4.3. Models Field Numeric

  • models.IntegerField - stores a 32-bit value, minimum -2,147,483,648 and maximum 2,147,483,647

  • models.FloatField - stores a 64-bit floating-point number, minimum -1.79E+308 and maximum 1.79E+308

  • models.DecimalField - stores a fixed-point number (e.g. a monetary amount), requires two arguments: max_digits and decimal_places

  • models.SmallIntegerField - stores a 16-bit value, minimum -32,768 and maximum 32,767

  • models.BigIntegerField - stores a 64-bit value, minimum -9,223,372,036,854,775,808 and maximum 9,223,372,036,854,775,807

  • models.PositiveSmallIntegerField - stores a positive 16-bit value (unsigned int16), minimum 0 and maximum 65,535

  • models.PositiveIntegerField - stores a positive 32-bit value (unsigned int32), minimum 0 and maximum 4,294,967,295

  • models.PositiveBigIntegerField - stores a positive 64-bit value (unsigned int64), minimum 0 and maximum 18,446,744,073,709,551,615

  • models.AutoField - stores an IntegerField that automatically increments according to available IDs

  • models.BigAutoField - stores a 64-bit integer, much like an AutoField except that it is guaranteed to fit numbers from -9223372036854775808 to 9223372036854775807

  • models.SmallAutoField - like an `AutoField, but only allows values under a certain (database-dependent) point

  • float vs. decimal (IEEE-754)

4.3.1. SetUp

>>> from django.core.validators import MinValueValidator, MaxValueValidator
>>> from django.db import models
>>> from django.utils.translation import gettext_lazy as _

4.3.2. Arguments

  • decimal_places (DecimalField)

  • max_digits (DecimalField)

  • blank

  • choices

  • db_column

  • db_index

  • default

  • editable

  • error_message

  • help_text

  • limit_choices_to

  • max_length

  • null

  • primary_key

  • unique

  • validators

  • verbose_name

4.3.3. IntegerField

  • IntegerField

  • SmallIntegerField

  • BigIntegerField

>>> height = models.IntegerField(
...     verbose_name=_('Height'),
...     help_text=_('cm'),
...     null=True,
...     blank=True,
...     default=None,
... )

4.3.4. PositiveIntegerField

  • PositiveIntegerField

  • PositiveSmallIntegerField

  • PositiveBigIntegerField

4.3.5. FloatField

  • FloatField

>>> weight = models.FloatField(
...     verbose_name=_('Weight'),
...     help_text=_('kg'),
...     null=True,
...     blank=True,
...     default=None,
... )

4.3.6. DecimalField

  • DecimalField

>>> salary = models.DecimalField(
...     verbose_name=_('Salary'),
...     help_text=_('USD per year'),
...     max_digits=12,
...     decimal_places=2,
...     null=True,
...     blank=True,
...     default=None,
... )

4.3.7. AutoField

  • AutoField

  • BigAutoField

  • SmallAutoField

4.3.8. Validators

  • MinLengthValidator

  • MaxLengthValidator

>>> height = models.IntegerField(
...     verbose_name=_('Height'),
...     help_text=_('cm'),
...     validators=[MinValueValidator(150), MaxValueValidator(220)],
...     null=True,
...     blank=True,
...     default=None,
... )

>>> weight = models.FloatField(
...     verbose_name=_('Weight'),
...     help_text=_('kg'),
...     validators=[MinValueValidator(50), MaxValueValidator(150)],
...     null=True,
...     blank=True,
...     default=None,
... )

>>> salary = models.DecimalField(
...     verbose_name=_('Salary'),
...     help_text=_('USD per year'),
...     validators=[MinValueValidator(0.0), MaxValueValidator(999_999.99)],
...     max_digits=12,
...     decimal_places=2,
...     null=True,
...     blank=True,
...     default=None,
... )

4.3.9. Use Case - 1

>>> 
... from django.core.validators import MinValueValidator, MaxValueValidator
... from django.db import models
... from django.utils.translation import gettext_lazy as _
...
...
... class Customer(models.Model):
...     firstname = models.CharField(verbose_name=_('First Name'), max_length=100, null=False, blank=False)
...     lastname = models.CharField(verbose_name=_('Last Name'), max_length=100, null=False, blank=False, db_index=True)
...     height = models.PositiveSmallIntegerField(verbose_name=_('Height'), help_text=_('cm'), null=True, blank=True, default=None, validators=[MinValueValidator(0), MaxValueValidator(250)])
...     weight = models.FloatField(verbose_name=_('Weight'), help_text=_('kg'), null=True, blank=True, default=None, validators=[MinValueValidator(0), MaxValueValidator(300)])
...     salary = models.DecimalField(verbose_name=_('Salary'), help_text=_('USD per month'), blank=True, null=True, default=None, max_digits=6, decimal_places=2, validators=[MinValueValidator(0), MaxValueValidator(10_000)])
...
...     class Meta:
...         verbose_name = _('Customer')
...         verbose_name_plural = _('Customer')
...
...    def __str__(self):
...         return f'{self.firstname} {self.lastname}'

