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Re: Perl DBI connect cached still active

by tybalt89 (Prior)
on Oct 29, 2020 at 01:53 UTC ( #11123286=note: print w/replies, xml ) Need Help??


in reply to Perl DBI connect cached still active

See $if_active in perldoc DBI

check line marked HERE in this sample of code ( since you didn't provide a Short, Self-Contained, Correct Example )

#!/usr/bin/perl use strict; # https://perlmonks.org/?node_id=11123285 use warnings; use DBI; my $dbfile = 'db.11123285'; unlink $dbfile; my $db = DBI->connect_cached( "DBI:SQLite(RaiseError=>1,PrintError=>0):$dbfile"); eval { $db->do('create table note (id integer primary key, ts int, mess tex +t)'); $db->do('insert into note (ts, mess) values (?, ?)', {}, 1, 'one'); $db->do('insert into note (ts, mess) values (?, ?)', {}, 2, 'two'); }; #system "sqlite3 $dbfile .dump"; my $sth = $db->prepare_cached('select * from note where id = ?'); $sth->bind_param(1, 2); $sth->execute; my @data = $sth->fetchrow_array; use Data::Dump 'dd'; dd \@data; $sth = $db->prepare_cached('select * from note where id = ?', {}, 1); +# HERE $sth->bind_param(1, 1); $sth->execute; @data = $sth->fetchrow_array; use Data::Dump 'dd'; dd \@data; unlink $dbfile; # cleanup

Outputs:

[2, 2, "two"] [1, 1, "one"]

Note that the "still Active" message does not prevent correct execution, so something else must be causing your lack of data.

Replies are listed 'Best First'.
Re^2: Perl DBI connect cached still active
by newperldeveloper (Sexton) on Oct 29, 2020 at 11:03 UTC
    When I send in the same parameter to the second query I am getting 0 rows. Which is impossible because the first returns data. I did get the message statement handle DBI::st=HASH(0x20e3278) still Active, that is the reason I used $parent_sth->finish() thinking that would clear anything up. It gets rid of the message but the second query does not execute.

      Maybe the (Sybase) database driver doesn't like only half-fetching the resultset? Have you tried fetching the complete resultset and then issuing your second query? Something like:

      my $prod_dbh = DBI->connect_cached('DBI:Sybase:database','web_','web') + || die "Couldn't connect to DB!\n" . DBI->errstr; my $parent_sth = $prod_dbh->prepare_cached('select * from table where +id = ?'); $parent_sth->bind_param(1,$id); $parent_sth->execute(); my $parent_data = $parent_sth->fetchall_arrayref(); ... my $child_sth = $prod_dbh->prepare_cached('select * from table2 where +id = ?'); $child_sth->bind_param(1,$parent_data[0]); $child_sth->execute(); my $child_data = $child_sth->fetchall_arrayref(); print Dumper($child_data->[0]);

      Of course, with your statement handles named $parent_data and $child_data, maybe you are trying to fetch data in a parent/child relationship where you instead could be doing an SQL JOIN between the two tables to issue only a single query?

      select parent.* , child.* from table parent join table2 child on (parent.id=child.id) where parent.id = ?

        Corion++ Sybase will fail if you finish an sth when there are unread results. You can override that by setting the syb_flush_finish attribute

        my $prod_dbh = DBI->connect_cached('DBI:Sybase:database','web_','web +' {syb_flush_finish => 1})
        but that wouldn't be my recommendation. I find most cases of extracting data are better suited by using selectall_arrayref. Sure you lose the re-usability of prepared statements (I only used those if I'm in a loop) and you may have memory issues if the data being returned is huge but I find the vast majority of my use cases are better served by the simplicity of selectall_arrayref:
        my $parent_data = $prod_dbh->selectall_arrayref('select * from table + where id = ?', {Slice => {}}, $id );
        -derby

      Maybe $parent_data[0] is not what you think it is...

      Try adding RaiseError=>1 like my example showed. Perhaps there is some other error you are not testing for.

      Also try using prepare instead of prepare_cached

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