Question

我正在尝试在SQLite数据库中创建查询，但由于错误而无法创建会话：

name 'Session' is not defined

我在同一环境中安装了SQLAlchemy，Flask-SQLAlchemy和棉花糖。我也导入了sessionmaker库，但是我不知道错误的原因。

我阅读了the SQLAlchemy documentation关于会话的信息，但无法解决该错误。

我有以下代码：

from flask import Flask, request, jsonify
from sqlalchemy import Column, ForeignKey, Float, String, Integer
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship, sessionmaker
from sqlalchemy import create_engine
import os
import sys
import random

Base = declarative_base()

app = Flask(__name__)

class TransAccount(Base):
  __tablename__ = 'Transaccount'

  number_acc = Column(String(50), primary_key = True) 
  number_t = Column(Integer, primary_key = True)
  destiny = Column(String(50))
  type_t = Column(String(50))
  description_t = Column(String(100))

class BankAccount(Base):
  __tablename__ = 'Bankaccount'

  number_acc = Column(String(50), primary_key = True)
  owner_acc = Column(String(50))
  bank_name  = Column(String(50)) 
  amount_acc = Column(Float)
  description_acc = Column(String(100))
  transferbanks = relationship('TransferBank', secondary = TransAccount,   
  backref = 'BankAccount')

class TransferBank(Base):
__tablename__ = 'Transferbank'

number_t = Column(Integer, primary_key = True)
quantity_t = Column(Float)
owner_t = Column(String(50))
bankaccounts = relationship('BankAccount', secondary = TransAccount,  
backref = 'TransferBank')

engine = create_engine('sqlite:///clients.db')

sm = sessionmaker()

sm.configure(bind = engine)

session = Session()

Base.metadata.create_all(engine)

def transfer():
  if request.json['quantity_t'] <= 2000:

  if request.json['quantity_t'] > 0 and amount >  
  request.json['quantity_t']: 
    BankAccount.number_acc = request.json['source'] 
    Transaccount.destiny = request.json['destination']
    Transferbank.quantity_t = request.json['amount']
    BankAccount.amount_acc = BankAccount.amount_acc -  
    Transferbank.quantity_t - 2.5
    Transaccount.description_t = request.json['info']
    Transferbank.number_t = random.random()*1000
    Transaccount.number_t = Transferbank.number_t
    Transaccount.type_t = 'intra-bank'

    return jsonify({'message' : 'Transfer succeed!'})
  else:
    return jsonify({'message' : 'Account without enough funds'})  
  else:
    return jsonify({'message' : 'Transfer is higher than 2000€'}) 

def addfunds(account_id):

  account = session.query(BankAccount).filter(BankAccount.number_acc ==  
  account_id).one()
  if account:
    return jsonify({'message' : 'Account already exists'})
  else:
    BankAccount.amount_acc = request.json['amount']
    BankAccount.bank_name = request.json['src_bank']
    BankAccount.description_acc = request.json['info']
    session.close()

    return jsonify({'message' : 'Funds transferred successfully!'})

if __name__ == '__main__':
  app.run(debug = True)

如何创建会话？

谢谢

Answer 1

替换

engine = create_engine('sqlite:///clients.db')

sm = sessionmaker()

sm.configure(bind = engine)

session = Session()

打开

engine = create_engine('sqlite:///clients.db')
Session = sessionmaker(bind=engine)
session = Session()

会话未在SQLAlchemy中创建

1 个答案: