Graph/sqlalchemy

Package

sqlalchemy

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Updated4/30/2026

PageRank0.0008

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39 linked nodes

indiviual tests (at least with my config) can not share a single database connection pool or rather a single db engine unlike the FastAPI app instance — tests for my fastapi application that uses asynchronous posgtres connection. Tension: share a single database connection pool or rather a single db engine unlike the FastAPI app instance. Outcome: This will enforce a new db connection with every request creating a ton of overhead.

REQUIRESSolution

create a dedicated `test_db_session()` method that includes the engine disposal — use this one for your tests. Tension: You should never dispose the db engine in your `get_session()` method that is used by your backend application. Outcome: You can then use this `test_db_session()` in your tests by overrding the FastAPI dependencies.

REQUIRESRootCause

postgresql+asyncpg://{DB_USER}:{DB_PASSWD}@{DB_HOST}:5432/{DB_NAME}. Tension: as apparently this is not supported. Outcome: pass in the SSL mode.

REQUIRESSolution

postgresql+asyncpg. Tension: where you can pass in the SSL mode. Outcome: SQLALCHEMY_DATABASE_URI: str = URL.create( drivername="postgresql+asyncpg", username=DB_USER, password=DB_PASSWD, host=DB_HOST, port=5432, database=DB_NAME, query={ "ssl": "require" } ).

REQUIRESSolution

I'd like to use `AsyncSession.sync_session` — async def get_session() -> AsyncSession: session = SessionLocal(). Tension: the code below fails with error. Outcome: use `AsyncSession.sync_session` but the code below fails with error.

REQUIRESSolution

Use the db client itself and call self.db_client.session() inside the service

REQUIRESSolution

setting this event before you call `create_all` — before you call `create_all`. Outcome: connection.execute(CreateSchema('justsomeschema')).

REQUIRESSolution

you can use following — joined tables. Tension: Any other columns you need from joined tables.

REQUIRESSolution

doing the "join" logic in Python, rather than on the database — player.as_dict(). Tension: rather than having to do the join in Python itself. Outcome: base_data["scores"] = [score.as_dict() for score in player.scores].

REQUIRESSolution

Use `selectinload() `to eager-load the relationship — from sqlalchemy.orm import selectinload. Tension: lazy-loaded relationships like user_info.classes are being accessed in an async context.

REQUIRESSolution

you should be able to simplify that down using joins and avoids having subqueries — with Session(engine) as session. Outcome: final_query = session.query(TaskContent, User.username)\ .join( User, TaskContent.created_by == User.id )\ .join( CurrentTaskContent, CurrentTaskContent.identifier == TaskContent.identifier ).

REQUIRESRootCause

Inside Alembic's `env.py`, you can swap out the default engine with your Google Cloud custom engine — connect alembic to the Cloud SQL. Tension: As far as I know I should set the sqlalembic.url in alembic.ini file. Outcome: swap out the default engine with your Google Cloud custom engine from cloud-sql-python-connector.

REQUIRESSolution

Set expire_on_commit=False on the async_sessionmaker — after commit. Tension: Or use await session.refresh(obj, ["relationship_name"]) after commit. Or eagerly load all needed relationships BEFORE commit using selectinload() or joinedload(). Outcome: attributes retain their in-memory values after commit.

PERTAIN_TOProblem

String literals such as `toys:["ToyResponse"]`, this method still causes circular import errors. Tension: you are still importing the class to resolve the type. Outcome: doesnt work when a child import a parent.

PERTAIN_TOProblem

But none of them worked for me. — to create the schema and tables from my models during startup. Tension: I am not sure if that is the best way to do it, so any suggestions on that are welcome as well. Outcome: You should be able to hook in your schema creation before the metadata is all created.

PERTAIN_TOProblem

I would like to follow the same to connect alembic to the Cloud SQL — I connected my fastapi project to Cloud SQL by following this code. Tension: I did not document how to connect with google connector. Outcome: Is there a way?

OCCURS_INProblem

that will give me 3 levels deep of nodes in my json output — I have a many to many self referential relationship. Tension: is there a way to do that so it goes as many levels deep as needed until nodes = [] ? Outcome: Do I need to use something like marshmallow-sqlalchemy ?

IMPLEMENTATION_OFDomain

ORM

AFFECTSRootCause

Outcome: The trace really does have that much impact.

AFFECTSRootCause

async def get_db_session() -> AsyncSession.

AFFECTSRootCause

indiviual tests (at least with my config) can not share a single database connection pool or rather a single db engine unlike the FastAPI app instance — tests for my fastapi application that uses asynchronous posgtres connection. Tension: share a single database connection pool or rather a single db engine unlike the FastAPI app instance. Outcome: This will enforce a new db connection with every request creating a ton of overhead.

AFFECTSRootCause

the database operations (`db.commit`, `db.flush`) were all synchronous — When a route in FastAPI is listed as asynchronous (`async def`). Outcome: meaning the event loop is blocked until they are completed.

AFFECTSRootCause

Contextvars where added to the language so that concurrent Async tasks can "see" independent context information — The act of creating a concurrent task in asyncio, which FastAPI does for your before calling `main`. Tension: even if the tasks run the same functions.

AFFECTSRootCause

Conditional by default, will not attempt to recreate tables already present in the target database. Tension: SQLModel uses the SQLAlchemy library and builds on it. Outcome: This means that once created, SQLModel will not attempt to change the schema of your database tables.

AFFECTSRootCause

postgresql+asyncpg://{DB_USER}:{DB_PASSWD}@{DB_HOST}:5432/{DB_NAME}. Tension: as apparently this is not supported. Outcome: pass in the SSL mode.

AFFECTSRootCause

An async fixture for the SQLAlchemy engine was declared with scope="session", causing pytest-asyncio to create/use a different event loop than the one used by the test tasks, so Futures/Tasks were bound to different loops.

AFFECTSRootCause

Pydantic is when it tries to construct the class objects causing a circular import. — SQLAlchemy doesn't attempt to process the type annotations at run time. Tension: but Pydantic is when it tries to construct the class objects. Outcome: causing a circular import.

AFFECTSRootCause

the `TYPE_CHECK` boolean must be checked at every place where the circular import types are being used. Tension: which results in an undefined error when accessing the type. Outcome: code inside if TYPE_CHECKING: is not executed at runtime.

AFFECTSRootCause

calling self.session_factory() returns a method object instead of a context manager

AFFECTSRootCause

hook in your schema creation before the metadata is all created — before you call `create_all`. Outcome: setting this event before you call `create_all`.

AFFECTSRootCause

the answer provided there does not work — convert a SqlAlchemy Join Query to JSON.

AFFECTSRootCause

lazy-loaded relationships like user_info.classes are being accessed in an async context — async SQLAlchemy on Strawberry GraphQL. Tension: can't call await_only() here. Outcome: which is not allowed.

AFFECTSRootCause

having subqueries — using joins and avoids having subqueries. Outcome: filter( (CurrentTaskContent.identifier != None), or_(TaskContent.due_date == _due_date, _due_date is None) ).

AFFECTSRootCause

Inside Alembic's `env.py`, you can swap out the default engine with your Google Cloud custom engine — connect alembic to the Cloud SQL. Tension: As far as I know I should set the sqlalembic.url in alembic.ini file. Outcome: swap out the default engine with your Google Cloud custom engine from cloud-sql-python-connector.

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