bulk_create method works wrong for mysql db

[Mykola Fenyk]

I wrote a small test application for the company's list of employees. 

I wrote the custom migration to create the initial data and got problem with python manage.py migrate

Traceback (most recent call last):
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/backends/mysql/base.py", line 71, in execute
    return self.cursor.execute(query, args)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/MySQLdb/cursors.py", line 255, in execute
    self.errorhandler(self, exc, value)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/MySQLdb/connections.py", line 50, in defaulterrorhandler
    raise errorvalue
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/MySQLdb/cursors.py", line 252, in execute
    res = self._query(query)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/MySQLdb/cursors.py", line 378, in _query
    db.query(q)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/MySQLdb/connections.py", line 280, in query
    _mysql.connection.query(self, query)
_mysql_exceptions.OperationalError: (1048, "Column 'company_id' cannot be null")


During handling of the above exception, another exception occurred:


Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/core/management/base.py", line 316, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/core/management/base.py", line 353, in execute
    output = self.handle(*args, **options)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/core/management/base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 203, in handle
    fake_initial=fake_initial,
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/migrations/executor.py", line 117, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/migrations/migration.py", line 121, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/migrations/operations/special.py", line 190, in database_forwards
    self.code(from_state.apps, schema_editor)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django_print_sql/print_sql.py", line 64, in wrapped
    return func(*fargs, **fkwargs)
  File "/home/mykola/projects/company/departments/migrations/0002_initial_creation_data.py", line 36, in create_objects
    ) for index in range(1, NUMBER)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/models/query.py", line 465, in bulk_create
    ids = self._batched_insert(objs_without_pk, fields, batch_size)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/models/query.py", line 1155, in _batched_insert
    self._insert(item, fields=fields, using=self.db)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/models/query.py", line 1136, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/models/sql/compiler.py", line 1289, in execute_sql
    cursor.execute(sql, params)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/backends/utils.py", line 100, in execute
    return super().execute(sql, params)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/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/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/backends/utils.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "/home/mykola/.virtualenvs/employees/lib/python3.5/site-packages/django/db/backends/mysql/base.py", line 76, in execute
    raise utils.IntegrityError(*tuple(e.args))
django.db.utils.IntegrityError: (1048, "Column 'company_id' cannot be null")

my code of migration:

# Generated by Django 2.1.4 on 2019-01-01 14:37
import names
import random
from django.db import migrations


COMPANY_MODEL = "Company"
COMPANY_NAME = "Codecademy"
NUMBER = 11




def create_objects(apps, schema_editor):


    company_model = apps.get_model("departments", COMPANY_MODEL)
    company = company_model.objects.bulk_create([
        company_model(name=COMPANY_NAME)
    ])[0]


    department_model = apps.get_model("departments", "Department")


    departments = department_model.objects.bulk_create([
        department_model(
            name="Department_{number}".format(
                number=index
            ),
            company=company
        ) for index in range(1, NUMBER)
    ])


    employee_model = apps.get_model("departments", "Employee")


    for department in departments:
        employee_model.objects.bulk_create([
            employee_model(
                name=names.get_full_name(),
                active=random.choice([True, False]),
                department=department
            ) for _ in range(1, NUMBER)
        ])




def rollback_migration(apps, schema_editor):
    company_model = apps.get_model("departments", COMPANY_MODEL)
    company_model.objects.get(name=COMPANY_NAME).delete()




class Migration(migrations.Migration):


    dependencies = [
        ('departments', '0001_initial'),
    ]


    operations = [
        migrations.RunPython(code=create_objects, reverse_code=rollback_migration)
    ]

I plaing in django console and I saw that this bulk_create() method create company object in db, but return [<Company: Company object (None)>] and I can not refresh_from_db() this object because it rise departments.models.Company.DoesNotExist: Company matching query does not exist. 

The most important thing is that there is no problem with postgresql bd!!! Can anyone help me? It looks like I found a bug...

Django version 2.1

project code:

https://bitbucket.org/fenix85/employees_info/src/master/