137 lines
4.7 KiB
Python
137 lines
4.7 KiB
Python
from django.db import models
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# Create your models here.
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from django.urls import reverse #Used to generate urls by reversing the URL patterns
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class Genre(models.Model):
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"""
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Model representing a book genre (e.g. Science Fiction, Non Fiction).
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"""
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name = models.CharField(max_length=200, help_text="Enter a book genre (e.g. Science Fiction, French Poetry etc.)")
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def __str__(self):
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"""
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String for representing the Model object (in Admin site etc.)
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"""
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return self.name
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class Language(models.Model):
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"""
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Model representing a Language (e.g. English, French, Japanese, etc.)
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"""
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name = models.CharField(max_length=200, help_text="Enter a the book's natural language (e.g. English, French, Japanese etc.)")
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def __str__(self):
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"""
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String for representing the Model object (in Admin site etc.)
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"""
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return self.name
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class Book(models.Model):
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"""
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Model representing a book (but not a specific copy of a book).
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"""
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title = models.CharField(max_length=200)
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author = models.ForeignKey('Author', on_delete=models.SET_NULL, null=True)
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# Foreign Key used because book can only have one author, but authors can have multiple books
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# Author as a string rather than object because it hasn't been declared yet in file.
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summary = models.TextField(max_length=1000, help_text="Enter a brief description of the book")
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isbn = models.CharField('ISBN',max_length=13, help_text='13 Character <a href="https://www.isbn-international.org/content/what-isbn">ISBN number</a>')
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genre = models.ManyToManyField(Genre, help_text="Select a genre for this book")
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# ManyToManyField used because Subject can contain many books. Books can cover many subjects.
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# Subject declared as an object because it has already been defined.
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language = models.ForeignKey('Language', on_delete=models.SET_NULL, null=True)
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def display_genre(self):
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"""
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Creates a string for the Genre. This is required to display genre in Admin.
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"""
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return ', '.join([ genre.name for genre in self.genre.all()[:3] ])
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display_genre.short_description = 'Genre'
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def get_absolute_url(self):
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"""
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Returns the url to access a particular book instance.
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"""
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return reverse('book-detail', args=[str(self.id)])
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def __str__(self):
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"""
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String for representing the Model object.
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"""
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return self.title
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import uuid # Required for unique book instances
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from datetime import date
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from django.contrib.auth.models import User #Required to assign User as a borrower
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class BookInstance(models.Model):
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"""
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Model representing a specific copy of a book (i.e. that can be borrowed from the library).
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"""
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id = models.UUIDField(primary_key=True, default=uuid.uuid4, help_text="Unique ID for this particular book across whole library")
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book = models.ForeignKey('Book', on_delete=models.SET_NULL, null=True)
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imprint = models.CharField(max_length=200)
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due_back = models.DateField(null=True, blank=True)
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borrower = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, blank=True)
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@property
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def is_overdue(self):
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if self.due_back and date.today() > self.due_back:
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return True
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return False
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LOAN_STATUS = (
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('d', 'Maintenance'),
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('o', 'On loan'),
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('a', 'Available'),
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('r', 'Reserved'),
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)
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status= models.CharField(max_length=1, choices=LOAN_STATUS, blank=True, default='d', help_text='Book availability')
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class Meta:
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ordering = ["due_back"]
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permissions = (("can_mark_returned", "Set book as returned"),)
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def __str__(self):
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"""
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String for representing the Model object.
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"""
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#return '%s (%s)' % (self.id,self.book.title)
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return '{0} ({1})'.format(self.id,self.book.title)
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class Author(models.Model):
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"""
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Model representing an author.
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"""
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first_name = models.CharField(max_length=100)
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last_name = models.CharField(max_length=100)
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date_of_birth = models.DateField(null=True, blank=True)
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date_of_death = models.DateField('died', null=True, blank=True)
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class Meta:
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ordering = ["last_name","first_name"]
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def get_absolute_url(self):
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"""
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Returns the url to access a particular author instance.
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"""
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return reverse('author-detail', args=[str(self.id)])
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def __str__(self):
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"""
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String for representing the Model object.
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"""
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return '{0}, {1}'.format(self.last_name,self.first_name)
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