840 lines
26 KiB
Plaintext
840 lines
26 KiB
Plaintext
PostgreSQL specific model fields
|
|
================================
|
|
|
|
All of these fields are available from the ``django.contrib.postgres.fields``
|
|
module.
|
|
|
|
.. currentmodule:: django.contrib.postgres.fields
|
|
|
|
ArrayField
|
|
----------
|
|
|
|
.. class:: ArrayField(base_field, size=None, **options)
|
|
|
|
A field for storing lists of data. Most field types can be used, you simply
|
|
pass another field instance as the :attr:`base_field
|
|
<ArrayField.base_field>`. You may also specify a :attr:`size
|
|
<ArrayField.size>`. ``ArrayField`` can be nested to store multi-dimensional
|
|
arrays.
|
|
|
|
.. attribute:: base_field
|
|
|
|
This is a required argument.
|
|
|
|
Specifies the underlying data type and behavior for the array. It
|
|
should be an instance of a subclass of
|
|
:class:`~django.db.models.Field`. For example, it could be an
|
|
:class:`~django.db.models.IntegerField` or a
|
|
:class:`~django.db.models.CharField`. Most field types are permitted,
|
|
with the exception of those handling relational data
|
|
(:class:`~django.db.models.ForeignKey`,
|
|
:class:`~django.db.models.OneToOneField` and
|
|
:class:`~django.db.models.ManyToManyField`).
|
|
|
|
It is possible to nest array fields - you can specify an instance of
|
|
``ArrayField`` as the ``base_field``. For example::
|
|
|
|
from django.db import models
|
|
from django.contrib.postgres.fields import ArrayField
|
|
|
|
class ChessBoard(models.Model):
|
|
board = ArrayField(
|
|
ArrayField(
|
|
models.CharField(max_length=10, blank=True),
|
|
size=8,
|
|
),
|
|
size=8,
|
|
)
|
|
|
|
Transformation of values between the database and the model, validation
|
|
of data and configuration, and serialization are all delegated to the
|
|
underlying base field.
|
|
|
|
.. attribute:: size
|
|
|
|
This is an optional argument.
|
|
|
|
If passed, the array will have a maximum size as specified. This will
|
|
be passed to the database, although PostgreSQL at present does not
|
|
enforce the restriction.
|
|
|
|
.. note::
|
|
|
|
When nesting ``ArrayField``, whether you use the `size` parameter or not,
|
|
PostgreSQL requires that the arrays are rectangular::
|
|
|
|
from django.contrib.postgres.fields import ArrayField
|
|
from django.db import models
|
|
|
|
class Board(models.Model):
|
|
pieces = ArrayField(ArrayField(models.IntegerField()))
|
|
|
|
# Valid
|
|
Board(pieces=[
|
|
[2, 3],
|
|
[2, 1],
|
|
])
|
|
|
|
# Not valid
|
|
Board(pieces=[
|
|
[2, 3],
|
|
[2],
|
|
])
|
|
|
|
If irregular shapes are required, then the underlying field should be made
|
|
nullable and the values padded with ``None``.
|
|
|
|
Querying ArrayField
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
There are a number of custom lookups and transforms for :class:`ArrayField`.
