text: import datetime
  
  from django.db import models
  from django.utils import timezone
  
  
  class Employee(models.Model):
      name = models.CharField(max_length=200)
      employee_id = models.AutoField(primary_key=True)
  
      def __str__(self):
          return f'{self.name}'
  
  
  class BioData(models.Model):
      employee = models.OneToOneField(Employee, on_delete=models.CASCADE)
      age = models.IntegerField()
      sex = models.CharField(max_length=20)
  
      def __str__(self):
          return f'{self.employee.name}'
  
  
  class Payroll(models.Model):
      employee = models.OneToOneField(Employee, on_delete=models.CASCADE)
      salary = models.FloatField()
  
      def __str__(self):
          return f'{self.employee.name}'
  