首先我创建一个简单的表
import threading
from sqlalchemy import create_engine
from sqlalchemy import Column, Integer, Float, String, Date, DateTime, Boolean, select
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.pool import SingletonThreadPool
from sqlalchemy.orm import scoped_session
from sqlalchemy.orm import sessionmaker
inven_schema = {'__tablename__' : 'inventory',
'item_no' : Column(Integer, primary_key=True, autoincrement=True),
'desc' : Column(String(255), nullable=False),
'volume' : Column(Integer, nullable=False)
}
Base = declarative_base()
# Dynamically create Inventory for ORM
Inventory = type('Inventory', (Base,), inven_schema)
some_inventory = [{'item_no' : 0, 'desc' : 'toy crane', 'volume' : 12},
{'item_no' : 1, 'desc' : 'puddle jumper', 'volume' : 2},
{'item_no' : 2, 'desc' : 'pet snake', 'volume' : 1},
{'item_no' : 3, 'desc' : 'bowling ball', 'volume' : 4},
{'item_no' : 4, 'desc' : 'spinning top', 'volume' : 3},
{'item_no' : 5, 'desc' : 'pumpkin', 'volume' : 2}]
但是如果会话和插入在不同的线程上,我就不能让它工作。这是我的尝试,它抛出:
^{pr2}$我尝试过在线程调用中创建会话,以及其他一些变体。我应该如何修改以下方法?在
def insert_inventory(inventory, session):
inventory_ = [Inventory(**inven) for inven in inventory]
session.add_all(inventory_)
session.commit()
def results(session):
q = select([Inventory.item_no]).distinct(Inventory.item_no)
distinct_items = session.execute(q).fetchall()
print('{!r}'.format(distinct_items))
def demo2():
engine = create_engine('sqlite://')
conn = engine.connect()
Base.metadata.create_all(conn.engine)
session_factory = sessionmaker(bind=conn.engine)
Session = scoped_session(session_factory)
session = Session()
thread_0 = threading.Thread(target=insert_inventory, args=(some_inventory, session))
thread_0.start()
session.close()
results(session)
我无法
add()
或add_all()
级别。如果engine()
是用其他参数创建的,则以下操作有效。在我相信它是序列化对sqlite3db表的调用,这对sqlite来说并不理想,但却是必需的。在
相关问题 更多 >
编程相关推荐