Modified model data types

diannedelpilar_reading/bookshelf/models.py

@@ -4,20 +4,20 @@ from django.utils import timezone
 class Author(models.Model):
     first_name = models.CharField(max_length=50)
     last_name = models.CharField(max_length=50)
-    age = models.IntegerField(default = 0)
+    age = models.PositiveIntegerField()
     nationality = models.CharField(max_length=100)
     bio = models.TextField(max_length=700)
 
     def __str__(self):
-        return self.first_name, self.last_name
+        return self.first_name + ' ' + self.last_name
 
 
 class Book(models.Model):
     title = models.CharField(max_length=300)
     author = models.ForeignKey(Author, on_delete = models.CASCADE)
-    publisher = models.CharField(max_length=100)
-    year_published = models.DateTimeField(default=timezone.now, null=True, blank=True)
-    ISBN = models.IntegerField(default = 0000000000000)
+    publisher = models.CharField(max_length=100, default = None)
+    year_published = models.PositiveIntegerField()
+    ISBN = models.PositiveIntegerField()
     blurb = models.TextField(max_length=200)
 
     def __str__(self):