On 25/03/12 17:14, Bill House wrote:
[snip]
> Sometimes it is helpful to know how many records one is working with.
>
> From my reading in the psycopg2 documentation (2.4.4) and
> experimentation, I think that this information is only available if one
> uses an unnamed cursor (in which case all the data will have been
> fetched to the client) or with an named cursor (but only after all the
> data has been fetched).
>
> If there is a large amount of data, this may be problematic.
Not at all. You just need to MOVE to the end of the result set and count
how many rows you skipped. At the moment psycopg doesn't use MOVE return
value (that tells you what you want to know) but can just .execute() the
MOVE and access the result on the cursor. Also, we could probably extend
scroll() to return the number of scrolled rows in the future.
> In particular, I am interested in:
> 1) the python string substitution technique I used
Use bound parameters:
http://packages.python.org/psycopg2/usage.html#query-parameters
federico