[Python] How to delete all rows matching a condition using SqlModel

The documentation of SqlModel about DELETE action: https://sqlmodel.tiangolo.com/tutorial/delete/

shows how to delete a single line using the functions

• .one() - If only a single record is expected

or

• .first() - to get the 1st line from multiple lines found.

def delete_heroes():
with Session(engine) as session:
statement = select(Hero).where(Hero.name == "Spider-Youngster")
results = session.exec(statement)
hero = results.one()
print("Hero: ", hero)

session.delete(hero)
session.commit()


But how can I delete all the lines matching the condition? I tried using the .all() function

def delete_heroes():
with Session(engine) as session:
statement = select(Hero).where(Hero.name == "Spider-Youngster")
results = session.exec(statement)
hero = results.all()
print("Hero: ", hero)

session.delete(hero)
session.commit()


But all I get is an error: sqlalchemy.orm.exc.UnmappedInstanceError: Class 'builtins.list' is not mapped


My solution uses a loop to iterate over multiple lines, delete each line and commit at the end.

def delete_heroes():
with Session(engine) as session:
statement = select(Hero).where(Hero.name == "Spider-Youngster")
results = session.exec(statement)
hero = results.all()
print("Hero: ", hero)

for result in results:
session.delete(result)

session.commit()


Is there a way to do this without the loop?

Continue reading...