以下代码抛出“ sqlalchemy.exc.CompileError:未使用的列名:_id”。
User = Table('users', metadata,
Column('id', Integer, primary_key=True),
Column('score', Integer)
)
values = [
{'score': 2, '_id': 1},
{'score': 3, '_id': 3}
]
query = User.update().where(User.c.id == bindparam('_id')).values(score=bindparam('score'))
await db.execute_many(query, values)
db
是databases。Database
的实例。注意,我必须使用名称“ _id”,因为SQLalchemy说“ id”是保留的。
除了更新每行的个性化之外还有其他解决方案吗?
[Database.execute_many()
调用Connection.execute_many()
,将您的查询分解为单独的单个查询(values
中的每个元素一个),这是方法(source):]]
async def execute_many( self, query: typing.Union[ClauseElement, str], values: list ) -> None: queries = [self._build_query(query, values_set) for values_set in values] async with self._query_lock: await self._connection.execute_many(queries)
注意,它调用了
_build_query()
方法(source):
@staticmethod def _build_query( query: typing.Union[ClauseElement, str], values: dict = None ) -> ClauseElement: if isinstance(query, str): query = text(query) return query.bindparams(**values) if values is not None else query elif values: return query.values(**values) return query
由于您没有传递
str
查询,而是传递值,因此控件进入elif values:
条件处理,其中将各个值的dict解压缩到查询的.values()
方法中(即Update.values()
)。从本质上讲,这使得查询正在尝试编译它:
Update.values()
该第二个值子句会导致使用新的绑定参数进行新的更新,这些绑定参数正在尝试为
query = ( User.update() .where(User.c.id == bindparam("_id")) .values(score=bindparam("score")) .values(score=2, _id=1) )
和score
设置值。这将导致查询编译失败,因为表上没有_id
列。
所以重现错误的MCVE确实是这样:
_id
哪个加薪:
from sqlalchemy.dialects import postgresql User.update().values(score=2, _id=1).compile(dialect=postgresql.dialect())
总而言之,您通过将绑定参数传递到
Traceback (most recent call last): File ".\main.py", line 31, in <module> User.update().values(score=2, _id=1).compile(dialect=postgresql.dialect()) File "<string>", line 1, in <lambda> File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\elements.py", line 462, in compile return self._compiler(dialect, bind=bind, **kw) File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\elements.py", line 468, in _compiler return dialect.statement_compiler(dialect, self, **kw) File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\compiler.py", line 571, in __init__ Compiled.__init__(self, dialect, statement, **kwargs) File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\compiler.py", line 319, in __init__ self.string = self.process(self.statement, **compile_kwargs) File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\compiler.py", line 350, in process return obj._compiler_dispatch(self, **kwargs) File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\visitors.py", line 92, in _compiler_dispatch return meth(self, **kw) File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\compiler.py", line 2569, in visit_update self, update_stmt, crud.ISUPDATE, **kw File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\crud.py", line 62, in _setup_crud_params return _get_crud_params(compiler, stmt, **kw) File "C:\Users\peter\Documents\git\stackoverflow\58668615-sqalchemy-update-bindparam-primary-key\.venv\lib\site-packages\sqlalchemy\sql\crud.py", line 177, in _get_crud_params % (", ".join("%s" % c for c in check)) sqlalchemy.exc.CompileError: Unconsumed column names: _id
和Update.where()
来构建查询。然后,您将该查询和您的值传递到Update.values()
,在其中它们将您的值列表中的各个元素解压缩到查询中的第二个Database.execute_many()
调用中,该调用将替换为试图为Update.values()
设置值的查询列不存在。
除了更新每行的个性化之外还有其他解决方案吗?
使用SQLalchemy引擎和查询时,查询工作很好:
_id
否则,应该以字符串形式将查询发送到
# using a sqlalchemy engine engine.execute(query, values)
,因为这意味着查询将在Database.execute_many()
方法的if isinstance(query, str):
部分中处理,这将避免进行第二次_build_query()
调用在查询中:
.values()