|
|
We will use the following example model::
|
|
|
|
from django.db import models
|
|
from django.contrib.postgres.fields import ArrayField
|
|
|
|
class Post(models.Model):
|
|
name = models.CharField(max_length=200)
|
|
tags = ArrayField(models.CharField(max_length=200), blank=True)
|
|
|
|
def __str__(self): # __unicode__ on Python 2
|
|
return self.name
|
|
|
|
.. fieldlookup:: arrayfield.contains
|
|
|
|
contains
|
|
~~~~~~~~
|
|
|
|
The :lookup:`contains` lookup is overridden on :class:`ArrayField`. The
|
|
returned objects will be those where the values passed are a subset of the
|
|
data. It uses the SQL operator ``@>``. For example::
|
|
|
|
>>> Post.objects.create(name='First post', tags=['thoughts', 'django'])
|
|
>>> Post.objects.create(name='Second post', tags=['thoughts'])
|
|
>>> Post.objects.create(name='Third post', tags=['tutorial', 'django'])
|
|
|
|
>>> Post.objects.filter(tags__contains=['thoughts'])
|
|
[<Post: First post>, <Post: Second post>]
|
|
|
|
>>> Post.objects.filter(tags__contains=['django'])
|
|
[<Post: First post>, <Post: Third post>]
|
|
|
|
>>> Post.objects.filter(tags__contains=['django', 'thoughts'])
|
|
[<Post: First post>]
|
|
|
|
.. fieldlookup:: arrayfield.contained_by
|
|
|
|
contained_by
|
|
~~~~~~~~~~~~
|
|
|
|
This is the inverse of the :lookup:`contains <arrayfield.contains>` lookup -
|
|
the objects returned will be those where the data is a subset of the values
|
|
passed. It uses the SQL operator ``<@``. For example::
|
|
|
|
>>> Post.objects.create(name='First post', tags=['thoughts', 'django'])
|
|
>>> Post.objects.create(name='Second post', tags=['thoughts'])
|
|
>>> Post.objects.create(name='Third post', tags=['tutorial', 'django'])
|
|
|
|
>>> Post.objects.filter(tags__contained_by=['thoughts', 'django'])
|
|
[<Post: First post>, <Post: Second post>]
|
|
|
|
>>> Post.objects.filter(tags__contained_by=['thoughts', 'django', 'tutorial'])
|
|
[<Post: First post>, <Post: Second post>, <Post: Third post>]
|
|
|
|
.. fieldlookup:: arrayfield.overlap
|
|
|
|
overlap
|
|
~~~~~~~
|
|
|
|
Returns objects where the data shares any results with the values passed. Uses
|
|
the SQL operator ``&&``. For example::
|
|
|
|
>>> Post.objects.create(name='First post', tags=['thoughts', 'django'])
|
|
>>> Post.objects.create(name='Second post', tags=['thoughts'])
|
|
>>> Post.objects.create(name='Third post', tags=['tutorial', 'django'])
|
|
|
|
>>> Post.objects.filter(tags__overlap=['thoughts'])
|
|
[<Post: First post>, <Post: Second post>]
|
|
|
|
>>> Post.objects.filter(tags__overlap=['thoughts', 'tutorial'])
|
|
[<Post: First post>, <Post: Second post>, <Post: Third post>]
|
|
|
|
.. fieldlookup:: arrayfield.len
|
|
|
|
len
|
|
~~~
|
|
|
|
Returns the length of the array. The lookups available afterwards are those
|
|
available for :class:`~django.db.models.IntegerField`. For example::
|
|
|
|
>>> Post.objects.create(name='First post', tags=['thoughts', 'django'])
|
|
>>> Post.objects.create(name='Second post', tags=['thoughts'])
|
|
|
|
>>> Post.objects.filter(tags__len=1)
|
|
[<Post: Second post>]
|
|
|
|
.. fieldlookup:: arrayfield.index
|
|
|
|
Index transforms
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
This class of transforms allows you to index into the array in queries. Any
|
|
non-negative integer can be used. There are no errors if it exceeds the
|
|
:attr:`size <ArrayField.size>` of the array. The lookups available after the
|
|
transform are those from the :attr:`base_field <ArrayField.base_field>`. For
|
|
example::
|
|
|
|
>>> Post.objects.create(name='First post', tags=['thoughts', 'django'])
|
|
>>> Post.objects.create(name='Second post', tags=['thoughts'])
|
|
|
|
>>> Post.objects.filter(tags__0='thoughts')
|
|
[<Post: First post>, <Post: Second post>]
|
|
|
|
>>> Post.objects.filter(tags__1__iexact='Django')
|
|
[<Post: First post>]
|
|
|
|
>>> Post.objects.filter(tags__276='javascript')
|
|
[]
|
|
|
|
.. note::
|
|
|
|
PostgreSQL uses 1-based indexing for array fields when writing raw SQL.
