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问SQLAlchemy - sqlalchemy.exc.StatementError：(builtins.TypeError)序列项0:预期的str实例，元组找到
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Stack Overflow用户

提问于 2022-08-03 12:36:41

回答 1查看 85关注 0票数 0

我正在尝试使用Blockonomics API将BTC支付并入我的WEB应用程序，尽管我在根据以下模型创建新发票时遇到了问题：

class Product(Base):
    __tablename__ = 'product'
    id          = Column(Integer,      primary_key=True)
    title       = Column(String(128),  nullable=False)
    description = Column(String(1024), nullable=False)
    price       = Column(Float,        nullable=False)
    thumbnail   = Column(LargeBinary,  nullable=False)

    def __init__(self, title, description, price, thumbnail):
        self.title       = title
        self.description = description
        self.price       = price
        self.thumbnail   = thumbnail

    def __repr__(self):
        return '<%r>' % (self.title) 

class Invoice(Base):
    __tablename__ = 'btc_invoice'
    STATUS_CHOICES         = ((-1, "Not Started"), (0, 'Unconfirmed'), (1, "Partially Confirmed"), (2, "Confirmed"))
    id                     = Column(Integer,      primary_key=True)
    product_id             = Column(Integer,      ForeignKey('product.id'))
    order_id               = Column(String(250))
    address                = Column(String(250),  nullable=True)
    btcvalue               = Column(Integer,      nullable=True)
    received               = Column(Integer,      nullable=True)  
    txid                   = Column(String(250),  nullable=True)
    rbf                    = Column(Integer,      nullable=True)
    created_at             = Column(DateTime,     default=datetime.now())
    status                 = Column(Enum(STATUS_CHOICES),default=-1)
    
    # New instance instantiation procedure
    def __init__(self, product_id, order_id, address,  btcvalue, status=null, received=null, txid=null, rbf=null):
        self.product_id   = product_id
        self.order_id  = order_id
        self.address   = address
        self.btcvalue  = btcvalue
        self.status    = status
        self.received  = received
        self.txid      = txid
        self.rbf       = rbf

    def __repr__(self):
        return '<%r>' % (self.address)

下面是我的控制器中的一个函数，它会抛出一个错误，我不明白为什么：

def checkout(mockup, category, language, product_title, front=None, back=None):
    if (language not in languages):
        language = app_language
    
    product = Product.query.filter_by(title=product_title).first()
    customer_item_id = front.split('_')[0]

    url      = os.getenv("BLOCKONOMICS_URL")
    headers  = {"Authorization": "Bearer " + os.getenv("API_KEY"), 'X-BLOCKONOMICS-VERSION': '1'}
    # Get BitCoin address from Blockonomics API (response) in order to perform address
    response = requests.post(url, headers=headers)

    if response.status_code == 200:
        address = response.json()['address']
        bits    = exchanged_rate(product.price)
        order_id = uuid.uuid1()
        
        invoice = Invoice(product_id=product.id, order_id=str(order_id), address=address, btcvalue=bits*1e8)
        
        Base.metadata.create_all(bind=engine)
        BTC_INVOICE_TABLE = Base.metadata.tables['btc_invoice']
        
        stmt = (
            insert(BTC_INVOICE_TABLE).values(product_id=invoice.product_id, order_id=invoice.order_id, address=invoice.address, btcvalue=int(invoice.btcvalue))
        )
        compiled = stmt.compile()
        
        with engine.connect() as conn:
            result = conn.execute(stmt)
            conn.commit()
        
        return redirect(url_for('payment.track_invoice',invoice_id=order_id, language=language, **languages[language]))

实际的堆栈跟踪是：

Traceback (most recent call last):
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/sql/sqltypes.py", line 1625, in _db_value_for_elem
    return self._valid_lookup[elem]
KeyError: -1

