Обсуждение: Getting number of tuples affected
I was looking for a function to return the number of tuples an update returned, but couldn't find anything for libpq++. Any ideas? I also noticed a bug in the docs worth mentioning... http://postgresql.nextpath.com/doxlist.html PgDatabase data; data.exec("create table foo (a int4, b char16, d float8)"); data.exec("copy foo fromstdin"); data.putline("3\etHello World\et4.5\en"); data.putline("4\etGoodbye World\et7.11\en"); &... data.putline(".\en"); data.endcopy(); There is no PgDatabase::exec thanks -Michael
On Wed, 30 Jun 1999, Michael Richards wrote: > I was looking for a function to return the number of tuples an update > returned, but couldn't find anything for libpq++. Any ideas? Added to my list of stuff to do. As to what else you can do, submit patches? :) > I also noticed a bug in the docs worth mentioning... > http://postgresql.nextpath.com/doxlist.html > > PgDatabase data; > data.exec("create table foo (a int4, b char16, d float8)"); > data.exec("copy foo from stdin"); > data.putline("3\etHello World\et4.5\en"); > data.putline("4\etGoodbye World\et7.11\en"); > &... > data.putline(".\en"); > data.endcopy(); > > There is no PgDatabase::exec Yep. Guess that should be data.Exec(... Thanks! Vince. -- ========================================================================== Vince Vielhaber -- KA8CSH email: vev@michvhf.com flame-mail: /dev/null # include <std/disclaimers.h> TEAM-OS2 Online Campground Directory http://www.camping-usa.com Online Giftshop Superstore http://www.cloudninegifts.com ==========================================================================
On Wed, 30 Jun 1999, Vince Vielhaber wrote:
> > I was looking for a function to return the number of tuples an update
> > returned, but couldn't find anything for libpq++. Any ideas?
>
> Added to my list of stuff to do. As to what else you can do, submit
> patches? :)
> > There is no PgDatabase::exec
> Yep. Guess that should be data.Exec(...
Not sure there is an Exec either :)
I've been making a pile of changes to the PgDatabase class. (Actually I
derived it). One such change is a function to quote a string you're going
to use in SQL. I'm not sure if this belongs in the PgDatabase class, but
if you think so, I'll add it before I submit the tuple count patches.
This allows me to do something like:
String updatesql(form("UPDATE users SET lastrequest='now' WHERE
loginid=%s",dbh->quote(_username).chars()));
cout << dbh->ExecTuplesOk(updatesql);
That is actually the call I needed the update count to ensure it worked...
Here is the routine:
// routine to quote any \ or ' chars in the passed string
// this isn't too efficient, but how much data are we really quoting?
String TDatabase::quote(const char *dirty) { // start with a single quote String clean("'");
const char *strptr=dirty; // escape the string if it contains any ' or \ chars while (*strptr) { if ((*strptr=='\'')
||(*strptr=='\\')) clean+='\\'; clean+=*(strptr++); } // end with a quote clean+="'";
return clean;
}
-Michael
On Wed, 30 Jun 1999, Michael Richards wrote:
> On Wed, 30 Jun 1999, Vince Vielhaber wrote:
>
> > > I was looking for a function to return the number of tuples an update
> > > returned, but couldn't find anything for libpq++. Any ideas?
> >
> > Added to my list of stuff to do. As to what else you can do, submit
> > patches? :)
>
> > > There is no PgDatabase::exec
> > Yep. Guess that should be data.Exec(...
> Not sure there is an Exec either :)
It's inherited.
>
> I've been making a pile of changes to the PgDatabase class. (Actually I
> derived it). One such change is a function to quote a string you're going
> to use in SQL. I'm not sure if this belongs in the PgDatabase class, but
> if you think so, I'll add it before I submit the tuple count patches.
I don't think it belongs in PgDatabase. I'm not even sure it belongs in
libpq++, although I can see its usefulness.
Vince.
--
==========================================================================
Vince Vielhaber -- KA8CSH email: vev@michvhf.com flame-mail: /dev/null # include <std/disclaimers.h>
TEAM-OS2 Online Campground Directory http://www.camping-usa.com Online Giftshop Superstore
http://www.cloudninegifts.com
==========================================================================
Hi. Here are some diffs that implement a function called TuplesAffected. It returns the number of tuples the last command affected, or 0 if the last command was a SELECT. I added it to the PgConnection because it contains the Exec method as well as the PQresult structure. Maybe farther down in the inheritance there should be a function that executes a query and returns the number of tuples affected or returned (according to whether it was a select or not) or a -1 on error. Patches are attached... -Michael
Thus spake Michael Richards
> Here are some diffs that implement a function called TuplesAffected. It
> returns the number of tuples the last command affected, or 0 if the last
> command was a SELECT. I added it to the PgConnection because it contains
Why not overload PGTuples() instead (assuming it doesn't already do this)?
--
D'Arcy J.M. Cain <darcy@{druid|vex}.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 424 2871 (DoD#0082) (eNTP) | what's for dinner.
On Wed, 30 Jun 1999, D'Arcy J.M. Cain wrote: > Thus spake Michael Richards > > Here are some diffs that implement a function called TuplesAffected. It > > returns the number of tuples the last command affected, or 0 if the last > > command was a SELECT. I added it to the PgConnection because it contains > > Why not overload PGTuples() instead (assuming it doesn't already do this)? Tuples returned tells you how many you can get using the getvalue series. If you tried that with an update, it core dumps. I think the two are really related, but fundamentally different. -Michael
Thus spake Michael Richards
> > Why not overload PGTuples() instead (assuming it doesn't already do this)?
As mentioned in another posting, I meant PQntuples().
> Tuples returned tells you how many you can get using the getvalue series.
> If you tried that with an update, it core dumps. I think the two are
> really related, but fundamentally different.
I'm just thinking that it's easy for PQntuples() to tell what it has
to return and branch accordingly. It just makes it easier to remember
the function. No asking which get tuple count function works for update
and which for select.
--
D'Arcy J.M. Cain <darcy@{druid|vex}.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 424 2871 (DoD#0082) (eNTP) | what's for dinner.