从 Python 写入 SQL Server

【问题标题】：Writing to SQL Server from Python从 Python 写入 SQL Server
【发布时间】：2020-03-28 10:26:09
【问题描述】：

这是我能举出的最小的例子，MRE

我正在尝试执行以下操作：

  • 使用pyodbc，从 SQL Server 实例中读取（完成）
  • 然后，打印该数据以进行验证（完成）
  • 然后，获取该数据，并将其插入到新表中（或覆盖该表，如果存在）FAILURE

代码如下：

import pyodbc
import pandas as pd
import sqlalchemy as sa

sqlConn = pyodbc.connect(
    "DRIVER={SQL Server};"
    "SERVER=servername;"
    "DATABASE=dbname;"
    "Trusted_Connection=yes;"
)

sql = """
SELECT TOP (1000) [PART]
      ,[STEP]
      ,[COMPLETIONTIME]
  FROM [dbname].[dbo].[STEPS]
"""

engine = sa.create_engine('mssql+pyodbc://servername/dbname')


df = pd.read_sql(sql, sqlConn)

df.to_sql(name = 'Test', con = engine, if_exists = 'replace', index = False)
sqlConn.commit()
sqlConn.close()

我收到以下错误信息：

  File "WiP.py", line 26, in <module>
    df.to_sql(name = 'Test', con = engine, if_exists = 'replace', index = False)
  File "C:\Python367-64\lib\site-packages\pandas\core\generic.py", line 2712, in to_sql
    method=method,
  File "C:\Python367-64\lib\site-packages\pandas\io\sql.py", line 518, in to_sql
    method=method,
  File "C:\Python367-64\lib\site-packages\pandas\io\sql.py", line 1319, in to_sql
    table.create()
  File "C:\Python367-64\lib\site-packages\pandas\io\sql.py", line 641, in create
    if self.exists():
  File "C:\Python367-64\lib\site-packages\pandas\io\sql.py", line 628, in exists
    return self.pd_sql.has_table(self.name, self.schema)
  File "C:\Python367-64\lib\site-packages\pandas\io\sql.py", line 1344, in has_table
    self.connectable.dialect.has_table, name, schema or self.meta.schema
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2162, in run_callable
    with self._contextual_connect() as conn:
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2242, in _contextual_connect
    self._wrap_pool_connect(self.pool.connect, None),
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2280, in _wrap_pool_connect
    e, dialect, self
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 1547, in _handle_dbapi_exception_noconnection
    util.raise_from_cause(sqlalchemy_exception, exc_info)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\compat.py", line 398, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\compat.py", line 152, in reraise
    raise value.with_traceback(tb)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2276, in _wrap_pool_connect
    return fn()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 363, in connect
    return _ConnectionFairy._checkout(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 760, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 492, in checkout
    rec = pool._do_get()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\impl.py", line 139, in _do_get
    self._dec_overflow()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\langhelpers.py", line 68, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\compat.py", line 153, in reraise
    raise value
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\impl.py", line 136, in _do_get
    return self._create_connection()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 308, in _create_connection
    return _ConnectionRecord(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 437, in __init__
    self.__connect(first_connect_check=True)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 639, in __connect
    connection = pool._invoke_creator(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\strategies.py", line 114, in connect
    return dialect.connect(*cargs, **cparams)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\default.py", line 482, in connect
    return self.dbapi.connect(*cargs, **cparams)
sqlalchemy.exc.InterfaceError: (pyodbc.InterfaceError) ('IM002', '[IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0) (SQLDriverConnect)')
(Background on this error at: http://sqlalche.me/e/rvf5)

我查了on this site，得到了以下信息：

与数据库相关的错误引发的异常 操作，不一定在程序员的控制下， 例如发生意外断开连接，数据源名称不是 发现，无法处理事务，内存分配错误 在处理等过程中发生。

我也咨询过：

我也尝试将df.to_sql(name = 'Test', con = engine, if_exists = 'replace', index = False) 切换到df.to_sql(name = 'Test', con = sqlConn, if_exists = 'replace', index = False)，但得到了完全相同的错误。

