ArrayField - a PostgreSQL-specific field 1.8–1.9

Examples

• 3

  Querying for membership of ArrayField with contains

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  3

  This query returns all cones with a chocolate scoop and a vanilla scoop.

  VANILLA, CHOCOLATE, MINT, STRAWBERRY = 1, 2, 3, 4  # constants for flavors
  choco_vanilla_cones = IceCream.objects.filter(scoops__contains=[CHOCOLATE, VANILLA])
  

  Don't forget to import the IceCream model from your models.py file.

  Also bear in mind that django will not create an index for ArrayFields. If you are going to search them, you are going to need an index and that index will need to be manually created with a call to RunSQL in your migrations file.

  edited Jul 22 at 9:04

  

  
• 2

  A basic ArrayField

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  2

  To create a PostgreSQL ArrayField, we should give ArrayField the type of data we want it to store as a field as its first argument. Since we'll be storing book ratings, we will use FloatField.

   from django.db import models, FloatField
   from django.contrib.postgres.fields import ArrayField
   
   class Book(models.Model):
       ratings = ArrayField(FloatField())
  

  created Jul 21 at 21:30

  
• 1

  Nesting ArrayFields

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  1

  You can nest ArrayFields by passing another ArrayField as it's base_field.

  from django.db import models, IntegerField
  from django.contrib.postgres.fields import ArrayField
  
  class SudokuBoard(models.Model):
      numbers = ArrayField(
          ArrayField(
              models.IntegerField(),
              size=9,
          ),
          size=9,
      )
  

  created Jul 21 at 21:30

  
• 0

  Querying for all models who contain any item in a list with contained_by

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  0

  This query returns all cones with either a mint scoop or a vanilla scoop.

  minty_vanilla_cones = IceCream.objects.filter(scoops__contained_by=[MINT, VANILLA])
  

  created Jul 21 at 21:30

  
• 0

  Specifying the maximum size of an ArrayField

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  0

   from django.db import models, IntegerField
   from django.contrib.postgres.fields import ArrayField
   
   class IceCream(models.Model):
       scoops = ArrayField(IntegerField()  # we'll use numbers to ID the scoops
                     , size=6)  # our parlor only lets you have 6 scoops
  

  When you use the size parameter, it's passed through to postgresql, which accepts it and then ignores it! Thus it's quite possible to add 7 integers to the scoops field above using the postgresql console.

  edited Jul 22 at 19:12