我有一个如下定义的表，可以使用这个模式从数据库中读取并创建丢失的表。在如何向数据库中添加一行时遇到了困难：
from sqlalchemy import create_engine, select, table, inspect, MetaData
from sqlalchemy import Column, Integer, String, LargeBinary, Text,
ForeignKey, Table, Boolean, JSON
from sqlalchemy.orm import sessionmaker, registry, relationship
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
engine = create_engine(STR_CONN) #, echo=True)
metadata = MetaData(engine)
Session = sessionmaker(bind=engine)
session = Session()
@mapper_registry.mapped
@dataclass
class UsersTbl():
__table__ = Table(
"users",
metadata,
Column("email_address", String, primary_key=True),
Column("saved_state", JSON),
)
email_address: str = None
saved_state: str = None
lookupcolumn: Column = __table__.columns['email_address']
metadata.create_all(engine)
如果需要，创建丢失的表
sql = select(table.__table__).where(table.lookupcolumn == lookupkey)
with engine.connect() as conn:
dbdata = conn.execute(sql).all()
按预期返回一行
但是当我尝试添加一行如下
entry = UsersTbl("blah@blah.com", "{}")
session.add(entry)
session.commit()
我收到一个错误
"quot"ProgrammingError:(psycopg2.errors.UndefinedTable(对表"的FROM子句项的引用无效；用户"；第1行：。。。T INTO用户(email_address，saved_state(值(users.emai。。。^提示：有一个表"的条目；用户"；，但不能从查询的这一部分引用它。
[SQL:插入到用户(email_address，saved_state(值(users.email_aaddress，%(saved_state(s(返回用户.email_address][参数：｛‘save_state’："｛｝"｝](此错误的背景信息位于：https://sqlalche.me/e/14/f405)"quot">
令人沮丧的是，我可以使用以下方法来发布数据，但似乎无法自动创建上面缺失的表或检索数据：(感谢您的帮助！
class User2(Base):
__tablename__ = 'users'
email_address = Column("email_address", String, primary_key=True)
saved_state = Column("saved_state", String)
def __init__(self, email_address=None, saved_state=None):
self.email_address = email_address
self.saved_state = saved_state
entry = User2("blah@blah.com2", "{}")
session.add(entry)
session.commit()
如有任何帮助，将不胜感激
stmt = insert(Tables.UsersTbl).values(('spongebob2d', "Spongebob Squarepants"))
with engine.connect() as conn:
result = conn.execute(stmt)
成功了：(