为什么sqlalchemy postgres引擎连接会自动提交？

问：

由于某种原因，引擎连接会自动提交，这是不希望的。我想明确提交。这是我的代码（它逐字重复官方教程）：

from sqlalchemy import Table, Column, ForeignKey, Integer, String
from sqlalchemy.orm import relationship
from sqlalchemy.orm import registry
from sqlalchemy import create_engine
from sqlalchemy import ForeignKey

engine = create_engine('postgresql+psycopg2://user:password@localhost:5432/test_db', echo=True)

mapper_registry = registry()
Base = mapper_registry.generate_base()

user_table = Table(
    "user_account",
    mapper_registry.metadata,
    Column("id", Integer, primary_key=True),
    Column("name", String(30)),
    Column("fullname", String),
)

mapper_registry.metadata.create_all(engine)

stmt = insert(user_table).values(name="spongebob", fullname="Spongebob Squarepants")
print(stmt)
    
with engine.connect() as conn:
    result = conn.execute(stmt)
    # conn.commit() 

即使没有提交，我的日志也是：

INSERT INTO user_account (name, fullname) VALUES (:name, :fullname)
2023-02-09 16:12:05,033 INFO sqlalchemy.engine.Engine INSERT INTO user_account (name, fullname) VALUES (%(name)s, %(fullname)s) RETURNING user_account.id
2023-02-09 16:12:05,034 INFO sqlalchemy.engine.Engine [generated in 0.00123s] {'name': 'spongebob', 'fullname': 'Spongebob Squarepants'}
2023-02-09 16:12:05,037 INFO sqlalchemy.engine.Engine COMMIT

并且新对象出现在数据库中。 我试图设置，但没有成功conn.execution_options(isolation_level="SERIALIZABLE")create_engine(...).execution_options(isolation_level="SERIALIZABLE")

但是，当我设置为 时，日志略有不同（因此我确信isolation_level选项被正确解释）：isolation_level"AUTOCOMMIT"

INSERT INTO user_account (name, fullname) VALUES (:name, :fullname)
2023-02-09 16:17:35,889 INFO sqlalchemy.engine.Engine INSERT INTO user_account (name, fullname) VALUES (%(name)s, %(fullname)s) RETURNING user_account.id
2023-02-09 16:17:35,890 INFO sqlalchemy.engine.Engine [generated in 0.00132s] {'name': 'spongebob', 'fullname': 'Spongebob Squarepants'}
2023-02-09 16:17:35,893 INFO sqlalchemy.engine.Engine COMMIT using DBAPI connection.commit(), DBAPI should ignore due to autocommit mode

sqlalchemy.__version__
'1.4.46'

这种行为的原因是什么？

我有什么不明白的？

我错过了什么？

谢谢

重要更新

正如@snakecharmerb所指出的，它按预期工作（这是与文档的唯一显着区别）。fututre=true

engine = create_engine('...url', echo=True, future=True**)

因此，此标志会更改自动提交行为。

INSERT INTO user_account (name, fullname) VALUES (:name, :fullname)
2023-02-09 17:42:08,499 INFO sqlalchemy.engine.Engine BEGIN (implicit)
2023-02-09 17:42:08,499 INFO sqlalchemy.engine.Engine INSERT INTO user_account (name, fullname) VALUES (%(name)s, %(fullname)s) RETURNING user_account.id
2023-02-09 17:42:08,500 INFO sqlalchemy.engine.Engine [generated in 0.00085s] {'name': 'spongebob', 'fullname': 'Spongebob Squarepants'}
<sqlalchemy.engine.cursor.CursorResult object at 0x7fef30f76ac0>
2023-02-09 17:42:10,511 INFO sqlalchemy.engine.Engine ROLLBACK

它主要回答了我的问题，但我仍然很好奇我是否可以在没有 的情况下有类似的行为，因为我还不能打开它（对于我从事的项目）future=True