How to specify SQLAlchemy ForeignKey with specific schema name? - flask

Question

I have a Flask / Flask-User app that I am trying to convert from Python 3.6 to Flask / Flask-Security-Too under Python 3.10. There have been a lot of changes in the world since 3.6 and I am playing whack-a-mole trying to figure them out. In this particular case I am redoing the database tables since nothing from the old app needs to transfer to the new version. I am using the latest version of PyCharm and all of the latest versions of the libraries that Flask and Flask-Security-Too require.
Things to note: the target database is an MS SQL Server instance. There is an existing "database" that I must use and a specific "schema name" under which any tables I create must live.
I have successfully run flask db init and am trying to run the first flask db migrate but get the error:
(venv) PS C:\Users\me\PycharmProjects\MyProject\UserInterface\MyApp> flask db migrate
INFO [alembic.runtime.migration] Context impl MSSQLImpl.
INFO [alembic.runtime.migration] Will assume transactional DDL.
Traceback (most recent call last):
File "C:\Python310\lib\runpy.py", line 196, in _run_module_as_main
return _run_code(code, main_globals, None,
File "C:\Python310\lib\runpy.py", line 86, in _run_code
exec(code, run_globals)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\Scripts\flask.exe\__main__.py", line 7, in <module>
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\flask\cli.py", line 988, in main
cli.main()
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\flask\cli.py", line 579, in main
return super().main(*args, **kwargs)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\click\core.py", line 1055, in main
rv = self.invoke(ctx)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\click\core.py", line 1657, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\click\core.py", line 1657, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\click\core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\click\core.py", line 760, in invoke
return __callback(*args, **kwargs)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\click\decorators.py", line 26, in new_func
return f(get_current_context(), *args, **kwargs)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\flask\cli.py", line 427, in decorator
return __ctx.invoke(f, *args, **kwargs)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\click\core.py", line 760, in invoke
return __callback(*args, **kwargs)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\flask_migrate\cli.py", line 104, in migrate
_migrate(directory, message, sql, head, splice, branch_label, version_path,
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\flask_migrate\__init__.py", line 98, in wrapped
f(*args, **kwargs)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\flask_migrate\__init__.py", line 155, in migrate
command.revision(config, message, autogenerate=True, sql=sql,
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\command.py", line 229, in revision
script_directory.run_env()
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\script\base.py", line 569, in run_env
util.load_python_file(self.dir, "env.py")
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\util\pyfiles.py", line 94, in load_python_file
module = load_module_py(module_id, path)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\util\pyfiles.py", line 110, in load_module_py
spec.loader.exec_module(module) # type: ignore
File "<frozen importlib._bootstrap_external>", line 883, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\MyApp\migrations\env.py", line 104, in <module>
run_migrations_online()
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\MyApp\migrations\env.py", line 98, in run_migrations_online
context.run_migrations()
File "<string>", line 8, in run_migrations
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\runtime\environment.py", line 853, in run_migrations
self.get_context().run_migrations(**kw)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\runtime\migration.py", line 611, in run_migrations
for step in self._migrations_fn(heads, self):
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\command.py", line 205, in retrieve_migrations
revision_context.run_autogenerate(rev, context)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\autogenerate\api.py", line 526, in run_autogenerate
self._run_environment(rev, migration_context, True)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\autogenerate\api.py", line 573, in _run_environment
compare._populate_migration_script(
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\autogenerate\compare.py", line 55, in _populate_migration_script
_produce_net_changes(autogen_context, upgrade_ops)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\autogenerate\compare.py", line 89, in _produce_net_changes
comparators.dispatch("schema", autogen_context.dialect.name)(
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\util\langhelpers.py", line 267, in go
fn(*arg, **kw)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\autogenerate\compare.py", line 125, in _autogen_for_tables
[(table.schema, table.name) for table in autogen_context.sorted_tables]
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\sqlalchemy\util\langhelpers.py", line 1113, in __get__
obj.__dict__[self.__name__] = result = self.fget(obj)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\alembic\autogenerate\api.py", line 443, in sorted_tables
result.extend(m.sorted_tables)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\sqlalchemy\sql\schema.py", line 4697, in sorted_tables
return ddl.sort_tables(
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\sqlalchemy\sql\ddl.py", line 1213, in sort_tables
for (t, fkcs) in sort_tables_and_constraints(
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\sqlalchemy\sql\ddl.py", line 1291, in sort_tables_and_constraints
dependent_on = fkc.referred_table
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\sqlalchemy\sql\schema.py", line 3808, in referred_table
return self.elements[0].column.table
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\sqlalchemy\util\langhelpers.py", line 1113, in __get__
obj.__dict__[self.__name__] = result = self.fget(obj)
File "C:\Users\me\PycharmProjects\MyProject\UserInterface\venv\lib\site-packages\sqlalchemy\sql\schema.py", line 2507, in column
raise exc.NoReferencedTableError(
sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'roles_users.role_id' could not find table 'role' with which to generate a foreign key to target column 'id'
The User and Role models look like (pruned for length):
### USER
#
import uuid
from flask_security import UserMixin
from sqlalchemy import Column, Integer, String, Boolean, Unicode, DateTime, func
from sqlalchemy.orm import relationship, backref
from app.database import Base
class User(Base, UserMixin):
__tablename__ = 'user'
__table_args__ = {"schema": "ExistingSchemaName"}
id = Column(Integer,primary_key=True)
email = Column(Unicode(255),nullable=False,server_default=u'',unique=True)
...
# Flask-Security-Too fields
fs_uniquifier = Column(String(255), unique=True, nullable=False)
confirmed_at = Column(DateTime())
last_login_at = Column(DateTime())
current_login_at = Column(DateTime())
last_login_ip = Column(String(100))
current_login_ip = Column(String(100))
login_count = Column(Integer)
# Relationships
child_roles = relationship('Role',back_populates='parent_user')
import uuid
### ROLE
#
from flask_security import RoleMixin
from sqlalchemy import Column, Integer, String, ForeignKey
from sqlalchemy.orm import relationship
from app.database import Base
class Role(Base, RoleMixin):
__tablename__ = 'role'
__table_args__ = {"schema": "ExistingSchemaName"}
id = Column(Integer(),primary_key=True)
name = Column(String(64),nullable=False,server_default=u'',unique=True)
description = Column(String(255),nullable=False,server_default=u'')
# Have also tried adding schema name to ForeignKey without success, as in:
# user_id = Column(Integer,ForeignKey("ExistingSchemaName.user.id"))
user_id = Column(Integer,ForeignKey("user.id"))
parent_user = relationship("User",back_populates="child_roles")
The app.database.py file looks like:
from .settings import SQLALCHEMY_DATABASE_URI
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.ext.declarative import declarative_base
engine = create_engine(SQLALCHEMY_DATABASE_URI)
db = scoped_session(
sessionmaker(
autocommit=False,
autoflush=False,
bind=engine
)
)
Base = declarative_base()
Base.query = db.query_property()
def init_db():
import app.models
Base.metadata.create_all(bind=engine)
I think that I have set the one-to-many relationships correctly but I do not know what I am missing.