cx_Oracle 'ORA-01843: 不是有效的月份' 与 Unicode 参数

Question

我有以下内容：（使用ipython）

In [30]: con = cx_Oracle.connect('refill_test02/******@MYDB')

In [31]: cur = con.cursor()

In [32]: cur.execute("ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS' NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF'")

In [33]: cur.execute("select to_date(:0), to_timestamp(:1) from dual", ['2013-03-12', '2013-03-12 08:22:31.332144'])
Out[33]: <__builtin__.OracleCursor on <cx_Oracle.Connection to refill_test02@MYDB>>

In [34]: cur.fetchall()
Out[34]: 
[(datetime.datetime(2013, 3, 12, 0, 0),
  datetime.datetime(2013, 3, 12, 8, 22, 31, 332144))]

In [35]: cur.execute("select to_date(:0), to_timestamp(:1) from dual", [u'2013-03-12', '2013-03-12 08:22:31.332144'])
Out[35]: <__builtin__.OracleCursor on <cx_Oracle.Connection to refill_test02@MYDB>>

In [36]: cur.fetchall()
Out[36]: 
[(datetime.datetime(2013, 3, 12, 0, 0),
  datetime.datetime(2013, 3, 12, 8, 22, 31, 332144))]

In [37]: cur.execute("select to_date(:0), to_timestamp(:1) from dual", [u'2013-03-12', u'2013-03-12 08:22:31.332144'])
---------------------------------------------------------------------------
DatabaseError                             Traceback (most recent call last)
/home/xxxxx/<ipython-input-37-8af80e5fc40c> in <module>()
----> 1 cur.execute("select to_date(:0), to_timestamp(:1) from dual", [u'2013-03-12', u'2013-03-12 08:22:31.332144'])

DatabaseError: ORA-01843: not a valid month


In [38]: cur.execute("select to_date(:0), to_timestamp(:1) from dual", [u'2013-03-12', '2013-03-12 08:22:31.332144'])
---------------------------------------------------------------------------
DatabaseError                             Traceback (most recent call last)
/home/xxxx/<ipython-input-38-bc628f006aa3> in <module>()
----> 1 cur.execute("select to_date(:0), to_timestamp(:1) from dual", [u'2013-03-12', '2013-03-12 08:22:31.332144'])

DatabaseError: ORA-01843: not a valid month


In [39]: cur.execute("ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS' NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF'")

In [40]: cur.execute("select to_date(:0), to_timestamp(:1) from dual", [u'2013-03-12', '2013-03-12 08:22:31.332144'])
Out[40]: <__builtin__.OracleCursor on <cx_Oracle.Connection to refill_test02@MYDB>>

In [41]: cur.fetchall()
Out[41]: 
[(datetime.datetime(2013, 3, 12, 0, 0),
  datetime.datetime(2013, 3, 12, 8, 22, 31, 332144))]

出于某种原因，我无法使用unicode字符串作为时间戳参数（IN[37]）。更奇怪的是，在我这样做之后，我需要重置会话的NLS格式，才能再次用普通字符串正常工作。

我使用的是：

Cx_Oracle 5.1.2

python 2.7.3

Oracle 10.2.0.1.0

有什么想法吗？

感谢你花时间阅读这个。

Answer 1

我在使用RHEL 5、Cx_Oracle 5.1、Python 2.4.3和Oracle 11.2.0.3.0时，无法重现这个错误。你有没有尝试用格式字符串来配合to_date和to_timestamp这两个函数呢？

https://gist.github.com/fclrc/5435561

#! /bin/python
import cx_Oracle
import platform

print ("Python version: " + platform.python_version())
print ("cx_Oracle version: " + cx_Oracle.version)
print ("Oracle client: " + str(cx_Oracle.clientversion()).replace(', ','.'))

connection = cx_Oracle.connect('user/pass@tns')
cursor = connection.cursor()
#
# Option with format strings
#
cursor.execute("""select to_date(:arg1,'yyyy-mm-dd'), to_timestamp(:arg2,'yyyy-mm-dd hh24.mi.ss.ff') from dual""", arg1=u'2013-03-12', arg2=u'2013-03-12 08:22:31.332144')
#
# Option without format strings
#
#cursor.execute("ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS' NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF'")
#cursor.execute("select to_date(:0), to_timestamp(:1) from dual", [u'2013-03-12', u'2013-03-12 08:22:31.332144'])

mydate = cursor.fetchall()
print mydate
cursor.close()
connection.close()

Answer 2

根据jtiai的问题描述，我想出了以下解决办法——在调用任何有问题的SQL语句之前（比如oracle 10.5.0.2和11.2.0.1，cx_oracle 5.1.2），重新设置NLS_DATE_FORMAT/NLS_TIMESTAMP_FORMAT：

cursor.execute(
     "ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS'"
     " NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF'")

# do execute ...
cursor.execute(query, params)

Answer 3

其实这是Oracle 10.5.0.2和11.2.0.1版本中的一个错误。

这个错误可以通过以下步骤重现：

在会话中设置NLS_TIMESTAMP_FORMAT。

使用Unicode数据进行任何隐式或显式的TO_DATE转换。

接下来，使用Unicode数据进行隐式或显式的TO_TIMESTAMP转换时，会导致时间戳格式内部重置。

之后的所有TO_TIMESTAMP操作都会失败，而时间戳的TO_CHAR输出也会变得无效。

下面是测试这个行为的代码：

ALTER SESSION SET NLS_TERRITORY = 'AMERICA';
ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS' NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF';

REM --- WORKS:
SELECT TO_TIMESTAMP('2013-06-24 18:15:10.312') FROM DUAL;

REM --- WORKS:
SELECT TO_DATE('2013-06-24 18:15:10') FROM DUAL;

REM --- WORKS:
SELECT TO_TIMESTAMP('2013-06-24 18:15:10.312') FROM DUAL;

REM --- WORKS:
SELECT TO_TIMESTAMP(x) FROM (SELECT CAST('2013-06-24 18:15:10.312' AS NVARCHAR2(30)) AS X FROM DUAL);

REM --- WORKS:
SELECT TO_DATE(x) FROM (SELECT CAST('2013-06-24 18:15:10' AS NVARCHAR2(30)) AS X FROM DUAL);

REM --- WORKS:
SELECT TO_TIMESTAMP('2013-06-24 18:15:10.312') FROM DUAL;

REM !!! FAILS!
SELECT TO_TIMESTAMP(x) FROM (SELECT CAST('2013-06-24 18:15:10.312' AS NVARCHAR2(30)) AS X FROM DUAL);

REM !!! FAILS!
SELECT TO_TIMESTAMP('2013-06-24 18:15:10.312') FROM DUAL;

REM --- WORKS:
SELECT TO_DATE('2013-06-24 18:15:10') FROM DUAL;