Error when using table name `user` with SQLAlchemy

[bystepii]

Environment

• Python version: 3.11.13
• SQLAlchemy version: 2.0.43
• pydynamodb version: 0.7.3

Description

When defining a model with the table name "user", pydynamodb fails when inserting a row. If the table name is changed (e.g., "usertable"), it works correctly.

Minimal Reproducible Example

import uuid, hashlib
from sqlmodel import SQLModel, Field, Session, select
from pydynamodb import sqlalchemy_dynamodb
from sqlalchemy.engine import create_engine


session = boto3.Session()
credentials = session.get_credentials()
aws_access_key_id = credentials.access_key
aws_secret_access_key = credentials.secret_key
region_name = session.region_name

conn_str = (
    "dynamodb://{aws_access_key_id}:{aws_secret_access_key}@dynamodb.{region_name}.amazonaws.com:443"
    + "?verify=false"
).format(
    aws_access_key_id=aws_access_key_id,
    aws_secret_access_key=aws_secret_access_key,
    region_name=region_name,
)
engine = create_engine(conn_str, echo=True)

class User(SQLModel):
    __table_args__ = {"extend_existing": True}
    id: str = Field(
        default_factory=lambda: uuid.uuid4().hex, primary_key=True, index=True
    )
    username: str = Field(unique=True)
    username_lower: str = Field(unique=True)
    password: str

def create_user(usn, pwd, user_id=None) -> bool:
    with Session(engine) as session:
        statement = select(User).where(User.username_lower == usn.lower())
        result = session.exec(statement).all()
        if result:
            print(f'User "{usn}" already exists')
            return False
        else:
            hashed_password = hashlib.sha256(pwd.encode()).hexdigest()
            user = User(
                id=user_id,
                username=usn,
                username_lower=usn.lower(),
                password=hashed_password,
            )
            session.add(user)
            session.commit()
            return True

create_user("admin", "admin")

Observed Behavior

DynamoDB returns an error:

2025-09-29 09:56:10,783 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2025-09-29 09:56:10,797 INFO sqlalchemy.engine.Engine SELECT id, username, username_lower, password 
FROM user 
WHERE username_lower = ?
2025-09-29 09:56:10,799 INFO sqlalchemy.engine.Engine [generated in 0.00230s] ('admin',)
/home/user/miniconda3/envs/test/lib/python3.11/site-packages/urllib3/connectionpool.py:1097: InsecureRequestWarning: Unverified HTTPS request is being made to host 'localhost'. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#tls-warnings
  warnings.warn(
2025-09-29 09:56:11,410 INFO sqlalchemy.engine.Engine INSERT INTO user VALUE {'id': ?, 'username': ?, 'username_lower': ?, 'password': ?}
2025-09-29 09:56:11,412 INFO sqlalchemy.engine.Engine [generated in 0.00235s] ('7fcb2a41b1ae4a94bcd37d9e80aa3aea', 'admin', 'admin', '8c6976e5b5410415bde908bd4dee15dfb167a9c873fc4bb8a81f6f2ab448a918')
/home/user/miniconda3/envs/test/lib/python3.11/site-packages/urllib3/connectionpool.py:1097: InsecureRequestWarning: Unverified HTTPS request is being made to host 'localhost'. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#tls-warnings
  warnings.warn(
Failed to execute statement.
Traceback (most recent call last):
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/pydynamodb/executor.py", line 85, in _dispatch_api_call
    response = retry_api_call(
               ^^^^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/pydynamodb/util.py", line 111, in retry_api_call
    return retry(func, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/tenacity/__init__.py", line 379, in __call__
    do = self.iter(retry_state=retry_state)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/tenacity/__init__.py", line 314, in iter
    return fut.result()
           ^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/concurrent/futures/_base.py", line 449, in result
    return self.__get_result()
           ^^^^^^^^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/concurrent/futures/_base.py", line 401, in __get_result
    raise self._exception
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/tenacity/__init__.py", line 382, in __call__
    result = fn(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/botocore/client.py", line 602, in _api_call
    return self._make_api_call(operation_name, kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/botocore/context.py", line 123, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/miniconda3/envs/test/lib/python3.11/site-packages/botocore/client.py", line 1078, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (ValidationException) when calling the ExecuteStatement operation: Statement wasn't well formed, can't be processed: Expected identifier for simple path
2025-09-29 09:56:11,614 INFO sqlalchemy.engine.Engine ROLLBACK

Expected Behavior

• Using user as a table name should work without errors.
• If user is a reserved word in PartiQL, pydynamodb should quote/escape it automatically.

[acanadil]

sus

[passren]

user as a reserved word should not be the problem because pydynamodb will add quotes for the table name automatically.
I didn't see the error when I tested with the same table structure, but I didn't use sqlmodel to do the test. Let me add sqlmodel to run another test case.

[passren]

@acanadil This issue was fixed by v0.7.4.

[bystepii]

@passren This error also happens using default as a name for a column. Seems default is also a reserved keyword in PartiQL. Could you fix it please?

[passren]

This will take much effort than I expected. It needs to rewrite part of DML syntax to accommodate reserved keyword in the columns or attributes. working on it...

[passren]

@bystepii Bumped the version to 0.7.5 and reserved keywords are supported for select and update statement.