Category : sqlalchemy

I have some python code that I am trying to use to read uncommitted from my database in parallel using sqlalchemy and modin. I have tried calling the function as: df = pd.read_sql("select * from my_table", uri_string, params={‘isolation_level’: ‘READ UNCOMMITTED’}). However, I am seeing the generated queries submitted without an isolation level to my database. ..

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I have a session_helper.py that has a single function: @contextmanager def get_session(): """Helper method that yields a new DB session, and closes it when it goes out of scope. Use as: with get_session() as session: my_repo = MyRepository(session) my_repo.create() … """ session = SessionLocal() try: yield session finally: session.close() SessionLocal is defined in another file: ..

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Context I have three tables, Users, Subreddits, and Keywords. The idea is that users can monitor multiple subreddits, and subreddits can monitor multiple keywords. Since one user can monitor multiple subreddits, and one subreddit can have multiple users monitoring it, I would like to have a many-to-many relationship between Users and Subreddits. On the same ..

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I followed this example to get a Versioned mixin class, which generates companion _history tables for each ORM class its mixed into. class Foo(Versioned, Base): _tablename__ = "foo" id = Column(Integer, primary_key=True) whatever = Column(String) Effect is: new column generated Foo.version new DB table generated foo_history any time an instance of Foo is changed, its ..

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So i need to query some objects from the database, but i want given value of the attribute to be retrieved when there are multiple matching values of this attributes in the database and if not i’d like to receive null value. session.query( Stuff.uuid, Stuff.website, ) .group_by( Stuff.uuid, Stuff.website, ) .having( ( (func.count(Stuff.website) >= needed_row_count) ..

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