Code-Memo

Model Fields

Common Model Fields

CharField

• Usage: Stores a fixed-length string.
• Example:

  class Person(models.Model):
      name = models.CharField(max_length=100)
  

TextField

• Usage: Stores large amounts of text.
• Example:

  class Article(models.Model):
      content = models.TextField()
  

IntegerField, FloatField, DecimalField

• Usage: Stores numeric data.
• Examples:

  class Product(models.Model):
      quantity = models.IntegerField()
      price = models.DecimalField(max_digits=10, decimal_places=2)  # Precise price storage
      rating = models.FloatField()
  

• FloatField is a Django model field used to store floating-point numbers. It’s a wrapper around Python’s float type.
• If precision is crucial (e.g., for money calculations), you should use DecimalField.
• Django automatically uses Python’s Decimal type from the decimal module for storing and handling values. Example on Decimal type:

  from decimal import Decimal
  n = Decimal('0.1')
  print(n)
  

BooleanField

• Usage: Stores boolean (True/False) values.
• Example:

  class Task(models.Model):
      completed = models.BooleanField(default=False)
  

DateField, DateTimeField

• Usage: Stores dates and date-time information.
• Examples:

  class Event(models.Model):
      event_date = models.DateField()
      event_datetime = models.DateTimeField(auto_now_add=True)
  

Note: auto_now_add automatically adds the date. If you want to change the timezone used by Django’s auto_now_add feature from UTC to another timezone, you need to configure Django’s timezone settings appropriately in your settings file (settings.py):

1. Set Timezone in settings.py: Ensure your desired timezone is set in your Django project settings:

   TIME_ZONE = 'America/New_York'
   

2. Enable Timezone Support: Ensure that Django’s timezone support is enabled by setting USE_TZ to True in your settings.py file:

   USE_TZ = True
   

FileField, ImageField

• Usage: Handles file and image uploads.
• Example:

  class Document(models.Model):
      doc_file = models.FileField(upload_to='documents/')
      image_file = models.ImageField(upload_to='images/')
  

  • doc_file stores uploaded documents.
  • image_file stores uploaded images.

AutoField, BigAutoField

• Usage: Auto incremented field.
• Example:

  class Document(models.Model):
      id = models.BigAutoField(primary_key=True)
  

BigIntegerField

• Usage: BigInt field.
• Example:

  class Document(models.Model):
      id = models.BigIntegerField(primary_key=True)
  

ForeignKey, OneToOneField, ManyToManyField

• Usage: Defines relationships between models.

• Examples:

  class Author(models.Model):
      name = models.CharField(max_length=100)
  
  class Book(models.Model):
      title = models.CharField(max_length=100)
      author = models.ForeignKey(Author, on_delete=models.CASCADE)