作为我的数据科学课程的一部分，我们必须将python程序连接到我们创建的数据库中。我们得到了PG-Admin，SQL-Alchemy和psycopg2。但是，每当尝试建立与数据库的连接时，都会出现错误，我不知道如何解决。 我的代码如下：
import psycopg2 #provides drivers for PostgreSQL
import numpy as np
import json #required to access json file
import pandas as pd
from sqlalchemy import create_engine
with open('configTemplate.json') as f:
conf = json.load(f)
print(type(conf))
print("Name of database is: ",conf['database'])
print("Name of user is: ",conf['user'])
conn_str ='postgresql://%s:%s@localhost:5432/%s'%(conf["user"], conf["passw"],conf["database"])
engine = create_engine(conn_str)
with engine.connect() as conn, conn.begin():
data = pd.read_sql_table('test', conn)
这将创建以下输出：
<class 'dict'>
Name of database is: datamining
Name of user is: db_user
和
---------------------------------------------------------------------------
OperationalError Traceback (most recent call last)
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\base.py in _wrap_pool_connect(self, fn, connection)
2337 try:
-> 2338 return fn()
2339 except dialect.dbapi.Error as e:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in unique_connection(self)
303 """
--> 304 return _ConnectionFairy._checkout(self)
305
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in _checkout(cls, pool, threadconns, fairy)
777 if not fairy:
--> 778 fairy = _ConnectionRecord.checkout(pool)
779
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in checkout(cls, pool)
494 def checkout(cls, pool):
--> 495 rec = pool._do_get()
496 try:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\impl.py in _do_get(self)
139 with util.safe_reraise():
--> 140 self._dec_overflow()
141 else:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\langhelpers.py in __exit__(self, type_, value, traceback)
68 compat.raise_(
---> 69 exc_value, with_traceback=exc_tb,
70 )
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\compat.py in raise_(***failed resolving arguments***)
181 try:
--> 182 raise exception
183 finally:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\impl.py in _do_get(self)
136 try:
--> 137 return self._create_connection()
138 except:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in _create_connection(self)
308
--> 309 return _ConnectionRecord(self)
310
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in __init__(self, pool, connect)
439 if connect:
--> 440 self.__connect(first_connect_check=True)
441 self.finalize_callback = deque()
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in __connect(self, first_connect_check)
660 with util.safe_reraise():
--> 661 pool.logger.debug("Error on connect(): %s", e)
662 else:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\langhelpers.py in __exit__(self, type_, value, traceback)
68 compat.raise_(
---> 69 exc_value, with_traceback=exc_tb,
70 )
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\compat.py in raise_(***failed resolving arguments***)
181 try:
--> 182 raise exception
183 finally:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in __connect(self, first_connect_check)
655 self.starttime = time.time()
--> 656 connection = pool._invoke_creator(self)
657 pool.logger.debug("Created new connection %r", connection)
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\strategies.py in connect(connection_record)
113 return connection
--> 114 return dialect.connect(*cargs, **cparams)
115
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\default.py in connect(self, *cargs, **cparams)
492 # inherits the docstring from interfaces.Dialect.connect
--> 493 return self.dbapi.connect(*cargs, **cparams)
494
~\AppData\Roaming\Python\Python37\site-packages\psycopg2\__init__.py in connect(dsn, connection_factory, cursor_factory, **kwargs)
126 dsn = _ext.make_dsn(dsn, **kwargs)
--> 127 conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
128 if cursor_factory is not None:
OperationalError:
The above exception was the direct cause of the following exception:
OperationalError Traceback (most recent call last)
<ipython-input-4-388c442643cd> in <module>
1 conn_str ='postgresql://%s:%s@localhost:5432/%s'%(conf["user"], conf["passw"],conf["database"])
2 engine = create_engine(conn_str)
----> 3 with engine.connect() as conn, conn.begin():
4 data = pd.read_sql_table('test', conn)
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\base.py in connect(self, **kwargs)
2263 """
2264
-> 2265 return self._connection_cls(self, **kwargs)
2266
2267 @util.deprecated(
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\base.py in __init__(self, engine, connection, close_with_result, _branch_from, _execution_options, _dispatch, _has_events)
102 connection
103 if connection is not None
--> 104 else engine.raw_connection()
105 )
106 self.__transaction = None
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\base.py in raw_connection(self, _connection)
2370 """
2371 return self._wrap_pool_connect(