4.3.10. Assignments

# TODO: Create Tests
# doctest: +SKIP_FILE
# %% 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

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Django Model Numeric
# - Difficulty: easy
# - Lines: 1
# - Minutes: 3

# %% English
# 0. Use `myproject.demo`
# 1. Alter model `Person`
# 2. Add field `height` as `models.IntegerField`:
#    - verbose_name=_('Height')
#    - help_text=_('cm')
#    - validator=[MinValueValidator(150), MaxValueValidator(250)]
#    - null=True
#    - blank=True
#    - default=None
# 3. Use `gettext_lazy`
# 4. Run `makemigrations`
# 5. Run `migrate`

# %% Polish
# 0. Użyj `myproject.demo`
# 1. Zmień model `Person`
# 2. Dodaj pole `height` jako `models.IntegerField`:
#    - verbose_name=_('Height')
#    - help_text=_('cm')
#    - validator=[MinValueValidator(150), MaxValueValidator(250)]
#    - null=True
#    - blank=True
#    - default=None
# 3. Użyj `gettext_lazy`
# 4. Uruchom `makemigrations`
# 5. Uruchom `migrate`

# %% Output
# - `Add field height to person`
# - `Applying demo.0007_person_height... OK`

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 10), \
'Python 3.10+ required'
"""

from django.core.validators import MinValueValidator, MaxValueValidator
from django.db import models
from django.utils.translation import gettext_lazy as _


class Person(models.Model):
    height = ...


# TODO: Create Tests
# doctest: +SKIP_FILE
# %% 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

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Django Model Numeric
# - Difficulty: easy
# - Lines: 1
# - Minutes: 3

# %% English
# 0. Use `myproject.demo`
# 1. Alter model `Person`
# 2. Add field `weight` as `models.FloatField`:
#    - verbose_name=_('Weight')
#    - help_text=_('kg')
#    - validator=[MinValueValidator(50), MaxValueValidator(150)]
#    - null=True
#    - blank=True
#    - default=None
# 3. Use `gettext_lazy`
# 4. Run `makemigrations`
# 5. Run `migrate`

# %% Polish
# 0. Użyj `myproject.demo`
# 1. Zmień model `Person`
# 2. Dodaj pole `weight` jako `models.FloatField`:
#    - verbose_name=_('Weight')
#    - help_text=_('kg')
#    - validator=[MinValueValidator(50), MaxValueValidator(150)]
#    - null=True
#    - blank=True
#    - default=None
# 3. Użyj `gettext_lazy`
# 4. Uruchom `makemigrations`
# 5. Uruchom `migrate`

# %% Output
# - `Add field weight to person`
# - `Applying demo.0007_person_weight... OK`

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 10), \
'Python 3.10+ required'
"""

from django.core.validators import MinValueValidator, MaxValueValidator
from django.db import models
from django.utils.translation import gettext_lazy as _


class Person(models.Model):
    weight = ...


# TODO: Create Tests
# doctest: +SKIP_FILE
# %% 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

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Django Model Numeric
# - Difficulty: easy
# - Lines: 1
# - Minutes: 3

# %% English
# 0. Use `myproject.demo`
# 1. Alter model `Person`
# 2. Add field `salary` as `models.DecimalField`:
#    - verbose_name=_('Salary')
#    - help_text=_('USD per year')
#    - validators=[MinValueValidator(0.0), MaxValueValidator(999_999.99)]
#    - max_digits=12
#    - decimal_places=2
#    - null=True
#    - blank=True
#    - default=None
# 3. Use `gettext_lazy`
# 4. Run `makemigrations`
# 5. Run `migrate`

# %% Polish
# 0. Użyj `myproject.demo`
# 1. Zmień model `Person`
# 2. Dodaj pole `salary` jako `models.DecimalField`:
#    - verbose_name=_('Salary')
#    - help_text=_('USD per year')
#    - validators=[MinValueValidator(0.0), MaxValueValidator(999_999.99)]
#    - max_digits=12
#    - decimal_places=2
#    - null=True
#    - blank=True
#    - default=None
# 3. Użyj `gettext_lazy`
# 4. Uruchom `makemigrations`
# 5. Uruchom `migrate`

# %% Output
# - `Add field salary to person`
# - `Applying demo.0007_person_salary... OK`

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 10), \
'Python 3.10+ required'
"""

from django.core.validators import MinValueValidator, MaxValueValidator
from django.db import models
from django.utils.translation import gettext_lazy as _


class Person(models.Model):
    salary = ...