|
|
However these indexes and those used in :lookup:`slices <arrayfield.slice>`
|
|
use 0-based indexing to be consistent with Python.
|
|
|
|
.. fieldlookup:: arrayfield.slice
|
|
|
|
Slice transforms
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
This class of transforms allow you to take a slice of the array. Any two
|
|
non-negative integers can be used, separated by a single underscore. The
|
|
lookups available after the transform do not change. For example::
|
|
|
|
>>> Post.objects.create(name='First post', tags=['thoughts', 'django'])
|
|
>>> Post.objects.create(name='Second post', tags=['thoughts'])
|
|
>>> Post.objects.create(name='Third post', tags=['django', 'python', 'thoughts'])
|
|
|
|
>>> Post.objects.filter(tags__0_1=['thoughts'])
|
|
[<Post: First post>]
|
|
|
|
>>> Post.objects.filter(tags__0_2__contains='thoughts')
|
|
[<Post: First post>, <Post: Second post>]
|
|
|
|
.. note::
|
|
|
|
PostgreSQL uses 1-based indexing for array fields when writing raw SQL.
|
|
However these slices and those used in :lookup:`indexes <arrayfield.index>`
|
|
use 0-based indexing to be consistent with Python.
|
|
|
|
.. admonition:: Multidimensional arrays with indexes and slices
|
|
|
|
PostgreSQL has some rather esoteric behavior when using indexes and slices
|
|
on multidimensional arrays. It will always work to use indexes to reach
|
|
down to the final underlying data, but most other slices behave strangely
|
|
at the database level and cannot be supported in a logical, consistent
|
|
fashion by Django.
|
|
|
|
Indexing ArrayField
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
At present using :attr:`~django.db.models.Field.db_index` will create a
|
|
``btree`` index. This does not offer particularly significant help to querying.
|
|
A more useful index is a ``GIN`` index, which you should create using a
|
|
:class:`~django.db.migrations.operations.RunSQL` operation.
|
|
|
|
HStoreField
|
|
-----------
|
|
|
|
.. class:: HStoreField(**options)
|
|
|
|
A field for storing mappings of strings to strings. The Python data type
|
|
used is a ``dict``.
|
|
|
|
To use this field, you'll need to:
|
|
|
|
1. Add ``'django.contrib.postgres'`` in your :setting:`INSTALLED_APPS`.
|
|
2. Setup the hstore extension in PostgreSQL before the first ``CreateModel``
|
|
or ``AddField`` operation by adding a migration with the
|
|
:class:`~django.contrib.postgres.operations.HStoreExtension` operation.
|
|
For example::
|
|
|
|
from django.contrib.postgres.operations import HStoreExtension
|
|
|
|
class Migration(migrations.Migration):
|
|
...
|
|
|
|
operations = [
|
|
HStoreExtension(),
|
|
...
|
|
]
|
|
|
|
Creating the extension requires a database user with superuser
|
|
privileges. If the Django database user doesn't have superuser
|
|
privileges, you'll have to create the extension outside of Django
|
|
migrations with a user that has the appropriate privileges. In that
|
|
case, connect to your Django database and run the query
|
|
``CREATE EXTENSION IF NOT EXISTS hstore;``
|
|
|
|
You'll see an error like ``can't adapt type 'dict'`` if you skip the first
|
|
step, or ``type "hstore" does not exist`` if you skip the second.
|
|
|
|
.. note::
|
|
|
|
On occasions it may be useful to require or restrict the keys which are
|
|
valid for a given field. This can be done using the
|
|
:class:`~django.contrib.postgres.validators.KeysValidator`.
|
|
|
|
Querying HStoreField
|
|
^^^^^^^^^^^^^^^^^^^^
|
|
|
|
In addition to the ability to query by key, there are a number of custom
|
|
lookups available for ``HStoreField``.
