SQLAlchemy: MariaDB のデータを削除 (Delete)

プログラム

maria_delete.py

#! /usr/bin/python
#
#	maria_delete.py
#					Sep/03/2024
#
# ----------------------------------------------------------------
import sys
from time import localtime,strftime
#
from sqlalchemy import create_engine
from sqlalchemy.orm import declarative_base
#from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, DateTime, Sequence
from sqlalchemy.orm import scoped_session, sessionmaker
#
# ----------------------------------------------------------------
sys.stderr.write("*** 開始 ***\n")
#
key_in = sys.argv[1]
print(key_in)
#
host='localhost'
data_base = 'city'
user ='scott'
password = 'tiger123'
db_url = "mysql://" + user + ":" + password + "@" + host + "/" + data_base
engine = create_engine(db_url)
#
Base = declarative_base()
class City(Base):
	__tablename__ = "cities"
	id = Column(String(16), primary_key=True)
	name = Column(String(255))
	population = Column(Integer)
	date_mod = Column(DateTime)
#
session = scoped_session(
	sessionmaker(autocommit=False, autoflush=False, bind=engine)
)
#
city_a = session.query(City).filter_by(id=key_in).first()
if city_a != None:
	session.delete(city_a)
	sys.stderr.write(key_in + " is deleted.\n")
session.commit()
#
sys.stderr.write("*** 終了 ***\n")
#
# ----------------------------------------------------------------

実行コマンド

./maria_delete.py t3325

確認したバージョン

$ python --version
Python 3.11.3