Bidang-bidang model khusus PostgreSQLLink to this heading
Semua dari bidang ini tersedia dari modul django.contrib.postgres.fields.
Mengindeks bidang-bidang iniLink to this heading
Index and Field.db_index both create a
B-tree index, which isn't particularly helpful when querying complex data
types. Indexes such as GinIndex and
GistIndex are better suited, though
the index choice is dependent on the queries that you're using. Generally, GiST
may be a good choice for the range fields and
HStoreField, and GIN may be helpful for ArrayField.
ArrayFieldLink to this heading
- class ArrayField(base_field, size=None, **options)Link to this definition
A field for storing lists of data. Most field types can be used, and you pass another field instance as the
base_field. You may also specify asize.ArrayFieldcan be nested to store multi-dimensional arrays.Jika anda memberikan bidang
default, pastikan itu adalah callable sepertilist(untuk sebuah nilai kosong) atau sebuah callable yang mengembalikan list (seperti sebuah fungsi). Salah menggunakandefault=[]membuat awalan yang berubah-ubah yaitu dibagi diantara semua contoh dariArrayField.- base_fieldLink to this definition
Ini adalah sebuah argumen diwajibkan.
Specifies the underlying data type and behavior for the array. It should be an instance of a subclass of
Field. For example, it could be anIntegerFieldor aCharField. Most field types are permitted, with the exception of those handling relational data (ForeignKey,OneToOneFieldandManyToManyField) and file fields (FileFieldandImageField).Itu memungkinkan menyarang bidang-bidang larik - anda dapat menentukan sebuah instance dari
ArrayFieldsebagaibase_field. Sebagai contoh:from django.contrib.postgres.fields import ArrayField from django.db import models class ChessBoard(models.Model): board = ArrayField( ArrayField( models.CharField(max_length=10, blank=True), size=8, ), size=8, )Perubahan dari nilai-nilai diantara basisdata dan model, pengesahan dari data dan konfigurasi, dan serialisasi adalah semua dilimpahkan ke bidang dasar pokok.
- sizeLink to this definition
Ini adalah sebuah argumen pilihan.
Jika dilewatkan, larik akan memiliki ukuran maksimal seperti ditentukan. Ini akan dilewatkan ke basisdata meskipun PostgreSQL saat sekarang tidak melaksanakan batasan.
Meminta ArrayFieldLink to this heading
Ada sejumlah pencarian penyesuaian dan merubah untuk ArrayField. Kami akan menggunakan model contoh berikut:
from django.contrib.postgres.fields import ArrayField
from django.db import models
class Post(models.Model):
name = models.CharField(max_length=200)
tags = ArrayField(models.CharField(max_length=200), blank=True)
def __str__(self):
return self.name
containsLink to this heading
The contains lookup is overridden on 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"])
<QuerySet [<Post: First post>, <Post: Second post>]>
>>> Post.objects.filter(tags__contains=["django"])
<QuerySet [<Post: First post>, <Post: Third post>]>
>>> Post.objects.filter(tags__contains=["django", "thoughts"])
<QuerySet [<Post: First post>]>
contained_byLink to this heading
This is the inverse of the 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"])
<QuerySet [<Post: First post>, <Post: Second post>]>
>>> Post.objects.filter(tags__contained_by=["thoughts", "django", "tutorial"])
<QuerySet [<Post: First post>, <Post: Second post>, <Post: Third post>]>
overlapLink to this heading
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", "tutorial"])
>>> Post.objects.create(name="Third post", tags=["tutorial", "django"])
>>> Post.objects.filter(tags__overlap=["thoughts"])
<QuerySet [<Post: First post>, <Post: Second post>]>
>>> Post.objects.filter(tags__overlap=["thoughts", "tutorial"])
<QuerySet [<Post: First post>, <Post: Second post>, <Post: Third post>]>
>>> Post.objects.filter(tags__overlap=Post.objects.values_list("tags"))
<QuerySet [<Post: First post>, <Post: Second post>, <Post: Third post>]>
lenLink to this heading
Returns the length of the array. The lookups available afterward are those
available for 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)
<QuerySet [<Post: Second post>]>
Perubahan indeksLink to this heading
Index transforms index into the array. Any non-negative integer can be used.