|
|
|
|
We will use the following example model::
|
|
|
|
from django.contrib.postgres.fields import HStoreField
|
|
from django.db import models
|
|
|
|
class Dog(models.Model):
|
|
name = models.CharField(max_length=200)
|
|
data = HStoreField()
|
|
|
|
def __str__(self): # __unicode__ on Python 2
|
|
return self.name
|
|
|
|
.. fieldlookup:: hstorefield.key
|
|
|
|
Key lookups
|
|
~~~~~~~~~~~
|
|
|
|
To query based on a given key, you simply use that key as the lookup name::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={'breed': 'labrador'})
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie'})
|
|
|
|
>>> Dog.objects.filter(data__breed='collie')
|
|
[<Dog: Meg>]
|
|
|
|
You can chain other lookups after key lookups::
|
|
|
|
>>> Dog.objects.filter(data__breed__contains='l')
|
|
[<Dog: Rufus>, <Dog: Meg>]
|
|
|
|
If the key you wish to query by clashes with the name of another lookup, you
|
|
need to use the :lookup:`hstorefield.contains` lookup instead.
|
|
|
|
.. warning::
|
|
|
|
Since any string could be a key in a hstore value, any lookup other than
|
|
those listed below will be interpreted as a key lookup. No errors are
|
|
raised. Be extra careful for typing mistakes, and always check your queries
|
|
work as you intend.
|
|
|
|
.. fieldlookup:: hstorefield.contains
|
|
|
|
contains
|
|
~~~~~~~~
|
|
|
|
The :lookup:`contains` lookup is overridden on
|
|
:class:`~django.contrib.postgres.fields.HStoreField`. The returned objects are
|
|
those where the given ``dict`` of key-value pairs are all contained in the
|
|
field. It uses the SQL operator ``@>``. For example::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={'breed': 'labrador', 'owner': 'Bob'})
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': 'Bob'})
|
|
>>> Dog.objects.create(name='Fred', data={})
|
|
|
|
>>> Dog.objects.filter(data__contains={'owner': 'Bob'})
|
|
[<Dog: Rufus>, <Dog: Meg>]
|
|
|
|
>>> Dog.objects.filter(data__contains={'breed': 'collie'})
|
|
[<Dog: Meg>]
|
|
|
|
.. fieldlookup:: hstorefield.contained_by
|
|
|
|
contained_by
|
|
~~~~~~~~~~~~
|
|
|
|
This is the inverse of the :lookup:`contains <hstorefield.contains>` lookup -
|
|
the objects returned will be those where the key-value pairs on the object are
|
|
a subset of those in the value passed. It uses the SQL operator ``<@``. For
|
|
example::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={'breed': 'labrador', 'owner': 'Bob'})
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': 'Bob'})
|
|
>>> Dog.objects.create(name='Fred', data={})
|
|
|
|
>>> Dog.objects.filter(data__contained_by={'breed': 'collie', 'owner': 'Bob'})
|
|
[<Dog: Meg>, <Dog: Fred>]
|
|
|
|
>>> Dog.objects.filter(data__contained_by={'breed': 'collie'})
|
|
[<Dog: Fred>]
|
|
|
|
.. fieldlookup:: hstorefield.has_key
|
|
|
|
has_key
|
|
~~~~~~~
|
|
|
|
Returns objects where the given key is in the data. Uses the SQL operator
|
|
``?``. For example::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={'breed': 'labrador'})
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': 'Bob'})
|
|
|
|
>>> Dog.objects.filter(data__has_key='owner')
|
|
[<Dog: Meg>]
|
|
|
|
.. fieldlookup:: hstorefield.has_any_keys
|
|
|
|
has_any_keys
|
|
~~~~~~~~~~~~
|
|
|
|
.. versionadded:: 1.9
|
|
|
|
Returns objects where any of the given keys are in the data. Uses the SQL
|
|
operator ``?|``. For example::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={'breed': 'labrador'})
|
|
>>> Dog.objects.create(name='Meg', data={'owner': 'Bob'})
|
|
>>> Dog.objects.create(name='Fred', data={})
|
|
|
|
>>> Dog.objects.filter(data__has_any_keys=['owner', 'breed'])
|
|
[<Dog: Rufus>, <Dog: Meg>]
|
|
|
|
.. fieldlookup:: hstorefield.has_keys
|
|
|
|
has_keys
|
|
~~~~~~~~
|
|
|
|
Returns objects where all of the given keys are in the data. Uses the SQL operator
