Using query parameters subtitution outside of execute()
Daniele Forghieri
guru at digitalfantasy.it
Fri Mar 28 07:54:11 EDT 2014
Il 28/03/2014 10:16, Peter Otten ha scritto:
> Daniele Forghieri wrote:
>
>> Hi to all. I'm using sqlite3 with python 2.7 on windows.
>>
>> I use the query substitution parameters in my query but I need to pass
>> part of the query to a function, something like (it's not the real
>> examples, just to clarify the question):
>>
>> def loadAll(cursor, id, queryAdd = None):
>> if queryAdd is None:
>> qry = 'select * from files where catalog = ?'
>> else:
>> qry = 'select * from files where catalog = ? and %s' %
>> (queryAdd))
>>
>> cursor.execute(qry, (id, ))
>> ...
>>
>> I would like to use the query substitution even when I create, in
>> another piece of code, the queryAdd part, something like:
>>
>> queryAdd = cursor.querySubst('enabled = ? and hide = ? and data > ?',
>> (enabled, hidden, min_date, ))
>>
>> when the function take care of the date format, quoting the parameter
>> and so on
>>
>> It's possible or not ?
> You can use named parameters
>
> http://docs.python.org/dev/library/sqlite3.html#cursor-objects
>
> Your function might become (untested)
>
> def load_all(cursor, parameters, condition="catalog = :id"):
> query = 'select * from files where ' + condition
> cursor.execute(query, parameters)
> ...
>
> load_all(
> cursor, dict(id=42, fromdate=datetime.date.today()),
> condition="catalog = :id and date >= :fromdate")
>
Thank. With this I can solve the problem but I have to specify the
query twice and if I have to change something I need to made it
everywhere I use the function and is something I would like to avoid.
I also don't like very mush to pass or create a dict for a function
call but that's probably me coming from old plain C ;)
Daniele Forghieri
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