On Saturday, November 1, 2014 12:31:38 PM UTC-7, Luis Ramos wrote:
>
> Anthony, thanks for your response, the only inconvenience that I see is
> that the 'update_date' Field will be updated if there's a change in the
> whole Row, instead of a particular Cell. How can we specify to update if a
> particular Cell changed?
>
>
What do you mean by "a particular Cell"? For a relational DB, my
understanding is that a *row* is one entry, and that values of a particular
column in that row don't have any independent existence. You can't change
1 column without changing the whole row, even though the values in other
columns of that row may not change.
Am I misunderstanding RDBs, or misunderstanding your question?
/dps
> On Friday, October 31, 2014 10:24:15 PM UTC-4, Anthony wrote:
>>
>> Does this work:
>>
>> db.define_table('dogs', ...,
>> Field('creation_date', 'datetime', default=now),
>> Field('update_date', 'datetime', default=None, update=now
>> ))
>>
>> Then in your update_or_insert, don't explicitly specify either of those
>> fields and let the default/update attributes handle it.
>>
>> Anthony
>>
>> On Friday, October 31, 2014 5:47:41 PM UTC-4, Luis Ramos wrote:
>>>
>>> I'm currently using this method to insert new elements. How can I update
>>> the 'update_date' field only if there's an update and only insert the
>>> 'creation_date' one time?
>>>
>>> import datetime
>>>
>>> now = datetime.datetime.now()
>>>
>>> db.define_table('dogs', Field('name'),
>>> Field('owner'),
>>> Field('address'),
>>> Field('creation_date', 'datetime'),
>>> Field('update_date', 'datetime'))
>>>
>>>
>>> q1 = db.dogs.name == 'Paco'
>>> q2 = db.dogs.owner == 'Rob'
>>>
>>> db.dogs.update_or_insert((q1) & (q2), name='Paco', owner='Rob',
>>> creation_date=now)
>>>
>>
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