|
|
``?&``. For example::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={})
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': 'Bob'})
|
|
|
|
>>> Dog.objects.filter(data__has_keys=['breed', 'owner'])
|
|
[<Dog: Meg>]
|
|
|
|
.. fieldlookup:: hstorefield.keys
|
|
|
|
keys
|
|
~~~~
|
|
|
|
Returns objects where the array of keys is the given value. Note that the order
|
|
is not guaranteed to be reliable, so this transform is mainly useful for using
|
|
in conjunction with lookups on
|
|
:class:`~django.contrib.postgres.fields.ArrayField`. Uses the SQL function
|
|
``akeys()``. For example::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={'toy': 'bone'})
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': 'Bob'})
|
|
|
|
>>> Dog.objects.filter(data__keys__overlap=['breed', 'toy'])
|
|
[<Dog: Rufus>, <Dog: Meg>]
|
|
|
|
.. fieldlookup:: hstorefield.values
|
|
|
|
values
|
|
~~~~~~
|
|
|
|
Returns objects where the array of values is the given value. Note that the
|
|
order is not guaranteed to be reliable, so this transform is mainly useful for
|
|
using in conjunction with lookups on
|
|
:class:`~django.contrib.postgres.fields.ArrayField`. Uses the SQL function
|
|
``avalues()``. For example::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={'breed': 'labrador'})
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie', 'owner': 'Bob'})
|
|
|
|
>>> Dog.objects.filter(data__values__contains=['collie'])
|
|
[<Dog: Meg>]
|
|
|
|
JSONField
|
|
---------
|
|
|
|
.. versionadded:: 1.9
|
|
|
|
.. class:: JSONField(**options)
|
|
|
|
A field for storing JSON encoded data. In Python the data is represented in
|
|
its Python native format: dictionaries, lists, strings, numbers, booleans
|
|
and ``None``.
|
|
|
|
.. note::
|
|
|
|
PostgreSQL has two native JSON based data types: ``json`` and ``jsonb``.
|
|
The main difference between them is how they are stored and how they can be
|
|
queried. PostgreSQL's ``json`` field is stored as the original string
|
|
representation of the JSON and must be decoded on the fly when queried
|
|
based on keys. The ``jsonb`` field is stored based on the actual structure
|
|
of the JSON which allows indexing. The trade-off is a small additional cost
|
|
on writing to the ``jsonb`` field. ``JSONField`` uses ``jsonb``.
|
|
|
|
**As a result, the usage of this field is only supported on PostgreSQL
|
|
versions at least 9.4**.
|
|
|
|
Querying JSONField
|
|
^^^^^^^^^^^^^^^^^^
|
|
|
|
We will use the following example model::
|
|
|
|
from django.contrib.postgres.fields import JSONField
|
|
from django.db import models
|
|
|
|
class Dog(models.Model):
|
|
name = models.CharField(max_length=200)
|
|
data = JSONField()
|
|
|
|
def __str__(self): # __unicode__ on Python 2
|
|
return self.name
|
|
|
|
.. fieldlookup:: jsonfield.key
|
|
|
|
Key, index, and path lookups
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
To query based on a given dictionary key, simply use that key as the lookup
|
|
name::
|
|
|
|
>>> Dog.objects.create(name='Rufus', data={
|
|
... 'breed': 'labrador',
|
|
... 'owner': {
|
|
... 'name': 'Bob',
|
|
... 'other_pets': [{
|
|
... 'name': 'Fishy',
|
|
... }],
|
|
... },
|
|
... })
|
|
>>> Dog.objects.create(name='Meg', data={'breed': 'collie'})
|
|
|
|
>>> Dog.objects.filter(data__breed='collie')
|
|
[<Dog: Meg>]
|
|
|
|
Multiple keys can be chained together to form a path lookup::
|
|
|
|
>>> Dog.objects.filter(data__owner__name='Bob')
|
|
[<Dog: Rufus>]
|
|
|
|
If the key is an integer, it will be interpreted as an index lookup in an
|
|
array::
|
|
|
|
>>> Dog.objects.filter(data__owner__other_pets__0__name='Fishy')
|
|
[<Dog: Rufus>]
|
|
|
|
If the key you wish to query by clashes with the name of another lookup, use
|
|
the :lookup:`jsonfield.contains` lookup instead.
