[Pytables-users] dates and space

[Oleksandr H. <guz...@gm...>]

Hi Pytables users and developers:

I have a few questions to which I could not find the answer in the
documentation. Thank you in advance for any help.

1. If I store dates in Pytables, does it mean I could write queries like
table.where('date.month == 5')? Is there a common way to pass from python's
datetime to pytable's datetime and inversely?

2. I have several variables stored in the same file in a separate table for
each variable. And I use separate columns year, month, day, hour, minute,
second  - to mark the time for a record (the records are not necessarily
ordered in time) and this is for each variable. I was thinking to put all
the variables in the same table and put missing values for the variables
which do not have outputs for a given time step. Is it possible to put None
as a default value into a table (so I could easily filter dummy rows).
But then again the data comes in chunks, does this mean I would have to
check if a row with the same date already exist for a different variable?


I don't really like the ideas in 2, which are intended to save space, but
maybe all I need is a good compression level? Can somebody advise me on
this?



Cheers
--
Oleksandr (Sasha) Huziy