There are no errors if it exceeds the size of the
array. The lookups available after the transform are those from the
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")
<QuerySet [<Post: First post>, <Post: Second post>]>
>>> Post.objects.filter(tags__1__iexact="Django")
<QuerySet [<Post: First post>]>
>>> Post.objects.filter(tags__276="javascript")
<QuerySet []>
Perubahan potonganLink to this heading
Slice transforms 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"])
<QuerySet [<Post: First post>, <Post: Second post>]>
>>> Post.objects.filter(tags__0_2__contains=["thoughts"])
<QuerySet [<Post: First post>, <Post: Second post>]>
HStoreFieldLink to this heading
- class HStoreField(**options)Link to this definition
Sebuah bidang untuk menyimpan pasangan nilai-kunci. Jenis data Python adalah sebuah
dict. Kunci-kunci harus berupa string, dan nilai-nilai mungkin salah satu string atau null (Nonedalam Python).Untuk menggunakan bidang ini, anda akan butuh untuk:
Tambah
'django.contrib.postgres'dalamINSTALLED_APPSanda.Set up the hstore extension in PostgreSQL.
Anda akan melihat sebuah kesalahan seperti
can't adapt type 'dict'jika anda melewati langkah pertama, atautype "hstore" does not existjika anda melewati kedua.
Meminta HStoreFieldLink to this heading
Sebagai tambahan pada kemampuan untuk pencarian berdasarkan kunci, ada angka dari pencarian penyesuaian tersedia untuk HStoreField.
Kami akan menggunakan model contoh berikut:
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):
return self.name
Kunci pencarianLink to this heading
To query based on a given key, you can 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")
<QuerySet [<Dog: Meg>]>
You can chain other lookups after key lookups:
>>> Dog.objects.filter(data__breed__contains="l")
<QuerySet [<Dog: Rufus>, <Dog: Meg>]>
or use F() expressions to annotate a key value. For example:
>>> from django.db.models import F
>>> rufus = Dog.objects.annotate(breed=F("data__breed"))[0]
>>> rufus.breed
'labrador'
Jika kunci yang anda ahrapkan untuk meminta berdasarkan ketidakcocokan dengan nama dari pencarian lain, anda butuh menggunakan pencarian hstorefield.contains lookup sebagai gantinya.
containsLink to this heading
The contains lookup is overridden on
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"})
<QuerySet [<Dog: Rufus>, <Dog: Meg>]>
>>> Dog.objects.filter(data__contains={"breed": "collie"})
<QuerySet [<Dog: Meg>]>
contained_byLink to this heading
This is the inverse of the 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"})
<QuerySet [<Dog: Meg>, <Dog: Fred>]>
>>> Dog.objects.filter(data__contained_by={"breed": "collie"})
<QuerySet [<Dog: Fred>]>
has_keyLink to this heading
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")
<QuerySet [<Dog: Meg>]>
has_any_keysLink to this heading
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"])
<QuerySet [<Dog: Rufus>, <Dog: Meg>]>
has_keysLink to this heading
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"])
<QuerySet [<Dog: Meg>]>
keysLink to this heading
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
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"])
<QuerySet [<Dog: Rufus>, <Dog: Meg>]>
valuesLink to this heading
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
ArrayField. Uses the SQL function
avals(). 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"])
<QuerySet [<Dog: Meg>]>
Bidang JangkauanLink to this heading
Ada lima jenis jangkauan bidang, berhubungan ke jenis jangkauan siap-pakai dalam PostgreSQL. Bidang-bidang ini digunakan untuk menyimpan jangkauan dari nilai; sebagai contoh stempel waktu awal dan akhir dari sebuah acara, atau jangkauan dari umur sebuah aktivitas yang cocok.
All of the range fields translate to psycopg Range objects in Python, but also accept tuples as input if no bounds
information is necessary. The default is lower bound included, upper bound
excluded, that is [) (see the PostgreSQL documentation for details about
different bounds). The default bounds can be changed for non-discrete range
fields (DateTimeRangeField and DecimalRangeField) by using
the default_bounds argument.
IntegerRangeFieldLink to this heading
- class IntegerRangeField(**options)Link to this definition
Stores a range of integers. Based on an
IntegerField. Represented by anint4rangein the database and adjango.db.backends.postgresql.psycopg_any.NumericRangein Python.Regardless of the bounds specified when saving the data, PostgreSQL always returns a range in a canonical form that includes the lower bound and excludes the upper bound, that is
[).
BigIntegerRangeFieldLink to this heading
- class BigIntegerRangeField(**options)Link to this definition
Stores a range of large integers. Based on a
BigIntegerField. Represented by anint8rangein the database and adjango.db.backends.postgresql.psycopg_any.NumericRangein Python.Regardless of the bounds specified when saving the data, PostgreSQL always returns a range in a canonical form that includes the lower bound and excludes the upper bound, that is
[).
