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| Author |
Query returns -1 if row present (DBI, SQL Server 2000)
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| int eighty 2007-10-29, 7:06 pm |
| Hello,
I am using the DBI module to interface with a SQL Server 2000 database
-- connection, INSERT, UPDATE, and SELECT (when 0 rows exist in
resultset) are fine. However, if the resultset contains a row, a
value of -1 is returned. The query is very simple:
my $sth = $dbh->prepare(q{SELECT TOP 1 id FROM host WHERE ip = ?});
$sth->execute($ip);
print "Looked up $ip: " . $sth->rows . " ($DBI::errstr)\n";
if ($sth->rows == 0) {
# do something
}
elsif ($sth->rows > 0) {
# do something else
}
else {
# error
}
I do not believe this to is a permission problem with SQL Server as
the initial SELECT runs and jumps properly when $sth->rows is 0.
However the code always ends up in the else block if a row is returned
from the initial SELECT. The SELECT query also runs fine in Query
Analyzer when entered manually. Oh, it may also be worth mentioning
that $DBI::errstr is empty after the execute call for the initial
SELECT query.
TIA.
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| J. Gleixner 2007-10-29, 7:06 pm |
| int eighty wrote:
> Hello,
>
> I am using the DBI module to interface with a SQL Server 2000 database
> -- connection, INSERT, UPDATE, and SELECT (when 0 rows exist in
> resultset) are fine. However, if the resultset contains a row, a
> value of -1 is returned. The query is very simple:
>
> my $sth = $dbh->prepare(q{SELECT TOP 1 id FROM host WHERE ip = ?});
> $sth->execute($ip);
> print "Looked up $ip: " . $sth->rows . " ($DBI::errstr)\n";
>
> if ($sth->rows == 0) {
> # do something
> }
>
> elsif ($sth->rows > 0) {
> # do something else
> }
>
> else {
> # error
> }
>
> I do not believe this to is a permission problem with SQL Server as
> the initial SELECT runs and jumps properly when $sth->rows is 0.
> However the code always ends up in the else block if a row is returned
> from the initial SELECT. The SELECT query also runs fine in Query
> Analyzer when entered manually. Oh, it may also be worth mentioning
> that $DBI::errstr is empty after the execute call for the initial
> SELECT query.
Possibly, reading the documentation will help.
"Returns the number of rows affected by the last row affecting command,
or -1 if the number of rows is not known or not available. "
[ continue reading docs for more information.]
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| int eighty 2007-10-29, 7:06 pm |
| On Oct 29, 2:35 pm, "J. Gleixner" <glex_no-s...@qwest-spam-no.invalid>
wrote:
> int eighty wrote:
>
>
>
>
>
>
>
> Possibly, reading the documentation will help.
>
> "Returns the number of rows affected by the last row affecting command,
> or -1 if the number of rows is not known or not available. "
>
> [ continue reading docs for more information.]
What a surprise that something I often advocate actually works. That
is an unexpected aspect of the rows method, as I anticipated the
functionality would be similar to http://us.php.net/manual/en/functio...li-num-rows.php
The documentation doesn't lie, though. Many thanks.
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