Python，Oracle_cx，使用查询结果作为参数列表进入循环插入语句

Question

过去，我编写了一个pl / sql脚本，该脚本以一个表名和一个列名（表示源）作为参数，然后分析表中的所有列以提供有用的计数。

我目前正在自学python，并且正在以可以针对其他sql数据库（而不仅仅是oracle）执行的方式重写pl / sql脚本。所以我是Python的新手。我正在对Udemy上的无聊的东西进行自动化。目前，我不关心sql注入，因为我只是在学习Python语言。我省略了创建表语句以减少我要粘贴的代码量。

该脚本在循环的第一遍插入正确的记录，但是它没有启动第二个循环。这是IDLE输出，然后是代码。

================================================ RESTART: C:\Users\nathan\Documents\_work\_data_profiling_script\profiling_python_tester.py ================================================
('ETL_INS_DTM',)
insert into PROFILING_NWS6_PRT
            select 'PROFILING_NWS6', 'ETL_INS_DTM', SRCRECNO, count(*), null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null
            from PROFILING_NWS6
            group by SRCRECNO
            order by 1,2,3
executed
committed
**Traceback (most recent call last):
  File "C:\Users\nathan\Documents\_work\_data_profiling_script\profiling_python_tester.py", line 39, in <module>
    for row in cursor:
cx_Oracle.InterfaceError: not a query**

---

import cx_Oracle
conn = cx_Oracle.connect("system", "XXXX", "localhost/xe")
cursor = conn.cursor()

## parameter declaration
##########################################################################

# These 2 parameters populated by user
v_st = 'PROFILING_NWS6' # Source Table - table in which we are profiling the data
v_srcno = 'SRCRECNO' # Source Number - numeric column in v_st that identifies the source system

# These 3 parameters automatically populated
v_prt = v_st + '_PRT' # Profile Report Table - table name we want our report created as
v_log = v_st + '_LOG' # Log Table - script logging goes here, used for monitoring and debugging
v_top = v_st + '_TOP' # Top Table - temporary table to hold top 5 counts


# write script that populates Profile Report Table with rows for each source/column combination from source table
# these are required to join to when updating analysis fields
##########################################################################

sql = "Select column_name from user_tab_columns where table_name = '"+ v_st + "' and column_name <> '" + v_srcno + "'"
cursor.execute(sql)
for row in cursor:
    print(row)
    sql =   """insert into {x_prt}
            select '{x_st}', '{x_row}', {x_srcno}, count(*), null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null
            from {x_st}
            group by {x_srcno}
            order by 1,2,3""".format(x_prt = v_prt, x_srcno = v_srcno, x_st = v_st, x_row = row[0])
    print(sql)
    cursor.execute(sql)
    print('executed')
    cursor.execute('commit')
    print('committed')


#close connections
##########################################################################
cursor.close()
conn.close()

Answer 1

for row in cursor:中的光标仍在使用，直到循环完成。在循环内执行cursor.execute(sql)时，它将更改cursor对象。因此，在第二个循环中，要迭代的cursor项目是循环内commit的光标。解决方案是在循环内创建或使用其他光标对象。

cursor = conn.cursor()         # original cursor, as above
insert_cursor = conn.cursor()  # new one for insert
sql = "Select column_name from user_tab_columns where table_name "  # etc

for row in cursor.execute(sql):
    print(row)
    sql =   """second sql""".format(...)
    print(sql)
    insert_cursor.execute(sql)
    print('executed')
    insert_cursor.execute('commit')
    print('committed')

cursor.close()
insert_cursor.close()
conn.close()

此外，for row in cursor:应为for row in cursor.fetchall():。要不就for row in cur.execute(sql):。