DecimalRangeFieldLink to this heading
- class DecimalRangeField(default_bounds='[)', **options)Link to this definition
Stores a range of floating point values. Based on a
DecimalField. Represented by anumrangein the database and adjango.db.backends.postgresql.psycopg_any.NumericRangein Python.- default_boundsLink to this definition
Optional. The value of
boundsfor list and tuple inputs. The default is lower bound included, upper bound excluded, that is[)(see the PostgreSQL documentation for details about different bounds).default_boundsis not used fordjango.db.backends.postgresql.psycopg_any.NumericRangeinputs.
DateTimeRangeFieldLink to this heading
- class DateTimeRangeField(default_bounds='[)', **options)Link to this definition
Stores a range of timestamps. Based on a
DateTimeField. Represented by atstzrangein the database and adjango.db.backends.postgresql.psycopg_any.DateTimeTZRangein Python.- default_boundsLink to this definition
Optional. The value of
boundsfor list and tuple inputs. The default is lower bound included, upper bound excluded, that is[)(see the PostgreSQL documentation for details about different bounds).default_boundsis not used fordjango.db.backends.postgresql.psycopg_any.DateTimeTZRangeinputs.
DateRangeFieldLink to this heading
- class DateRangeField(**options)Link to this definition
Stores a range of dates. Based on a
DateField. Represented by adaterangein the database and adjango.db.backends.postgresql.psycopg_any.DateRangein Python.Regardless of the bounds specified when saving the data, PostgreSQL always returns a range in a canonical form that includes the lower bound and excludes the upper bound, that is
[).
Meminta Jangkauan BidangLink to this heading
Ada sejumlah pencarian penyesuaian dan perubahan untuk bidang jangkauan. Mereka tersedia pada semua bidang-bidang diatas, tetapi kami akan menggunakan model contoh berikut:
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):
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)
... )
dan NumericRange:
>>> from django.db.backends.postgresql.psycopg_any import NumericRange
Fungsi-fungsi penahananLink to this heading
Seperti bidang-bidang PostgreSQL lainnya, ada tiga standar penahanan penghubung: contains, contained_by dan overlap, menggunakan penghubung SQL @>, <@, dan && masing-masing.
containsLink to this heading
>>> Event.objects.filter(ages__contains=NumericRange(4, 5))
<QuerySet [<Event: Soft play>]>
contained_byLink to this heading
>>> Event.objects.filter(ages__contained_by=NumericRange(0, 15))
<QuerySet [<Event: Soft play>]>
The contained_by lookup is also available on the non-range field types:
SmallAutoField,
AutoField, BigAutoField,
SmallIntegerField,
IntegerField,
BigIntegerField,
DecimalField, FloatField,
DateField, and
DateTimeField. For example:
>>> from django.db.backends.postgresql.psycopg_any import DateTimeTZRange
>>> Event.objects.filter(
... start__contained_by=DateTimeTZRange(
... timezone.now() - datetime.timedelta(hours=1),
... timezone.now() + datetime.timedelta(hours=1),
... ),
... )
<QuerySet [<Event: Soft play>]>
overlapLink to this heading
>>> Event.objects.filter(ages__overlap=NumericRange(8, 12))
<QuerySet [<Event: Soft play>]>
Fungsi perbandinganLink to this heading
Bidang jangkauan mendukung pencarian standar: lt, gt, lte dan gte. Ini tidak terlalu membantu - mereka membandingkan batasan terendah dahulu dan batasan tertinggi hanya jika dibutuhkan. Ini juga strategi digunakan untuk mengurutkan berdasarkan bidang jangkauan. Itu lebih baik menggunakan penghubung perbandingan jangkauan khusus.
fully_ltLink to this heading
Jangkauan dikembalikan adalah sangat kurang dari jangkauan dilewatkan. Dengan kata lain, semua titik dalam jangkauan dikembalikan kurang dari semua dalam jangkauan dilewatkan.
>>> Event.objects.filter(ages__fully_lt=NumericRange(11, 15))
<QuerySet [<Event: Soft play>]>
fully_gtLink to this heading
Jangkauan dikembalikan adalah lebih besar dari jangkauan dilewatkan. Dengan kata lain, semua titik dalam jangkauan dikembalikan lebih besar dari semua dalam jangkauan dilewatkan.
>>> Event.objects.filter(ages__fully_gt=NumericRange(11, 15))
<QuerySet [<Event: Pub trip>]>
not_ltLink to this heading
Jangkauan dikembalikan tidak mengandung titik apapun kurang dari jangkauan dilewatkan, yaitu batasan terendah dari jangkauan dikembalikan adalah setidaknya batasan terendah dari jangkauan dilewatkan.
