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Django manage.py migrate errors

I've been working on a project for CS50-Web for a while now and I was changing some of my models trying to add a unique attribute to some things. Long story short it wasn't working how I wanted so I went back to how I had it previously and now something is wrong and I can get it to migrate the changes to the model. I don't understand what to do because it was working fine before. Please can someone help I so frustrated and annoyed that I've broken it after so many hours of work. Sorry I know this error code is long but I don't know which part is important.
Error code
Operations to perform:
Apply all migrations: admin, auth, contenttypes, network, sessions
Running migrations:
Applying network.0019_alter_follower_user...Traceback (most recent call last):
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\sqlite3\base.py", line 416, in execute
return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: UNIQUE constraint failed: new__network_follower.user_id
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "C:\Users\caitw\Documents\GitHub\CS50-Web\Project-4-Network\project4\manage.py", line 21, in <module>
main()
File "C:\Users\caitw\Documents\GitHub\CS50-Web\Project-4-Network\project4\manage.py", line 17, in main
execute_from_command_line(sys.argv)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\core\management\__init__.py", line 425, in execute_from_command_line
utility.execute()
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\core\management\__init__.py", line 419, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\core\management\base.py", line 373, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\core\management\base.py", line 417, in execute
output = self.handle(*args, **options)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\core\management\base.py", line 90, in wrapped
res = handle_func(*args, **kwargs)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\core\management\commands\migrate.py", line 253, in handle
post_migrate_state = executor.migrate(
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\migrations\executor.py", line 126, in migrate
state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\migrations\executor.py", line 156, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\migrations\executor.py", line 236, in apply_migration
state = migration.apply(state, schema_editor)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\migrations\migration.py", line 125, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\migrations\operations\fields.py", line 225, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\sqlite3\schema.py", line 140, in alter_field
super().alter_field(model, old_field, new_field, strict=strict)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\base\schema.py", line 620, in alter_field
self._alter_field(model, old_field, new_field, old_type, new_type,
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\sqlite3\schema.py", line 362, in _alter_field
self._remake_table(model, alter_field=(old_field, new_field))
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\sqlite3\schema.py", line 285, in _remake_table
self.execute("INSERT INTO %s (%s) SELECT %s FROM %s" % (
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\base\schema.py", line 153, in execute
cursor.execute(sql, params)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\utils.py", line 99, in execute
return super().execute(sql, params)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\utils.py", line 67, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\utils.py", line 76, in _execute_with_wrappers
return executor(sql, params, many, context)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\utils.py", line 85, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\caitw\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\django\db\backends\sqlite3\base.py", line 416, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: new__network_follower.user_id
I went back to how I had the code before it failed but it doesn't work now

Just try these 3 commands for migrations:
python manage.py makemigrations appname
python manage.py sqlmigrate appname 0001 #This value will generate afte makemigrations. it can be either 0001, 0002 or more.
python manage.py migrate
And see if it solves this error

django.db.utils.IntegrityError: CHECK constraint failed

when I am migrating I am getting the error django.db.utils.IntegrityError: CHECK constraint failed. I am using django-cms. this error popped up after trying to add editor.js to the project
full Error:
Applying advita.0003_auto_20220615_1506...Traceback (most recent call last):
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\sqlite3\base.py", line 413, in execute
return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: CHECK constraint failed: (JSON_VALID("sub_title") OR "sub_title" IS NULL)
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File ".\manage.py", line 22, in <module>
main()
File ".\manage.py", line 18, in main
execute_from_command_line(sys.argv)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\__init__.py", line 401, in execute_from_command_line
utility.execute()
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\__init__.py", line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\base.py", line 330, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\base.py", line 371, in execute
output = self.handle(*args, **options)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\base.py", line 85, in wrapped
res = handle_func(*args, **kwargs)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\core\management\commands\migrate.py", line 243, in handle
post_migrate_state = executor.migrate(
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\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 "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\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 "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\migrations\executor.py", line 227, in apply_migration
state = migration.apply(state, schema_editor)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\migrations\migration.py", line 124, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\migrations\operations\fields.py", line 236, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\sqlite3\schema.py", line 138, in alter_field
super().alter_field(model, old_field, new_field, strict=strict)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\base\schema.py", line 571, in alter_field
self._alter_field(model, old_field, new_field, old_type, new_type,
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\sqlite3\schema.py", line 360, in _alter_field
self._remake_table(model, alter_field=(old_field, new_field))
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\sqlite3\schema.py", line 283, in _remake_table
self.execute("INSERT INTO %s (%s) SELECT %s FROM %s" % (
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\base\schema.py", line 142, in execute
cursor.execute(sql, params)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\utils.py", line 98, in execute
return super().execute(sql, params)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\utils.py", line 66, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\utils.py", line 75, in _execute_with_wrappers
return executor(sql, params, many, context)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\mulla\AppData\Local\Programs\Python\Python38\lib\site-packages\django\db\backends\sqlite3\base.py", line 413, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: CHECK constraint failed: (JSON_VALID("sub_title") OR "sub_title" IS NULL)
Can anyone clarify why I am getting this error?

