On 03/23/2014 08:19 AM, jared wrote:
My full function works fine as a standalone python script, but I was
having trouble getting it to work in Posgres.
Outside of Postgres it worked fine (because I was feeding in lists of
dates to test on).
The I did the script with psycopg2 calling in the below table and it
worked fine. (in the docs for psycopg2 it says it converts the
timestamps into python dates, this would explain why it is working in
this scenario)
I finally figured out what the issue is, when using plpython and pulling
a date out of Postgres, it is treating it as text - is that intended or
am I doing something wrong?
Intended:
http://www.postgresql.org/docs/9.3/interactive/plpython-data.html
FYI, it would be a good idea to include the Postgres version. plpython
has been undergoing a lot of changes recently, so it would help to peg
where you are at in that sequence.
So the question is - why is plpython returning subject_a[0] as text
rather than an actual date that python can operate on?, is that
intended? (trying to learn how to think about this is a Postgres way)
See above.
Granted,
There is a workaround, I can just change my function to read:
return datetime.strptime(subject_a[0], '%Y-%m-%d %H:%M:%S') + defined_period
instead of:
return subject_a[0] + defined_period
However,
I am just trying to figure out why if postgres knows it is a day, it is
not telling python that in the function - like it would when I use psycopg2?
Because psycopg2 has an additional typecasting/adaptation code:
http://initd.org/psycopg/docs/usage.html#adaptation-of-python-values-to-sql-types
I find dateutil(https://labix.org/python-dateutil) a handy package to
have in this situation. Use parse() from the parser module to do the
heavy lifting of converting from a string into a date/datetime object.
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
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