6.4. ORM Update
.update().save().update_or_create().bulk_update().select_for_update()
6.4.1. Update
QuerySet.update()
Customer.objects.filter(firstname='Mark', lastname='Watney').update(is_verified=True)
6.4.2. Save
Model.save()
mark = Customer.objects.get(firstname='Mark', lastname='Watney')
mark.is_verified = True
mark.save()
6.4.3. Update or Create
QuerySet.update_or_create()
customers = [
('Mark', 'Watney'),
('Melissa', 'Lewis'),
('Rick', 'Martinez'),
('Alex', 'Vogel'),
('Beth', 'Johansson'),
('Chris', 'Beck'),
]
for firstname, lastname in customers:
customer, was_created = Customer.objects.update_or_create(
firstname=firstname,
lastname=lastname,
defaults={'is_verified': True},
)
if was_created:
print(f'Created: {customer}')
else:
print(f'Updated: {customer}')
In the above example, we have a list of users that we want
to add to the database. We use the update_or_create method
to add them. If the user already exists, we update the is_verified
field to True.
6.4.4. Bulk Update
QuerySet.bulk_update()
customers = [
Customer.objects.create(firstname='Mark', lastname='Watney'),
Customer.objects.create(firstname='Melissa', lastname='Lewis'),
]
customers[0].is_verified = True
customers[1].is_verified = False
Customer.objects.bulk_update(customers, ['is_verified'])
2
6.4.5. Select for Update
QuerySet.select_for_update()
Returns a queryset that will lock rows until the end of the
transaction, generating a SELECT ... FOR UPDATE SQL statement
on supported databases.
from django.db import transaction
customers = Customer.objects.select_for_update().filter(gender='male')
with transaction.atomic():
for customer in customers:
...
6.4.6. Assignments
# doctest: +SKIP_FILE
# %% About
# - Name: Database ORM Create
# - Difficulty: easy
# - Lines: 3
# - Minutes: 2
# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author
# %% English
# 0. Use `myproject.shop`
# 1. Using ORM get user:
# firstname: John, lastname: Doe
# 2. Update his firstname to Jane
# 3. Use `.save()` method
# %% Polish
# 0. Użyj `myproject.shop`
# 1. Używając ORM znajdź użytkownika:
# firstname: John, lastname: Doe
# 2. Zmień jego imię na Jane
# 3. Użyj metody `.save()`
# %% Hints
# - `.get()`
# - `.save()`
# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 10), \
'Python 3.10+ required'
>>> assert result is not Ellipsis, \
'Assign your result to variable `result`'
>>> john = Customer.objects.filter(firstname='John', lastname='Doe')
>>> jane = Customer.objects.filter(firstname='Jane', lastname='Doe')
>>> assert not john.exists()
>>> assert jane.exists()
>>> assert jane.delete()
>>> assert john.delete()
"""
# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`
# %% Imports
import os; os.environ['DJANGO_SETTINGS_MODULE'] = 'myproject.settings'
import django; django.setup()
from shop.models import Customer
# %% Types
result: Customer
# %% Data
Customer.objects.create(firstname='John', lastname='Doe')
# %% Result
result = ...
# doctest: +SKIP_FILE
# %% About
# - Name: Database ORM Create
# - Difficulty: easy
# - Lines: 1
# - Minutes: 2
# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author
# %% English
# 0. Use `myproject.shop`
# 1. Define variable `result` with result of ORM call for:
# Update `Customer` firstname: John, lastname: Doe
# Set firstname: Jane
# 2. Use `.update()` method
# %% Polish
# 0. Użyj `myproject.shop`
# 1. Zdefiniuj zmienną `result` z wynikiem zapytania ORM dla:
# Zaktualizuj `Customer` firstname: John, lastname: Doe
# Ustaw firstname: Jane
# 2. Użyj metody `.update()`
# %% Hints
# - `.filter()`
# - `.update()`
# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 10), \
'Python 3.10+ required'
>>> assert result is not Ellipsis, \
'Assign your result to variable `result`'
>>> assert type(result) is int, \
'Variable `result` has invalid type, should be int'
>>> result
1
>>> john = Customer.objects.filter(firstname='John', lastname='Doe')
>>> jane = Customer.objects.filter(firstname='Jane', lastname='Doe')
>>> assert not john.exists()
>>> assert jane.exists()
>>> assert jane.delete()
>>> assert john.delete()
"""
# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`
# %% Imports
import os; os.environ['DJANGO_SETTINGS_MODULE'] = 'myproject.settings'
import django; django.setup()
from shop.models import Customer
# %% Types
result: int
# %% Data
Customer.objects.create(firstname='John', lastname='Doe')
# %% Result
result = ...
# doctest: +SKIP_FILE
# %% About
# - Name: Database ORM Create
# - Difficulty: easy
# - Lines: 1
# - Minutes: 2
# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author
# %% English
# 0. Use `myproject.shop`
# 1. Define variable `result` with result of ORM call for:
# update or create `Customer`
# firstname: John, lastname: Doe
# 2. Use `.update_or_create()` method
# 3. Mind, that method returns a two element tuple
# but we need only a `Customer`
# %% Polish
# 0. Użyj `myproject.shop`
# 1. Zdefiniuj zmienną `result` z wynikiem zapytania ORM dla:
# zaktualizuj lub stwórz `Customer`
# firstname: John, lastname: Doe
# 2. Użyj metody `.update_or_create()`
# 3. Zwróć uwagę, że metoda zwraca dwu elementową tuplę
# a potrzebny jest tylko `Customer`
# %% Hints
# - `.update_or_create()`
# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 10), \
'Python 3.10+ required'
>>> assert result is not Ellipsis, \
'Assign your result to variable `result`'
>>> assert type(result) is Customer, \
'Variable `result` has invalid type, should be Customer'
>>> result
<Customer: John Doe>
>>> john = Customer.objects.filter(firstname='John', lastname='Doe')
>>> assert john.exists()
>>> assert john.delete()
"""
# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`
# %% Imports
import os; os.environ['DJANGO_SETTINGS_MODULE'] = 'myproject.settings'
import django; django.setup()
from shop.models import Customer
# %% Types
result: Customer
# %% Data
Customer.objects.create(firstname='John', lastname='Doe')
# %% Result
result = ...