module 'django.db.backends.utils' has no attribute 'typecast_decimal'

Question

When I run

python manage.py inspectdb --database=sybase_database

it ends with error message:

Database.register_converter(Database.DT_DECIMAL, util.typecast_decimal) AttributeError: module 'django.db.backends.utils' has no attribute 'typecast_decimal'

$ pip freeze
certifi==2021.10.8
chardet==3.0.4
defusedxml==0.7.1
Django==2.2.4
django-allauth==0.40.0
django-bootstrap-form==3.4
django-bootstrap3==15.0.0
django-crispy-forms==1.7.2
django-crudbuilder==0.2.7
django-debug-toolbar==1.10.1
django-filter==2.2.0
django-mssql-backend==2.8.1
django-tables2==2.4.1
idna==2.8
importlib-metadata==2.1.1
oauthlib==3.1.1
pyodbc==4.0.32
python-dateutil==2.8.2
python3-openid==3.2.0
pytz==2021.3
requests==2.21.0
requests-oauthlib==1.3.0
six==1.16.0
sqlany-django==1.13
sqlanydb==1.0.11
sqlparse==0.4.2
urllib3==1.24.3
zipp==3.6.0

Ubuntu 18.04

score 1 · Answer 1 · answered Jan 14 '22 at 10:26

1

Replaced typecast_decimal() with decimal.Decimal()

change base.py code like to

Database.register_converter("decimal", decoder(decimal.Decimal))

and in utils.py you can return

decimal.Decimal()

maybe help to you

answered Jan 14 '22 at 10:26

abolfazlmalekahmadi

218
2
16

What is the line number in `utils.py`? I don't understand here, what to replace... – xralf Jan 14 '22 at 10:46
correction: Should I change this line `Database.register_converter(Database.DT_DECIMAL, util.typecast_decimal)` in `base.py` to `Database.register_converter("decimal", decoder(decimal.Decimal))`? – xralf Jan 14 '22 at 10:52
yes and in your utils.py if you dont have typecast_decimal function created and in your expression import Decimal from decimal – abolfazlmalekahmadi Jan 14 '22 at 15:28
And you can see here https://github.com/maxirobaina/django-firebird/issues/102 – abolfazlmalekahmadi Jan 14 '22 at 15:30
And what should I replace by what in `utils.py`? – xralf Jan 14 '22 at 16:01
1

util.typecast_decimal to decimal.Decimal() – abolfazlmalekahmadi Jan 14 '22 at 16:31
Thanks, I will try it on monday. – xralf Jan 14 '22 at 20:16
In `my_app/env/lib/python3.6/site-packages/django/db/utils.py` there is not `typecast_decimal`. – xralf Jan 18 '22 at 09:11
change in base.py and use as function on utils.py – abolfazlmalekahmadi Jan 18 '22 at 18:48
like this : https://github.com/django/django/commit/f3e350d6318c20d0d5e2f53f278b9dcc326e1d74#diff-1132e403debb86cff5e5dd3366985796 – abolfazlmalekahmadi Jan 18 '22 at 18:49

aaron · Accepted Answer · 2022-01-22T16:49:53.903

sqlany-django only supports up to Django 1.8.5 (Django 1.7.0 for inspectdb command).
It is no longer maintained; it was last updated in May 2016.

You can patch for later versions of Django in manage.py or an AppConfig.

# Django >= 2.0, for sqlany_django/base.py
import decimal
from django.db.backends import utils
utils.typecast_decimal = decimal.Decimal

# Django >= 1.11, for BaseDatabaseWrapper
from sqlany_django.base import DatabaseWrapper
DatabaseWrapper.client_class = lambda self, connection: None
DatabaseWrapper.creation_class = lambda self, connection: None
DatabaseWrapper.features_class = lambda self, connection: None
DatabaseWrapper.introspection_class = lambda self, connection: None
DatabaseWrapper.ops_class = lambda self, connection: None

# Django >= 1.7.1, for inspectdb
from django.db.backends import utils
from sqlany_django import base
class CursorWrapper(base.CursorWrapper, utils.CursorWrapper):
    pass
base.CursorWrapper = CursorWrapper

References:

https://github.com/django/django/pull/2154 regarding CursorWrapper
https://github.com/django/django/pull/7206 regarding DatabaseWrapper
https://github.com/django/django/pull/8889 regarding typecast_decimal
https://github.com/sqlanywhere/sqlany-django/pull/15 regarding typecast_decimal
https://sqlanywhere-forum.sap.com/questions/37563/sqlany-django-driver-upgrade-to-django-32 requesting an update to sqlany_django (unanswered as of this post)

Stack traces:

Regarding DatabaseWrapper

Traceback (most recent call last):
  ...
  File "/path/to/site-packages/django/core/management/commands/inspectdb.py", line 40, in handle_inspection
    connection = connections[options['database']]
  File "/path/to/site-packages/django/db/utils.py", line 207, in __getitem__
    conn = backend.DatabaseWrapper(db, alias)
  File "/path/to/site-packages/sqlany_django/base.py", line 447, in __init__
    super(DatabaseWrapper, self).__init__(*args, **kwargs)
  File "/path/to/site-packages/django/db/backends/base/base.py", line 102, in __init__
    self.client = self.client_class(self)
TypeError: 'NoneType' object is not callable

Regarding CursorWrapper

Traceback (most recent call last):
  ...
  File "/path/to/site-packages/django/core/management/commands/inspectdb.py", line 47, in handle_inspection
    with connection.cursor() as cursor:
AttributeError: __enter__

Thanks, I will try it on monday. But I think I can accept it, Django 1.8 solved it, but I have to find out, how to run two Django projects on one IP address. Don't you possibly know some link where is it described or should I rather ask another question? — xralf, Jan 22 '22 at 17:39
I tried it now and it's better. Now there is an error `Unable to inspect table 'xxx' # The error was: subclasses of BaseDatabaseIntrospection may require a get_constraints() method ` — xralf, Jan 28 '22 at 11:42
Can you share the stack trace? (Or do you use TeamVIewer? I don't have a Sybase DB to test with.) — aaron, Jan 28 '22 at 12:09

module 'django.db.backends.utils' has no attribute 'typecast_decimal'

2 Answers2

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