Python 3 索引超出范围错误

Question

我在 postgresql 服务器中执行了以下代码。

from datetime import datetime

now = str(datetime.now(None))
procurementinsertqueries=[]
priceupdatequeries = []
inventoryupdatequeries=[]
ptrcode = -1
debugcode=""

try:
    unpbatches=[]
    query = "select distinct(fk_procurementbatch_code) from newprocurementlist"
    proclistresult = plpy.execute(query)

    for rec in proclistresult:
        unpbatches.append(rec["fk_procurementbatch_code"])

    for batchcode in unpbatches:
        ptrcode=-1
        query = "select procurementtransaction_code from procurement where fk_procurementbatch_code="+str(batchcode)+" order by procurementtransaction_code desc limit 1"
        ptrcoderesult = plpy.execute(query)

        if len(ptrcoderesult)==0:
            ptrcode=0
        else:
            ptrcode=ptrcoderesult[0]["procurementtransaction_code"]

        query = "select * from newprocurementlist where fk_procurementbatch_code="+str(batchcode)
        newproclistresult = plpy.execute(query)

        for r in newproclistresult: 
            ptrcode+=1
            _bcode = str(r["fk_procurementbatch_code"])
            _pref = str(r["fk_product_ref"])
            _up = str(r["unitsprocured"])
            _tp = str(r["totalprice"])
            _cp = str(r["costprice"])
            _sp = str(r["sellingprice"])
            _mrp = str(r["mrp"])
            _trcode = str(ptrcode)
            procurementinsertqueries.append("insert into procurement values("+_bcode+","+_pref+","+_up+","+_tp+","+_cp+","+_sp+","+_mrp+","+_trcode+")")
            priceupdatequeries.append("insert into productpriceupdatelist values("+_pref+")")
            _aunits = 0.0
            _newunits = 0.0
            query="select unitsavailable from inventory where fk_product_ref="+_pref
            au = -1
            au = plpy.execute(query)
            _aunits=float(au[0]["unitsavailable"])
            _newunits = _aunits+float(r["unitsprocured"])
            inventoryupdatequeries.append("update inventory set unitsavailable="+str(_newunits)+" where fk_product_ref="+_pref)
            debugcode+="--Completed--"
        debugcode+="---Loop completed---"   

except Exception as e:
    plpy.execute("insert into log values(\'"+now+"\')")
    raise plpy.error("Error generating insert queries-->"+str(e)+"Debug is "+debugcode)

try:
    with plpy.subtransaction():
        for qry in procurementinsertqueries:
            plpy.execute(qry)
        for qry in priceupdatequeries:
            plpy.execute(qry)   
        for qry in inventoryupdatequeries:
            plpy.execute(qry)
except Exception as e:
    plpy.execute("insert into log values(\'"+now+": Error executing insert queries\')")
    raise plpy.error("Error executing procurement updates. There could be loss of data.Please review database error log. -->"+str(e))

try:
    plpy.execute("delete from newprocurementlist")
except Exception as e:
    plpy.execute("insert into log values(\'"+now+": Error deleting new procurement list table after successful updates\')")
    raise plpy.error("Error deleting completed procurement list. There could be duplication of data. Review error log file-->"+str(e))

try:
    plpy.execute("select product_price_update_process()")
except Exception as e:
    raise plpy.error("Error updating prices. "+str(e))

问题是我收到“索引超出范围”错误。附件是我得到的错误。

ERROR:  plpy.Error: Error generating insert queries-->list index out of rangeDebug is --Completed--
CONTEXT:  Traceback (most recent call last):
  PL/Python function "procurementlist_process", line 61, in <module>
    raise plpy.error("Error generating insert queries-->"+str(e)+"Debug is "+debugcode)
PL/Python function "procurementlist_process"

当我使用 for 循环时，我无法理解索引为何超出范围。

请帮忙!!

编辑:请注意我表中的测试数据，unpbatches 中的项目数仅为 1。

Answer 1

也许 au 在这里是一个空列表:

    au = plpy.execute(query)
    _aunits=float(au[0]["unitsavailable"])

au是查询的结果集吗？也许查询没有返回任何行。

---

一般来说，你应该按照jknupp在评论中的建议进行修改

raise plpy.error("Error generating insert queries-->"+str(e)+"Debug is "+debugcode)

只是

raise

查看原始回溯和发生错误的确切行。