|
|
|
|
If only one key or index is used, the SQL operator ``->`` is used. If multiple
|
|
operators are used then the ``#>`` operator is used.
|
|
|
|
.. warning::
|
|
|
|
Since any string could be a key in a JSON object, any lookup other than
|
|
those listed below will be interpreted as a key lookup. No errors are
|
|
raised. Be extra careful for typing mistakes, and always check your queries
|
|
work as you intend.
|
|
|
|
Containment and key operations
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. fieldlookup:: jsonfield.contains
|
|
.. fieldlookup:: jsonfield.contained_by
|
|
.. fieldlookup:: jsonfield.has_key
|
|
.. fieldlookup:: jsonfield.has_any_keys
|
|
.. fieldlookup:: jsonfield.has_keys
|
|
|
|
:class:`~django.contrib.postgres.fields.JSONField` shares lookups relating to
|
|
containment and keys with :class:`~django.contrib.postgres.fields.HStoreField`.
|
|
|
|
- :lookup:`contains <hstorefield.contains>` (accepts any JSON rather than
|
|
just a dictionary of strings)
|
|
- :lookup:`contained_by <hstorefield.contained_by>` (accepts any JSON
|
|
rather than just a dictionary of strings)
|
|
- :lookup:`has_key <hstorefield.has_key>`
|
|
- :lookup:`has_any_keys <hstorefield.has_any_keys>`
|
|
- :lookup:`has_keys <hstorefield.has_keys>`
|
|
|
|
.. _range-fields:
|
|
|
|
Range Fields
|
|
------------
|
|
|
|
There are five range field types, corresponding to the built-in range types in
|
|
PostgreSQL. These fields are used to store a range of values; for example the
|
|
start and end timestamps of an event, or the range of ages an activity is
|
|
suitable for.
|
|
|
|
All of the range fields translate to :ref:`psycopg2 Range objects
|
|
<psycopg2:adapt-range>` in python, but also accept tuples as input if no bounds
|
|
information is necessary. The default is lower bound included, upper bound
|
|
excluded.
|
|
|
|
IntegerRangeField
|
|
^^^^^^^^^^^^^^^^^
|
|
|
|
.. class:: IntegerRangeField(**options)
|
|
|
|
Stores a range of integers. Based on an
|
|
:class:`~django.db.models.IntegerField`. Represented by an ``int4range`` in
|
|
the database and a :class:`~psycopg2:psycopg2.extras.NumericRange` in
|
|
Python.
|
|
|
|
BigIntegerRangeField
|
|
^^^^^^^^^^^^^^^^^^^^
|
|
|
|
.. class:: BigIntegerRangeField(**options)
|
|
|
|
Stores a range of large integers. Based on a
|
|
:class:`~django.db.models.BigIntegerField`. Represented by an ``int8range``
|
|
in the database and a :class:`~psycopg2:psycopg2.extras.NumericRange` in
|
|
Python.
|
|
|
|
FloatRangeField
|
|
^^^^^^^^^^^^^^^
|
|
|
|
.. class:: FloatRangeField(**options)
|
|
|
|
Stores a range of floating point values. Based on a
|
|
:class:`~django.db.models.FloatField`. Represented by a ``numrange`` in the
|
|
database and a :class:`~psycopg2:psycopg2.extras.NumericRange` in Python.
|
|
|
|
DateTimeRangeField
|
|
^^^^^^^^^^^^^^^^^^
|
|
|
|
.. class:: DateTimeRangeField(**options)
|
|
|
|
Stores a range of timestamps. Based on a
|
|
:class:`~django.db.models.DateTimeField`. Represented by a ``tztsrange`` in
|
|
the database and a :class:`~psycopg2:psycopg2.extras.DateTimeTZRange` in
|
|
Python.
