Saving data fails because of null constraint when data is not null

Django - constraint error

I have the following python code in django which is deployed on heroku:

def newimportdb(request):

import xlrd

loc = ("./CGHS Rates 2014- Trivandrum.xlsx")

wb = xlrd.open_workbook(loc)

sheet = wb.sheet_by_index(0)

for i in range(sheet.nrows):

try:

sl = int(sheet.cell_value(i, 0))

except:

title = sheet.cell_value(i, 1)

hd = CGHSSection(title = title)

try:

hd.save()

heading = CGHSSection.objects.get(title = title)

print(f"Saved new heading: {title}")

continue

except:

print(f"Could not save new section: {title}. Maybe it existing. Reading it.")

heading = CGHSSection.objects.get(title = title)

continue

test = sheet.cell_value(i, 1)

nonnabh = int(sheet.cell_value(i, 2))

nabh = int(sheet.cell_value(i, 3))

print(f'{i} Test:{test} NonNABH:{nonnabh} NABH:{nabh} Under:{heading}')

it = CGHSRates(serial = sl, name =test, NABHrate = nabh, NonNrate=nonnabh, section=heading)

print(f"Value of section heading is {heading.title}")

print(f'it = CGHSRates(serial = {sl}, name ={test}, NABHrate = {nabh}, NonNrate={nonnabh}, section={heading}')

it.save()

print("Saved")

In my models, I have:

from django.db import models

class CGHSRates(models.Model):

rid = models.AutoField(primary_key=True)

serial = models.IntegerField(default=0)

name = models.CharField(max_length=100)

NonNrate = models.FloatField(blank=True)

NABHrate = models.FloatField(blank=True)

section = models.ForeignKey('CGHSSection', on_delete=models.SET_NULL, null=True, blank=True)

class Meta:

unique_together = ('name', 'NonNrate', 'NABHrate')

class CGHSSection(models.Model):

num = models.AutoField(primary_key=True)

title = models.CharField(max_length=150, unique=True)

On running the above, I get:

[22/Dec/2018 09:07:55] "GET /favicon.ico/ HTTP/1.1" 404 3346

Could not save new section: UNCLASSIFIED. Maybe it existing. Reading it.

1 Test:Consultation OPD NonNABH:135 NABH:135 Under:CGHSSection object (1)

Value of section heading is UNCLASSIFIED

it = CGHSRates(serial = 1, name =Consultation OPD, NABHrate = 135, NonNrate=135, section=CGHSSection object (1)

Internal Server Error: /app/import

Traceback (most recent call last):

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute

return self.cursor.execute(sql, params)

psycopg2.IntegrityError: null value in column "section" violates not-null constraint

DETAIL: Failing row contains (3, 1, Consultation OPD, 135, 135, null, 1).

The above exception was the direct cause of the following exception:

Traceback (most recent call last):

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 34, in inner

response = get_response(request)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 126, in _get_response

response = self.process_exception_by_middleware(e, request)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 124, in _get_response

response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/home/joel/peroorkada/app/views.py", line 134, in newimportdb

it.save()

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/models/base.py", line 718, in save

force_update=force_update, update_fields=update_fields)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/models/base.py", line 748, in save_base

updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/models/base.py", line 831, in _save_table

result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/models/base.py", line 869, in _do_insert

using=using, raw=raw)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/models/manager.py", line 82, in manager_method

return getattr(self.get_queryset(), name)(*args, **kwargs)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/models/query.py", line 1136, in _insert

return query.get_compiler(using=using).execute_sql(return_id)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1289, in execute_sql

cursor.execute(sql, params)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 100, in execute

return super().execute(sql, params)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 68, in execute

return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 77, in _execute_with_wrappers

return executor(sql, params, many, context)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute

return self.cursor.execute(sql, params)

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/utils.py", line 89, in __exit__

raise dj_exc_value.with_traceback(traceback) from exc_value

File "/home/joel/sampledjango/venv/lib/python3.6/site-packages/django/db/backends/utils.py", line 85, in _execute

return self.cursor.execute(sql, params)

django.db.utils.IntegrityError: null value in column "section" violates not-null constraint

DETAIL: Failing row contains (3, 1, Consultation OPD, 135, 135, null, 1).

I cant understand why this is happening. My print just before saving data shows that section is not null. However that seems to be the error I'm getting

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