Re: [Pypgsql-users] executemany question

[<gh...@gh...>]

Steve Waterbury wrote:
> I may be misunderstanding the purpose of
> cursor.executemany(query, sequence_of_params) ...
> 
> The doc says "Execute a query many times, once
> for each params in the sequence."  I had hoped
> the results would accumulate in the cursor, but
> it doesn't appear to (perhaps I'm doing something
> wrong!).  Here's what I'm doing:
> 
> curs.executemany('select * from docs where doc_number = %s', docnums)

executemany is not supposed to be used with SELECTs. Use it for INSERT 
or UPDATE only.

> in which docnums is a list of strings, which are
> values of doc_number.  (I've verified that they are
> valid.)  Then when I then do
> 
> curs.fetchall()
> 
> ... I get only the result of the execution of the query
> using the last item in the list (which is certainly what
> you get by doing several "execute(query, parms)"
> in succession).
> 
> Is this the way it's supposed to work?
> 
> And if so, what would be a good way of doing what I want to
> do (i.e., feed in a sequence of parameters and get
> back a cumulative result of executing the same
> query with each one)? [...]

In your particular example:

docnums = [3,4,5,6]
curs.execute("select * from docs where doc_number in %s", (docnums,))

Other problems will require other solutions.

-- Gerhard