_places=2)


    class Meta:

        indexes = [
            models.Index(fields=['id','reading_date','reading_time'])
        ]
        ordering = ['reading_time']

        

    def __str__(self) -> str:
        return self.reading