You Faced This IntergrityError Because Your model sub_title does not have a null Field and You Direct do Change JsonField.
JsonField required null=True and Previous Field (sub_title) doesn't have null=True which means you have some value in those filed. After your migrations that Field already has value in the String for that reason, you got this error
django.db.utils.IntegrityError: CHECK constraint failed: (JSON_VALID("sub_title") OR "sub_title" IS NULL)
put that same Previous field and Add Constraint Null=True then apply migration after successful migration used then remove all Value from those Filed
Then You Change CharFiled to JsonField with constraint Null=True, Blank=True
JSONField(_("Sub Title"), blank=True, null=True)
Then apply Migration. it will definitely help you resolve this problem.

This is happening because field 'sub_title' has values earlier which are not valid json.
Table probably already has values for 'sub_title' field and you are changing trying to change earlier fieldtype to jsonfield if this is the case, you should update all values to valid json first.

"Unique constrainted failed" problem when running migrations

I have been tryed to change a django model by applying and running migrations but I have been getting this error django.db.utils.IntegrityError: UNIQUE constraint failed: new__startup_home_mates.user_id How can this error be fixed? I have already investigated a lot but I have found nothing that fits my situation. I have already tried to use RenameField and AlterField directly from the migrations file and it is still not working maybe I was doing it wrong.
models.py
class Mates(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='usermates', unique=True)
users_requests = models.ManyToManyField(User, related_name="users_requests")
req_bio = models.CharField(max_length=400)
req_image = models.ImageField(upload_to='requestmates_pics', null=True, blank=True, default=False)
traceback
Traceback (most recent call last):
File "manage.py", line 21, in <module>
main()
File "manage.py", line 17, in main
execute_from_command_line(sys.argv)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\core\management\__init__.py", line 401, in execute_from_command_line
utility.execute()
File "C:\Users\USER\Envs\startup\lib\site-packages\django\core\management\__init__.py", line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\core\management\base.py", line 328, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\core\management\base.py", line 369, in execute
output = self.handle(*args, **options)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\core\management\base.py", line 83, in wrapped
res = handle_func(*args, **kwargs)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\core\management\commands\migrate.py", line 231, in handle
post_migrate_state = executor.migrate(
File "C:\Users\USER\Envs\startup\lib\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 "C:\Users\USER\Envs\startup\lib\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 "C:\Users\USER\Envs\startup\lib\site-packages\django\db\migrations\executor.py", line 245, in apply_migration
state = migration.apply(state, schema_editor)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\migrations\migration.py", line 124, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\migrations\operations\fields.py", line 249, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\sqlite3\schema.py", line 138, in alter_field
super().alter_field(model, old_field, new_field, strict=strict)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\base\schema.py", line 564, in alter_field
self._alter_field(model, old_field, new_field, old_type, new_type,
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\sqlite3\schema.py", line 360, in _alter_field
self._remake_table(model, alter_field=(old_field, new_field))
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\sqlite3\schema.py", line 283, in _remake_table
self.execute("INSERT INTO %s (%s) SELECT %s FROM %s" % (
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\base\schema.py", line 142, in execute
cursor.execute(sql, params)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\utils.py", line 100, in execute
return super().execute(sql, params)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\utils.py", line 68, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
return executor(sql, params, many, context)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "C:\Users\USER\Envs\startup\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: new__startup_home_mates.user_id
If you need to see more code please let me know:)

You may added a primary key / id with your models later, but previous database does not have it.
If you add new features to models, add default='something', or null=True,blank=True as arguments. So that old database won't need the unique constraints/value

I suspect that your problem is with your OnetoOneField with unique set to True. You should change this to a ForeignKey (and don't set Unique = True). This is so that users can have more than one mate. That is if I have correctly understood your model setup and what you are trying to achieve.
Here is a good summary of the differences between OnetoOneField and ForeignKey:
What's the difference between django OneToOneField and ForeignKey?