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1720, in _execute_context
    dialect, self, conn, execution_options, *args, **kw
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/default.py", line 1074, in _init_compiled
    for key in positiontup
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/default.py", line 1074, in <listcomp>
    for key in positiontup
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/sql/sqltypes.py", line 1773, in process
    value = self._db_value_for_elem(value)
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/sql/sqltypes.py", line 1647, in _db_value_for_elem
    langhelpers.repr_tuple_names(self.enums),
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/util/langhelpers.py", line 1928, in repr_tuple_names
    return ", ".join(res)
TypeError: sequence item 0: expected str instance, tuple found

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/flask/app.py", line 2486, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/flask/app.py", line 2466, in wsgi_app
    response = self.handle_exception(e)
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/flask/app.py", line 2463, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/flask/app.py", line 1760, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/flask/app.py", line 1758, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/flask/app.py", line 1734, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/home/stefan/Desktop/Python/document-generator/app/mod_payment/controllers.py", line 91, in mockup_checkout
    result = conn.execute(stmt)
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1306, in execute
    return meth(self, multiparams, params, _EMPTY_EXECUTION_OPTS)
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/sql/elements.py", line 326, in _execute_on_connection
    self, multiparams, params, execution_options
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1508, in _execute_clauseelement
    cache_hit=cache_hit,
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1726, in _execute_context
    e, util.text_type(statement), parameters, None, None
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 2044, in _handle_dbapi_exception
    sqlalchemy_exception, with_traceback=exc_info[2], from_=e
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
    raise exception
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1720, in _execute_context
    dialect, self, conn, execution_options, *args, **kw
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/default.py", line 1074, in _init_compiled
    for key in positiontup
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/engine/default.py", line 1074, in <listcomp>
    for key in positiontup
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/sql/sqltypes.py", line 1773, in process
    value = self._db_value_for_elem(value)
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/sql/sqltypes.py", line 1647, in _db_value_for_elem
    langhelpers.repr_tuple_names(self.enums),
  File "/home/stefan/anaconda3/envs/flask-web-dev/lib/python3.7/site-packages/sqlalchemy/util/langhelpers.py", line 1928, in repr_tuple_names
    return ", ".join(res)
sqlalchemy.exc.StatementError: (builtins.TypeError) sequence item 0: expected str instance, tuple found
[SQL: INSERT INTO btc_invoice (product_id, order_id, address, btcvalue, created_at, status) VALUES (?, ?, ?, ?, ?, ?)]

我已尝试打印正在插入表中的所有值，以及它们的类型：

print(type(invoice.order_id))
print(type(invoice.product_id))
print(type(invoice.address))
print(type(invoice.btcvalue))

print("Statement -> ", stmt)
print("Compiled Parameters -> ", compiled.params)

<class 'str'>
<class 'int'>
<class 'str'>
<class 'float'>

Statement ->  INSERT INTO btc_invoice (product_id, order_id, address, btcvalue, created_at, status) VALUES (:product_id, :order_id, :address, :btcvalue, :created_at, :status)

Compiled Parameters ->  {'product_id': 1, 'order_id': 'a41c2be0-1327-11ed-914b-752bb22010b9', 'address': 'bc1qcynyjkg9qz5jswa2dm5ddqp2s3ryps7vk3uxst', 'btcvalue': 86540, 'created_at': None, 'status': None}

我在任何地方都看不见元组。SQLAlchemy是否在内部做一些我不知道的事情？我应该尝试普通的SQL，还是模型设计有什么问题？

python

flask

sqlalchemy

回答 1

Stack Overflow用户

发布于 2022-08-04 12:54:52

错误很可能来自status列:您不能通过传递Enum列列表来声明tuples列。

您可以做的是传递一个简单的列表并解压它：

STATUS_CHOICES = ["Not Started", "Unconfirmed", "Partially Confirmed", "Confirmed"]
status = Column(Enum(*STATUS_CHOICES), default="Not Started")

您应该做什么(says SQLAlchemy's final boss，而不是我)：使用python：

import enum

class StatusChoices(enum.Enum):
    not_started = -1
    unconfirmed = 0
    partially_confirmed = 1
    confirmed = 2

[...]

status = Column(Enum(StatusChoices), default=StatusChoices.not_started)

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/73221864

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