python + SQLAlchemy: deleting with the Session object

Question

I can't quite figure this out: I'd like to delete all the records from a table on a matching query. Kind of like this.

engine = sqlalchemy.create_engine(string)
meta = MetaData(bind=engine)
meta.reflect(bind=engine, schema='myschema')

Base = automap_base(metadata=meta)
Base.prepare(engine, reflect=True)
Classes = Base.classes

Session = sessionmaker(bind=engine)
session = Session()

session.delete(plays.record_id == '123')

But that isn't working. What's the idea here? Error I get is:

error in parsing record ID 020087: Class 'sqlalchemy.sql.elements.BinaryExpression' is not mapped

question from:https://stackoverflow.com/questions/26643727/python-sqlalchemy-deleting-with-the-session-object

Answer 1

In SQL Alchemy you are deleting Objects that you get with a query from the database. This you can do in 2 Ways:

Deleting with query (will issue just one DELETE statement):

session.query(User).filter(User.id==7).delete()
session.commit()

Deleting object instance returned by a query (will issue 2 statements: first SELECT, then DELETE):

obj=session.query(User).filter(User.id==7).first()
session.delete(obj)
session.commit()