Django: create Index: non-unique, multiple column
Given the following model, I want to index the fields (sequence,stock)
class QuoteModel(models.Model):
quotedate = models.DateField()
high = models.FloatField() #(9,2) DEFAULT NULL,
low = models.FloatField() #(9,2) DEFAULT NULL,
close = models.FloatField() #(9,2) DEFAULT NULL,
closeadj = models.FloatField() #(9,2) DEFAULT NULL,
volume = models.IntegerField() #(9,2) DEFAULT NULL,
stock = models.IntegerField(db_index=True) #(9,2) DEFAULT NULL,
open = models.FloatField() #(9,2) DEFAULT NULL,
sequence = models.IntegerField() #(9,2) DEFAULT NULL,
This index should be non-unique - in mysql it should be something like:
create index ndx_1 on model_quotemodel(sequence,stock);
The only Django workaround I know of is creating an "sql" file that will be executed by django upon table c开发者_StackOverflow中文版reation. So, I created a "stockmodel.sql" containing the following query (same as above:)
create index ndx_1 on model_quotemodel(sequence,stock);
Is there any "cleaner" way of doing it?
As of Django 1.5, you can use the Meta.index_together
option:
class QuoteModel(models.Model):
# ... fields ...
class Meta:
index_together = [
("sequence", "stock"),
]
(note: the original answer from 2009 said it was not possible to index multiple fields; it has since been replaced)
There is a ticket for this feature. Take a look http://code.djangoproject.com/ticket/5805
You may apply the patch from this ticket yourself.
UPDATE
It's now in Django: https://docs.djangoproject.com/en/1.5/ref/models/options/#django.db.models.Options.index_together
To follow on from the accepted answer, if you are using South, you can easily add a composite key as follows:
manage.py schemamigration your_app_name name_for_migration --add-index ModelName.first_field_in_index
You can then edit the generated migration file to add the additional fields into the one index (you'll see it's just a list of field names that's needed).
Don't forget to update the reverse migration as well as the forward one.
It is index_together in django 1.5
See here https://docs.djangoproject.com/en/dev/ref/models/options/#index-together
unique_together
might be what you are looking for. Just put it in your Meta
class inside your model.
The index_together feature could be deprecated in the futur.
You should use indexes option instead of index_together.
Example of indexes option :
from django.db import models
class Customer(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
class Meta:
indexes = [
models.Index(fields=['last_name', 'first_name']),
models.Index(fields=['first_name'], name='first_name_idx'),
]
I just wanted to add that as of Django 1.11 there is a new feature, Options.indexes, which will allow you to specify the indexes to create:
Django Options.indexes
Update for 2022:
The newer indexes
option provides more functionality than index_together
. index_together
was deprecated in Django 4.1.
Usage:
from django.db import models
class Customer(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
class Meta:
indexes = [
models.Index(fields=['last_name', 'first_name']),
models.Index(fields=['first_name'], name='first_name_idx'),
]
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