-> 2372 self.pool.unique_connection, _connection
2373 )
2374
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\base.py in _wrap_pool_connect(self, fn, connection)
2340 if connection is None:
2341 Connection._handle_dbapi_exception_noconnection(
-> 2342 e, dialect, self
2343 )
2344 else:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\base.py in _handle_dbapi_exception_noconnection(cls, e, dialect, engine)
1582 elif should_wrap:
1583 util.raise_(
-> 1584 sqlalchemy_exception, with_traceback=exc_info[2], from_=e
1585 )
1586 else:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\compat.py in raise_(***failed resolving arguments***)
180
181 try:
--> 182 raise exception
183 finally:
184 # credit to
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\base.py in _wrap_pool_connect(self, fn, connection)
2336 dialect = self.dialect
2337 try:
-> 2338 return fn()
2339 except dialect.dbapi.Error as e:
2340 if connection is None:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in unique_connection(self)
302
303 """
--> 304 return _ConnectionFairy._checkout(self)
305
306 def _create_connection(self):
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in _checkout(cls, pool, threadconns, fairy)
776 def _checkout(cls, pool, threadconns=None, fairy=None):
777 if not fairy:
--> 778 fairy = _ConnectionRecord.checkout(pool)
779
780 fairy._pool = pool
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in checkout(cls, pool)
493 @classmethod
494 def checkout(cls, pool):
--> 495 rec = pool._do_get()
496 try:
497 dbapi_connection = rec.get_connection()
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\impl.py in _do_get(self)
138 except:
139 with util.safe_reraise():
--> 140 self._dec_overflow()
141 else:
142 return self._do_get()
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\langhelpers.py in __exit__(self, type_, value, traceback)
67 if not self.warn_only:
68 compat.raise_(
---> 69 exc_value, with_traceback=exc_tb,
70 )
71 else:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\compat.py in raise_(***failed resolving arguments***)
180
181 try:
--> 182 raise exception
183 finally:
184 # credit to
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\impl.py in _do_get(self)
135 if self._inc_overflow():
136 try:
--> 137 return self._create_connection()
138 except:
139 with util.safe_reraise():
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in _create_connection(self)
307 """Called by subclasses to create a new ConnectionRecord."""
308
--> 309 return _ConnectionRecord(self)
310
311 def _invalidate(self, connection, exception=None, _checkin=True):
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in __init__(self, pool, connect)
438 self.__pool = pool
439 if connect:
--> 440 self.__connect(first_connect_check=True)
441 self.finalize_callback = deque()
442
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in __connect(self, first_connect_check)
659 except Exception as e:
660 with util.safe_reraise():
--> 661 pool.logger.debug("Error on connect(): %s", e)
662 else:
663 if first_connect_check:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\langhelpers.py in __exit__(self, type_, value, traceback)
67 if not self.warn_only:
68 compat.raise_(
---> 69 exc_value, with_traceback=exc_tb,
70 )
71 else:
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\util\compat.py in raise_(***failed resolving arguments***)
180
181 try:
--> 182 raise exception
183 finally:
184 # credit to
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\pool\base.py in __connect(self, first_connect_check)
654 try:
655 self.starttime = time.time()
--> 656 connection = pool._invoke_creator(self)
657 pool.logger.debug("Created new connection %r", connection)
658 self.connection = connection
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\strategies.py in connect(connection_record)
112 if connection is not None:
113 return connection
--> 114 return dialect.connect(*cargs, **cparams)
115
116 creator = pop_kwarg("creator", connect)
~\.conda\envs\DataScience\lib\site-packages\sqlalchemy\engine\default.py in connect(self, *cargs, **cparams)
491 def connect(self, *cargs, **cparams):
492 # inherits the docstring from interfaces.Dialect.connect
--> 493 return self.dbapi.connect(*cargs, **cparams)
494
495 def create_connect_args(self, url):
~\AppData\Roaming\Python\Python37\site-packages\psycopg2\__init__.py in connect(dsn, connection_factory, cursor_factory, **kwargs)
125
126 dsn = _ext.make_dsn(dsn, **kwargs)
--> 127 conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
128 if cursor_factory is not None:
129 conn.cursor_factory = cursor_factory
OperationalError: (psycopg2.OperationalError)
(Background on this error at: http://sqlalche.me/e/13/e3q8)
问题似乎与psycopg2-module有关，但是我似乎找不到解决方法。我尝试将其安装在单独的环境中，我使用了pip安装以及conda安装，还尝试安装二进制文件。似乎什么也没用，我的教授也帮不了我。
我正在使用Anaconda和Jupyter Notebooks，并且正在使用Windows。任何帮助将不胜感激，因为我的课程确实需要它。非常感谢！