|
|
|
|
DateRangeField
|
|
^^^^^^^^^^^^^^
|
|
|
|
.. class:: DateRangeField(**options)
|
|
|
|
Stores a range of dates. Based on a
|
|
:class:`~django.db.models.DateField`. Represented by a ``daterange`` in the
|
|
database and a :class:`~psycopg2:psycopg2.extras.DateRange` in Python.
|
|
|
|
Querying Range Fields
|
|
^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
There are a number of custom lookups and transforms for range fields. They are
|
|
available on all the above fields, but we will use the following example
|
|
model::
|
|
|
|
from django.contrib.postgres.fields import IntegerRangeField
|
|
from django.db import models
|
|
|
|
class Event(models.Model):
|
|
name = models.CharField(max_length=200)
|
|
ages = IntegerRangeField()
|
|
start = models.DateTimeField()
|
|
|
|
def __str__(self): # __unicode__ on Python 2
|
|
return self.name
|
|
|
|
We will also use the following example objects::
|
|
|
|
>>> import datetime
|
|
>>> from django.utils import timezone
|
|
>>> now = timezone.now()
|
|
>>> Event.objects.create(name='Soft play', ages=(0, 10), start=now)
|
|
>>> Event.objects.create(name='Pub trip', ages=(21, None), start=now - datetime.timedelta(days=1))
|
|
|
|
and ``NumericRange``:
|
|
|
|
>>> from psycopg2.extras import NumericRange
|
|
|
|
Containment functions
|
|
~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
As with other PostgreSQL fields, there are three standard containment
|
|
operators: ``contains``, ``contained_by`` and ``overlap``, using the SQL
|
|
operators ``@>``, ``<@``, and ``&&`` respectively.
|
|
|
|
.. fieldlookup:: rangefield.contains
|
|
|
|
contains
|
|
''''''''
|
|
|
|
>>> Event.objects.filter(ages__contains=NumericRange(4, 5))
|
|
[<Event: Soft play>]
|
|
|
|
.. fieldlookup:: rangefield.contained_by
|
|
|
|
contained_by
|
|
''''''''''''
|
|
|
|
>>> Event.objects.filter(ages__contained_by=NumericRange(0, 15))
|
|
[<Event: Soft play>]
|
|
|
|
.. versionadded 1.9
|
|
|
|
The `contained_by` lookup is also available on the non-range field types:
|
|
:class:`~django.db.models.fields.IntegerField`,
|
|
:class:`~django.db.models.fields.BigIntegerField`,
|
|
:class:`~django.db.models.fields.FloatField`,
|
|
:class:`~django.db.models.fields.DateField`, and
|
|
:class:`~django.db.models.fields.DateTimeField`. For example::
|
|
|
|
>>> from psycopg2.extras import DateTimeTZRange
|
|
>>> Event.objects.filter(start__contained_by=DateTimeTZRange(
|
|
... timezone.now() - datetime.timedelta(hours=1),
|
|
... timezone.now() + datetime.timedelta(hours=1),
|
|
... )
|
|
[<Event: Soft play>]
|
|
|
|
.. fieldlookup:: rangefield.overlap
|
|
|
|
overlap
|
|
'''''''
|
|
|
|
>>> Event.objects.filter(ages__overlap=NumericRange(8, 12))
|
|
[<Event: Soft play>]
|
|
|
|
Comparison functions
|
|
~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Range fields support the standard lookups: :lookup:`lt`, :lookup:`gt`,
|
|
:lookup:`lte` and :lookup:`gte`. These are not particularly helpful - they
|
|
compare the lower bounds first and then the upper bounds only if necessary.
|
|
This is also the strategy used to order by a range field. It is better to use
|
|
the specific range comparison operators.
|
|
|
|
.. fieldlookup:: rangefield.fully_lt
|
|
|
|
fully_lt
|
|
''''''''
|
|
|
|
The returned ranges are strictly less than the passed range. In other words,
|
|
all the points in the returned range are less than all those in the passed
|
|
range.
