Question

from sqlalchemy import Column, Integer, String, MetaData, Table, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

#table columns describing
params = dict( lid       = Column(Integer, primary_key=True),
               cab_name  = Column(String))

table_name = dict(__tablename__ = "table")


def cab_init(self, **kwargs ):
    for k,v in kwargs.items():
        setattr(self, k, v)

methods = dict( __init__ = cab_init )

cab_item = type("cab_item", (declarative_base(),), dict ( methods.items()
                                           + params.items()
                                           + table_name.items() ) )


engine = create_engine('sqlite:///:memory:', echo=False)
meta = MetaData()

table = Table('table', meta,                              #(*1)
           Column('lid', Integer,primary_key=True),
           Column('cab_name', String),
           )
#table = Table(name = 'table', metadata = meta, args = params.values()) #(*2)
meta.create_all(engine)

session = sessionmaker(engine)()
session.merge(cab_item(lid=10, cab_name="blah"))

session.commit()

（* 1）工作正常，（* 2）产生错误

sqlalchemy.exc.OperationalError：（OperationalError）没有这样的表：表u＆＃39; SELECT＆＃34; table＆＃34; .lid AS table_lid，＆＃34; table＆＃34; .cab_name AS table_cab_name \ nFROM＆＃34; table＆＃34; \ nWHERE＆＃34; table＆＃34; .lid =？＆＃39; （10）

为什么？

Answer 1

我找到了解决方案

params被宣布错误。正确的方法是

params2 = (Column('lid', Integer, primary_key=True), Column('cab_name',String))
致电Table

table = Table('table', meta, *params2)

表构造函数很奇怪

1 个答案: