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pandas - Teradata 插入错误：ValueError：DataFrame 的真值不明确

问题描述

我正在尝试将 pandas 数据框插入 Teradata 并遇到此错误。与 Teradata 的连接正在工作，因为我能够一次插入一条记录相同的数据。请帮忙。

import pandas as pd
import teradata as td

Car_Sales = pd.DataFrame([
    {"Sale_Dt":"2019-10-01", "Brand":"Mercedes","Sale_Type":"New","Dealer_Type":"Urban","SalesVol":"5"},
    {"Sale_Dt":"2019-10-02", "Brand":"BMW","Sale_Type":"Used","Dealer_Type":"Sub-Urban","SalesVol":"3"},
    ])

udaExec = td.UdaExec()
with udaExec.connect(method="odbc",DSN = "dsn1",driver = 'Teradata Database ODBC Driver 16.20') as session:
#session.execute("INSERT INTO db.tbl_Cars (Sale_Dt,Brand,Sale_Type,Dealer_Type,SalesVol) VALUES (?,?,?,?,?)",("2019-10-01","Mercedes","New","Urban",5))
query2 = "INSERT INTO db.tbl_Cars"    
session.execute(query2,Car_Sales,batch=True)

错误：ValueError：DataFrame 的真值不明确。使用 a.empty、a.bool()、a.item()、a.any() 或 a.all()。

标签： pandasteradata

解决方案

这可能是因为您直接将 DataFrame 传递给execute. 此外，对于批量插入，文档说您必须使用executemany. 一个小例子——

session.executemany("""INSERT INTO employee (id, firstName, lastName, dob) 
                       VALUES (?, ?, ?, ?)""", 
                    ((1,"James", "Kirk", "2233-03-22"), 
                     (2,"Jean-Luc", "Picard", "2305-07-13")), 
                    batch=True)

所以，在你的情况下，它会是

with udaExec.connect(method="odbc",DSN = "dsn1",driver = 'Teradata Database ODBC Driver 16.20') as session:
    #session.execute("INSERT INTO db.tbl_Cars (Sale_Dt,Brand,Sale_Type,Dealer_Type,SalesVol) VALUES (?,?,?,?,?)",("2019-10-01","Mercedes","New","Urban",5))

    #No. of ? must be equal to number of fields in each tuple 
    query2 = "INSERT INTO db.tbl_Cars VALUES (?, ?, ...)" 

    data = tuple(tuple(x) for x in Car_Sales.values)
    session.executemany(query2, data, batch=True)

有关更多信息，请查看teradata的文档

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