from django.db import models class Classification(models.Model): code = models.CharField(max_length=10) class Employee(models.Model): name = models.CharField(max_length=40, blank=False, null=False) salary = models.PositiveIntegerField() department = models.CharField(max_length=40, blank=False, null=False) hire_date = models.DateField(blank=False, null=False) age = models.IntegerField(blank=False, null=False) classification = models.ForeignKey('Classification', on_delete=models.CASCADE, null=True)