Python 到 Netezza JDBC 连接在 Mac 上给出 SQL .execute 错误

问题描述

所以我正在编写一个 Python 脚本来检索 Netezza 表数据库的计数。但是，我收到以下错误。请告诉我如何解决这个问题。

  File "/Users/skulk00/PycharmProjects/NZ_RS_Validator/table_details_thread_pool.py",line 175,in <module>
    result = result_netezza_cursor.execute('SELECT COUNT(1) FROM STORE')
AttributeError: 'Connection' object has no attribute 'execute'

这是我的连接代码：

NETEZZA_JAR_LOC = os.path.join('/Users/skulk00/Connection Softwares/nzjdbc.jar')
NETEZZA_PP = ('username','password','xx.6.8.xx','dbname','netezza','org.netezza.Driver','5480')

class Connector:
    """Create Database connection."""

    def __init__(self,db_name):
        self.db_name = db_name
        self.all_db = {
            'netezza_pp': NETEZZA_PP,'netezza_prod': NETEZZA_PROD,}
        if self.db_name not in self.all_db:
            raise ValueError(f'Available database choices are {tuple(self.all_db.keys())}')

    def _get_cxn_string(self,user,password,host,dbname,dialect,driver,port):
        if 'netezza' in self.db_name:
            db_string = f'jdbc:{dialect}://{host}:{port}/{dbname}'
        return db_string

    def cursor(self):
        db_name = self.db_name
        db_creds = self.all_db[db_name]
        db_string = self._get_cxn_string(*db_creds)

        print(db_name)
        print(db_creds)
        print(db_string)

        if 'netezza' in db_name:
            cxn = jaydebeapi.connect('org.netezza.Driver',db_string,{'user': db_creds[0],'password': db_creds[1]},jars=NETEZZA_JAR_LOC)
        return cxn

这是我的主要功能代码：

result_netezza_connector = Connector('netezza_pp')
result_netezza_cursor = result_netezza_connector.cursor()
result = result_netezza_cursor.execute('SELECT COUNT(1) FROM STORE')
print(result)

解决方法

我建议使用 Python native nzpy 驱动程序进行 Python 脚本与 Netezza 的交互

import nzpy

conn = nzpy.connect(user="...",password="...",host='...',port=5480,database="...")

with conn.cursor() as cursor:
    cursor.execute(...)

更详细的例子可以参考these samples

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回到 JDBC 问题 - 问题是您从 jayedebeapi.Connection 方法返回一个 Connector.cursor()，而不是一个游标。

result_netezza_connector = Connector('netezza_pp')
with result_netezza_connector.cursor().cursor() as result_netezza_cursor:
    result_netezza_cursor.execute('SELECT COUNT(1) FROM STORE')
    print(result_netezza_cursor.fetchall())

# a better option to display is using pandas
import pandas
df = pandas.read_sql('SELECT COUNT(1) from STORE',result_netezza_connect)
df 
# will print tabular and you can use the dataframe for further
# processing

.cursor().cursor() 令人困惑，我建议将 Connection.cursor() 方法重命名为 Connection.connection()。这将使它更具可读性-

with result_netezza_connector.connection().cursor() as ...

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这是一个 Python 笔记本中相同的最小示例