我做错了什么？如何从 Pandas 数据框中写入新表（或覆盖现有表）？

更新

似乎连接失败。以下：

import pyodbc
import pandas as pd
import sqlalchemy as sa
from sqlalchemy import create_engine

sqlConn = pyodbc.connect(
    "DRIVER={SQL Server};"
    "SERVER=servername;"
    "DATABASE=dbname;"
    "Trusted_Connection=yes;"
)

sql = """
SELECT TOP (1000) [ORDR_PART_NO]
      ,[OROP_ID]
      ,[COMPLETIONTIME]
  FROM [dbname].[dbo].[OpsLookup]
"""
engine = sa.create_engine('mssql+pyodbc://servername/dbname')

cnxn = engine.connect()
result = cnxn.execute("SELECT TOP (1000) * FROM [dbname].[dbo].[STEPS]")
for row in result:
    print(row)
cnxn.close()

产量：

C:\Python367-64\lib\site-packages\sqlalchemy\connectors\pyodbc.py:79: SAWarning: No driver name specified; this is expected by PyODBC when using DSN-less connections
  "No driver name specified; "
Traceback (most recent call last):
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2276, in _wrap_pool_connect
    return fn()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 303, in unique_connection
    return _ConnectionFairy._checkout(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 760, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 492, in checkout
    rec = pool._do_get()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\impl.py", line 139, in _do_get
    self._dec_overflow()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\langhelpers.py", line 68, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\compat.py", line 153, in reraise
    raise value
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\impl.py", line 136, in _do_get
    return self._create_connection()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 308, in _create_connection
    return _ConnectionRecord(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 437, in __init__
    self.__connect(first_connect_check=True)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 639, in __connect
    connection = pool._invoke_creator(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\strategies.py", line 114, in connect
    return dialect.connect(*cargs, **cparams)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\default.py", line 482, in connect
    return self.dbapi.connect(*cargs, **cparams)
pyodbc.InterfaceError: ('IM002', '[IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0) (SQLDriverConnect)')

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

Traceback (most recent call last):
  File "WiP.py", line 21, in <module>
    cnxn = engine.connect()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2209, in connect
    return self._connection_cls(self, **kwargs)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 103, in __init__
    else engine.raw_connection()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2307, in raw_connection
    self.pool.unique_connection, _connection
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2280, in _wrap_pool_connect
    e, dialect, self
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 1547, in _handle_dbapi_exception_noconnection
    util.raise_from_cause(sqlalchemy_exception, exc_info)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\compat.py", line 398, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\compat.py", line 152, in reraise
    raise value.with_traceback(tb)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\base.py", line 2276, in _wrap_pool_connect
    return fn()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 303, in unique_connection
    return _ConnectionFairy._checkout(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 760, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 492, in checkout
    rec = pool._do_get()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\impl.py", line 139, in _do_get
    self._dec_overflow()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\langhelpers.py", line 68, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\util\compat.py", line 153, in reraise
    raise value
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\impl.py", line 136, in _do_get
    return self._create_connection()
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 308, in _create_connection
    return _ConnectionRecord(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 437, in __init__
    self.__connect(first_connect_check=True)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\pool\base.py", line 639, in __connect
    connection = pool._invoke_creator(self)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\strategies.py", line 114, in connect
    return dialect.connect(*cargs, **cparams)
  File "C:\Python367-64\lib\site-packages\sqlalchemy\engine\default.py", line 482, in connect
    return self.dbapi.connect(*cargs, **cparams)
sqlalchemy.exc.InterfaceError: (pyodbc.InterfaceError) ('IM002', '[IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0) (SQLDriverConnect)')
(Background on this error at: http://sqlalche.me/e/rvf5)

【问题讨论】：

标签： python sql-server pandas sqlalchemy pyodbc


【解决方案1】：

engine = sa.create_engine('mssql+pyodbc://servername/dbname')

需要改成

engine = sa.create_engine('mssql+pyodbc://servername/dbname?trusted_connection=yes&amp;driver=ODBC Driver 13 for SQL Server')

每个人：https://docs.sqlalchemy.org/en/13/dialects/mssql.html#hostname-connections

【讨论】：

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