Re: [cx-oracle-users] More than one type returned for a single column

[Anssi K. <aka...@gm...>]

Same problem when using a table, too:

import cx_Oracle
connection = cx_Oracle.connect('user/passwd@' +
                               cx_Oracle.makedsn('localhost', 1521, 'xe'))
cur = connection.cursor()
cur.execute("create table testt(col1 number, col2 number(5, 2))")
cur.execute("insert into testt values(1, 1)")
cur.execute("insert into testt values(1.1, 1.1)")
cur.execute("select col1, col2 from testt")
rows = list(cur.fetchall())
col1_vals = [row[0] for row in rows]
col2_vals = [row[1] for row in rows]
print col1_vals
print col2_vals
print set([type(v) for v in col1_vals])
print set([type(v) for v in col2_vals])

OUT:
[1, 1.1]
[1.0, 1.1]
set([<type 'float'>, <type 'int'>])
set([<type 'float'>])

Describe of the table tells the type of col1 is plain NUMBER.

 - Anssi


On Sun, Sep 30, 2012 at 5:51 PM, Dwayne King
<dw...@kr...>wrote:

> It *is* optional in oracle to supply the precision and scale when
> declaring a data type (in which case it will use the maximums for the
> type), so perhaps this is what happens.
>
> Can you do a describe on the table in question from sqlplus and show us?
>
> Create a table like:
> Create table test( col1 number, col2 number(5,2))
>
> Then see if the first column gives you back what you're seeing.  Sorry -
> not close to a computer right now
>
> Sent from my iPad
>
> On 2012-09-29, at 8:42 PM, Anssi Kääriäinen <aka...@gm...> wrote:
>
>
> On Sun, Sep 30, 2012 at 3:12 AM, Chris Gould <chr...@to...>wrote:
>
>> Arent they really both type NUMBER ?
>>
>>
> It have an (incorrect?) expectation that one column should have one result
> type in Python. While float and int are close to each other in Python, they
> do have differences, for example the '/' operator.
>
> The situation came up in trying to use outputtypefactory in Django, then
> optimizing the case where the type of the result is guessed, see
> https://github.com/shaib/django/blob/d10eaf28c864816e9bb8b0d1467e90b79291792a/django/db/backends/oracle/base.py#L772- the problem there is that half of the numbers are guessed as Decimal,
> half as int. This isn't a nice situation, the APIs for Decimal and int are
> very different.
>
> I don't know Oracle too well - is the situation such that the result is
> NUMBER in Oracle, and there is no more information about the column
> available from the DB?
>
>  - Anssi
>
>
>
>>
>> On Sunday, September 30, 2012, Anssi Kääriäinen wrote:
>>
>>> It seems it is possible to have more than one type returned for a single
>>> column. Observe this test case:
>>>
>>> import cx_Oracle
>>> print cx_Oracle.version
>>> connection = cx_Oracle.connect('user/
>>> passwd@' + cx_Oracle.makedsn('localhost', 1521, 'xe'))
>>> cur = connection.cursor()
>>> cur.execute("select case when dbms_random.random > 0.5 then 0.1 else 0
>>> end from testtable")
>>> vals = []
>>> vals.extend(row[0] for row in cur.fetchall())
>>> print set([type(v) for v in vals])
>>>
>>> The output is:
>>> 5.1.2
>>> set([<type 'float'>, <type 'int'>])
>>>
>>> To me this seems surprising - shouldn't a column have the same type
>>> across all rows in a single resultset?
>>>
>>>  - Anssi
>>>
>>
>>
>> --
>> Sent from Gmail Mobile
>>
>>
>> ------------------------------------------------------------------------------
>> Everyone hates slow websites. So do we.
>> Make your web apps faster with AppDynamics
>> Download AppDynamics Lite for free today:
>> http://ad.doubleclick.net/clk;258768047;13503038;j?
>> http://info.appdynamics.com/FreeJavaPerformanceDownload.html
>> _______________________________________________
>> cx-oracle-users mailing list
>> cx-...@li...
>> https://lists.sourceforge.net/lists/listinfo/cx-oracle-users
>>
>>
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://ad.doubleclick.net/clk;258768047;13503038;j?
> http://info.appdynamics.com/FreeJavaPerformanceDownload.html
>
> _______________________________________________
> cx-oracle-users mailing list
> cx-...@li...
> https://lists.sourceforge.net/lists/listinfo/cx-oracle-users
>
>
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://ad.doubleclick.net/clk;258768047;13503038;j?
> http://info.appdynamics.com/FreeJavaPerformanceDownload.html
> _______________________________________________
> cx-oracle-users mailing list
> cx-...@li...
> https://lists.sourceforge.net/lists/listinfo/cx-oracle-users
>
>