Django- Change Username field to BigAutoField?

I'm designing an Application where username will be an AutoIntegerField and unique.
Here's my model.
class ModelA(models.Model):
username = models.BigAutoField(primary_key=True, db_index=False)
user_id = models.UUIDField(default=uuid.uuid4, unique=True,
editable=False)
Initially, I wanted user_id to be a primary_key, but I can't create an AutoField which is not primary_key. As a result, I'd to let go off user_id as primary_key and assigned username as the primary key.
Now, when I run the migrations, it throws an error saying,
django.db.utils.ProgrammingError: operator class "varchar_pattern_ops" does not accept data type bigint
Complete StackTrace:-
Applying users.0005_auto_20180626_0914...Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
psycopg2.ProgrammingError: operator class "varchar_pattern_ops" does not accept data type bigint
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
utility.execute()
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/core/management/__init__.py", line 356, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/core/management/base.py", line 283, in run_from_argv
self.execute(*args, **cmd_options)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/core/management/base.py", line 330, in execute
output = self.handle(*args, **options)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 204, in handle
fake_initial=fake_initial,
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/migrations/executor.py", line 115, in migrate
state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/migrations/executor.py", line 145, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
state = migration.apply(state, schema_editor)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/migrations/migration.py", line 129, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/migrations/operations/fields.py", line 216, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 515, in alter_field
old_db_params, new_db_params, strict)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/postgresql/schema.py", line 112, in _alter_field
new_db_params, strict,
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 684, in _alter_field
params,
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 120, in execute
cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/utils.py", line 80, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/utils/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: operator class "varchar_pattern_ops" does not accept data type bigint

I think the issue is that you still have an old index on your username field that clashes with the new type. The db_index=False argument has no effect because primary_key=True always generates an index.
You might be able to solve this by removing primary_key=True, creating a migration, and then re-adding it and creating another migration. Alternatively, you can do it by hand by dropping and re-creating the index. If you want to go down that path, consult this answer.
If your project is still in an early stage and you don't have any valuable data, you can take the easy way out and drop any tables related to your users app or even the complete database, delete all migrations in the users app and create them from scratch.

in my case I was connecting django to postgres at localhost pgadmin
first deleted all the migrations except default one and also in the pycache
then just run python manage.py makemigrations and python manage.py migrate in your terminal

OperationalError during django migration postgres on large tables

Sometimes during migrations in django on big tables (>50 millions rows) i receive the following error:
Traceback:
Traceback (most recent call last):
File "src/audit/manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 363, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 355, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 283, in run_from_argv
self.execute(*args, **cmd_options)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 330, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/commands/migrate.py", line 204, in handle
fake_initial=fake_initial,
File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/executor.py", line 115, in migrate
state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/executor.py", line 145, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/executor.py", line 244, in apply_migration
state = migration.apply(state, schema_editor)
File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/migration.py", line 129, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/operations/fields.py", line 86, in database_forwards
field,
File "/usr/local/lib/python3.5/dist-packages/django/db/backends/base/schema.py", line 439, in add_field
self.execute(sql)
File "/usr/local/lib/python3.5/dist-packages/django/db/backends/base/schema.py", line 120, in execute
cursor.execute(sql, params)
File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 80, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python3.5/dist-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/usr/local/lib/python3.5/dist-packages/django/utils/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
django.db.utils.OperationalError: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
Can you please give me advice - which postgres settings i should change in order to solve this issue?
I try set statement_timeout = 0, idle_in_transaction_session_timeout = 0 with no result.
Migration:
class Migration(migrations.Migration):
dependencies = [
('core', '0028_auto_'),
]
operations = [
migrations.AddField(
model_name='risk',
name='test3',
field=models.CharField(default='testme', max_length=50),
),
]
SQL:
BEGIN;
--
-- Add field test3 to risk
--
ALTER TABLE "core_risk" ADD COLUMN "test3" varchar(50) DEFAULT 'testme' NOT NULL;
ALTER TABLE "core_risk" ALTER COLUMN "test3" DROP DEFAULT;
COMMIT;