python+sqlalchemy用法示例，注意makedsn挺关键

python+sqlalchemy用法示例，注意配置makedsn挺关键，否则就会报各种错误，当然版本版本挺重要

import cx_Oracle
from sqlalchemy import create_engine
import os,time
os.environ['NLS_LANG'] = 'SIMPLIFIED CHINESE_CHINA.UTF8'
import pandas as pd

ip = '127.0.0.1'
port = '1521'
uname = 'tcmp' # 用户名
pwd = '1234' # 密码
tnsname = 'orcl' # 实例名

dsnStr = cx_Oracle.makedsn(ip, port, service_name=tnsname)
connect_str = "oracle://%s:%s@%s" %(uname, pwd, dsnStr)
engine = create_engine(connect_str)
sql = "SELECT *  FROM T_GNLK_TEMP where rownum<=500000"
df=pd.read_sql(sql,con=engine)
print(df)