>>> Event.objects.filter(ages__not_lt=NumericRange(0, 15))
<QuerySet [<Event: Soft play>, <Event: Pub trip>]>
not_gtLink to this heading
Jangkauan dikembalikan tidak mengandung titik apapun lebih besar dari jangkauan dilewatkan, yaitu batasan tertinggi dari jangkauan dikembalikan adalah batasan paling tertinggi dari jangkauan dilewatkan.
>>> Event.objects.filter(ages__not_gt=NumericRange(3, 10))
<QuerySet [<Event: Soft play>]>
adjacent_toLink to this heading
Jangkauan dikembalikan berbagi sebuah batasan dengan jangkauan dilewatkan.
>>> Event.objects.filter(ages__adjacent_to=NumericRange(10, 21))
<QuerySet [<Event: Soft play>, <Event: Pub trip>]>
Meminta menggunakan batasanLink to this heading
Range fields support several extra lookups.
startswithLink to this heading
Obyek-obyek dikembalikan memiliki batasan terendah diberikan. Dapat diikat untuk pencarian sah untuk bidang dasar.
>>> Event.objects.filter(ages__startswith=21)
<QuerySet [<Event: Pub trip>]>
endswithLink to this heading
Obyek-obyek dikembalikan memiliki batasan tertinggi diberikan. Dapat diikat untuk pencarian sah untuk bidang dasar.
>>> Event.objects.filter(ages__endswith=10)
<QuerySet [<Event: Soft play>]>
isemptyLink to this heading
Obyek-obyek dikembalikan adalah jangkauan kosong. Dapat diikat untuk pencarian sah untuk BooleanField.
>>> Event.objects.filter(ages__isempty=True)
<QuerySet []>
lower_incLink to this heading
Returns objects that have inclusive or exclusive lower bounds, depending on the
boolean value passed. Can be chained to valid lookups for a
BooleanField.
>>> Event.objects.filter(ages__lower_inc=True)
<QuerySet [<Event: Soft play>, <Event: Pub trip>]>
lower_infLink to this heading
Returns objects that have unbounded (infinite) or bounded lower bound,
depending on the boolean value passed. Can be chained to valid lookups for a
BooleanField.
>>> Event.objects.filter(ages__lower_inf=True)
<QuerySet []>
upper_incLink to this heading
Returns objects that have inclusive or exclusive upper bounds, depending on the
boolean value passed. Can be chained to valid lookups for a
BooleanField.
>>> Event.objects.filter(ages__upper_inc=True)
<QuerySet []>
upper_infLink to this heading
Returns objects that have unbounded (infinite) or bounded upper bound,
depending on the boolean value passed. Can be chained to valid lookups for a
BooleanField.
>>> Event.objects.filter(ages__upper_inf=True)
<QuerySet [<Event: Pub trip>]>
Menentukan jenis jangkauan anda sendiriLink to this heading
PostgreSQL allows the definition of custom range types. Django's model and form
field implementations use base classes below, and psycopg provides a
register_range() to allow use of custom
range types.
- class RangeField(**options)Link to this definition
Kelas dasar untuk bidang jangkauan model.
- base_fieldLink to this definition
Kelas bidang model digunakan.
- range_typeLink to this definition
The range type to use.
- form_fieldLink to this definition
Kelas bidang formulir digunakan. Harus berupa subkelas dari
django.contrib.postgres.forms.BaseRangeField.
- class django.contrib.postgres.forms.BaseRangeFieldLink to this definition
Kelas dasar untuk formulir bidang jangkauan.
- base_fieldLink to this definition
Bidang formulir digunakan.
- range_typeLink to this definition
The range type to use.
Range operatorsLink to this heading
- class RangeOperatorsLink to this definition
PostgreSQL provides a set of SQL operators that can be used together with the range data types (see the PostgreSQL documentation for the full details of range operators). This class is meant as a convenient method to avoid typos. The operator names overlap with the names of corresponding lookups.
class RangeOperators:
EQUAL = "="
NOT_EQUAL = "<>"
CONTAINS = "@>"
CONTAINED_BY = "<@"
OVERLAPS = "&&"
FULLY_LT = "<<"
FULLY_GT = ">>"
NOT_LT = "&>"
NOT_GT = "&<"
ADJACENT_TO = "-|-"
Pernyataan RangeBoundary()Link to this heading
- class RangeBoundary(inclusive_lower=True, inclusive_upper=False)Link to this definition
- inclusive_lowerLink to this definition
If
True(default), the lower bound is inclusive'[', otherwise it's exclusive'('.
- inclusive_upperLink to this definition
If
False(default), the upper bound is exclusive')', otherwise it's inclusive']'.
A RangeBoundary() expression represents the range boundaries. It can be
used with a custom range functions that expected boundaries, for example to
define ExclusionConstraint. See
the PostgreSQL documentation for the full details.