Django backend for Snowflake
Project description
Snowflake backend for Django
Install and usage
Use the version of django-snowflake that corresponds to your version of Django. For example, to get the latest compatible release for Django 5.1.x:
pip install django-snowflake==5.1.*
The minor release number of Django doesn't correspond to the minor release number of django-snowflake. Use the latest minor release of each.
Configure the Django DATABASES
setting similar to this:
DATABASES = {
'default': {
'ENGINE': 'django_snowflake',
'NAME': 'MY_DATABASE',
'SCHEMA': 'MY_SCHEMA',
'WAREHOUSE': 'MY_WAREHOUSE',
'USER': 'my_user',
'PASSWORD': 'my_password',
'ACCOUNT': 'my_account',
# Include 'OPTIONS' if you need to specify any other
# snowflake.connector.connect() parameters, documented at:
# https://docs.snowflake.com/en/user-guide/python-connector-api.html#connect
'OPTIONS': {
# Examples:
'role': 'MY_ROLE',
# To use native Okta authenticators:
# https://docs.snowflake.com/en/user-guide/admin-security-fed-auth-use#native-sso-okta-only
'authenticator': 'https://example.okta.com',
# To use private key authentication:
'private_key_file': '<path>/rsa_key.p8',
'private_key_file_pwd': 'my_passphrase',
},
},
}
Persistent connections
To use persisent connections, set Django's CONN_MAX_AGE
and Snowflake Python Connector's client_session_keep_alive
:
DATABASES = {
'default': {
# ...
'CONN_MAX_AGE': None,
'OPTIONS': {
'client_session_keep_alive': True,
},
},
}
Notes on Django fields
-
Consistent with Snowflake's convention, this backend uppercases all database identifiers (table names, column names, etc.) unless they are quoted, e.g.
db_table='"table_name"'
. -
Snowflake supports defining foreign key and unique constraints, however, it doesn't enforce them. Thus, Django manages these constraints and
inspectdb
detects them, but Django won't raiseIntegrityError
if they're violated. -
Snowflake doesn't support indexes. Thus, Django ignores any indexes defined on models or fields.
-
Snowflake doesn't support check constraints, so the various
PositiveIntegerField
model fields allow negative values (though validation at the form level still works).
Notes on Django QuerySets
-
Snowflake has limited support for subqueries.
-
Valid values for
QuerySet.explain()
'sformat
parameter are'json'
,'tabular'
, and'text'
. The default is'tabular'
.
Known issues and limitations
This list isn't exhaustive. If you run into a problem, consult
django_snowflake/features.py
to see if a similar test is skipped. Please
create an issue on GitHub
if you encounter an issue worth documenting.
-
Snowflake doesn't support
last_insert_id
to retrieve the ID of a newly created object. Instead, this backend issues the querySELECT MAX(pk_name) FROM table_name
to retrieve the ID. This is subject to race conditions if objects are created concurrently. This makes this backend inappropriate for use in web app use cases where multiple clients could be creating objects at the same time. Further, you should not manually specify an ID (e.g.MyModel(id=1)
) when creating an object. -
Due to snowflake-connector-python's lack of VARIANT support, some
JSONField
queries with complex JSON parameters don't work.For example, if
value
is aJSONField
, this won't work:>>> JSONModel.objects.filter(value__k={"l": "m"})
A workaround is:
>>> from django.db.models.expressions import RawSQL >>> JSONModel.objects.filter(value__k=RawSQL("PARSE_JSON(%s)", ('{"l": "m"}',)))
In addition,
QuerySet.bulk_update()
isn't supported forJSONField
. -
Interval math where the interval is a column is not supported.
-
Interval math with a null interval crashes.
Troubleshooting
Debug logging
To troubleshoot issues with connectivity to Snowflake, you can enable
Snowflake Connector for Python's logging
using Django's LOGGING
setting.
This is a minimal addition to Django's default "loggers"
configuration that
enables the connector's DEBUG
logging:
LOGGING = {
…
"loggers": {
…
"snowflake.connector": {
"level": "DEBUG",
"handlers": ["console"],
},
},
}
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