|
|
|
|
>>> Event.objects.filter(ages__fully_lt=NumericRange(11, 15))
|
|
[<Event: Soft play>]
|
|
|
|
.. fieldlookup:: rangefield.fully_gt
|
|
|
|
fully_gt
|
|
''''''''
|
|
|
|
The returned ranges are strictly greater than the passed range. In other words,
|
|
the all the points in the returned range are greater than all those in the
|
|
passed range.
|
|
|
|
>>> Event.objects.filter(ages__fully_gt=NumericRange(11, 15))
|
|
[<Event: Pub trip>]
|
|
|
|
.. fieldlookup:: rangefield.not_lt
|
|
|
|
not_lt
|
|
''''''
|
|
|
|
The returned ranges do not contain any points less than the passed range, that
|
|
is the lower bound of the returned range is at least the lower bound of the
|
|
passed range.
|
|
|
|
>>> Event.objects.filter(ages__not_lt=NumericRange(0, 15))
|
|
[<Event: Soft play>, <Event: Pub trip>]
|
|
|
|
.. fieldlookup:: rangefield.not_gt
|
|
|
|
not_gt
|
|
''''''
|
|
|
|
The returned ranges do not contain any points greater than the passed range, that
|
|
is the upper bound of the returned range is at most the upper bound of the
|
|
passed range.
|
|
|
|
>>> Event.objects.filter(ages__not_gt=NumericRange(3, 10))
|
|
[<Event: Soft play>]
|
|
|
|
.. fieldlookup:: rangefield.adjacent_to
|
|
|
|
adjacent_to
|
|
'''''''''''
|
|
|
|
The returned ranges share a bound with the passed range.
|
|
|
|
>>> Event.objects.filter(ages__adjacent_to=NumericRange(10, 21))
|
|
[<Event: Soft play>, <Event: Pub trip>]
|
|
|
|
Querying using the bounds
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
There are three transforms available for use in queries. You can extract the
|
|
lower or upper bound, or query based on emptiness.
|
|
|
|
.. fieldlookup:: rangefield.startswith
|
|
|
|
startswith
|
|
''''''''''
|
|
|
|
Returned objects have the given lower bound. Can be chained to valid lookups
|
|
for the base field.
|
|
|
|
>>> Event.objects.filter(ages__startswith=21)
|
|
[<Event: Pub trip>]
|
|
|
|
.. fieldlookup:: rangefield.endswith
|
|
|
|
endswith
|
|
''''''''
|
|
|
|
Returned objects have the given upper bound. Can be chained to valid lookups
|
|
for the base field.
|
|
|
|
>>> Event.objects.filter(ages__endswith=10)
|
|
[<Event: Soft play>]
|
|
|
|
.. fieldlookup:: rangefield.isempty
|
|
|
|
isempty
|
|
'''''''
|
|
|
|
Returned objects are empty ranges. Can be chained to valid lookups for a
|
|
:class:`~django.db.models.BooleanField`.
|
|
|
|
>>> Event.objects.filter(ages__isempty=True)
|
|
[]
|
|
|
|
Defining your own range types
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
PostgreSQL allows the definition of custom range types. Django's model and form
|
|
field implementations use base classes below, and psycopg2 provides a
|
|
:func:`~psycopg2:psycopg2.extras.register_range` to allow use of custom range
|
|
types.
|
|
|
|
.. class:: RangeField(**options)
|
|
|
|
Base class for model range fields.
|
|
|
|
.. attribute:: base_field
|
|
|
|
The model field to use.
|
|
|
|
.. attribute:: range_type
|
|
|
|
The psycopg2 range type to use.
|
|
|
|
.. attribute:: form_field
|
|
|
|
The form field class to use. Should be a subclass of
|
|
:class:`django.contrib.postgres.forms.BaseRangeField`.
|
|
|
|
.. class:: django.contrib.postgres.forms.BaseRangeField
|
|
|
|
Base class for form range fields.
|
|
|
|
.. attribute:: base_field
|
|
|
|
The form field to use.
|
|
|
|
.. attribute:: range_type
|
|
|
|
The psycopg2 range type to use.
|