Re: Getting the time during a transaction

Hi Gerhard. Ah well, that completely explains this. Many thanks, it did 
not assume an issue with rowcount so used it as I had previously. On 
another note, do you have any favorite way of faking a sequence in 
SQLite. I am using sequence in postgres to keep track of the 
commit_order of transactions.

ie create sequence commit_seq;

I am already autoincrementing my transaction id in SQLite by doing

create table ztransaction (
tid integer primary key,
packed boolean not null default false,
commit_order integer not null unique,
..more fields
);

My commit_seq in postgres is used to give me the next value for my 
commit_order field for my table. So I'd normally be doing this:

insert into ztransaction (tid, commit_order, username, description, 
extension) values (%s, (select nextval('commit_seq')), %s, %s, %s)

My thought is to use something like single field table and alter the 
value of it. I guess I could also make a pysqlite function that would 
just return the next value of the current value. I may just have to be 
explicit about putting it in begin and end to do both statements in a 
single transaction to be sure the value doesn't change perhaps. In any 
case, any ideas here would also be a help.

Regards,
David






Regards,
David

Gerhard Häring wrote:
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 > David Pratt wrote:
 >> Hi Tim. It was a surprise to me as well! The thing that screwed me up
 >> was assert cursor.rowcount. Hmm, it should be 1 since I am getting a
 >> result from .fetchone but is reporting -1. I incorrectly assumed I was
 >> getting nothing from my select statement. Any idea about this? Why 
is it
 >> not giving me a rowcount of 1 so my assertion is correct? [...]
 >
 > The pysqlite docs say why:
 > http://initd.org/pub/software/pysqlite/doc/usage-guide.html
 >
 > """
 > rowcount attribute
 >
 > Although pysqlite's Cursors implement this attribute, the database 
engine's
 > own support for the determination of "rows affected"/"rows selected" 
is quirky.
 >
 > For SELECT statements, rowcount is always -1 because pysqlite cannot
 > determine the number of rows a query produced until all rows were 
fetched.
 >
 > For DELETE statements, SQLite reports rowcount as 0 if you make a DELETE
 > FROM table without any condition.
 >
 > For executemany statements, pysqlite sums up the number of modifications
 > into rowcount.
 >
 > As required by the Python DB API Spec, the rowcount attribute "is -1 in
 > case no executeXX() has been performed on the cursor or the rowcount 
of the
 > last operation is not determinable by the interface".
 > """
 >
 > - -- Gerhard
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