Dump prepared sql query from DBI statement in PERL

Question

im using DBI in Perl to connect to my PostgreSQL Database. Everything is working fine but in my debugging (printing results etc.) iam not able to see if the query prepared b

Answer 1

Use the DBI tracing facility. It works like this:

use strict;
use warnings;
use DBI;
my %opt = ( RaiseError => 1 );
my $dbh = DBI->connect( 'dbi:mysql:test', 'fred', 'secret', \%opt );
$dbh->trace(2); # level 2 shows statement with inserted parameters
my $sql_i = 'insert into t1 (a, b) values ( ?, ? )';
my $sth_i = $dbh->prepare( $sql_i );
for ( qw/ eins zwei drei / ) {
    $sth_i->execute( $_, $_ );
}
$dbh->disconnect;

Answer 2

DBI supports the following: There is the DBI->trace($tracefile_handle) method (traces all DBI interactions), or $dbh->trace($tracefile_handle) which would trace just the interactions on a specific handle. Output defaults to STDERR, but by supplying $tracefile_handle, you can explicitly send output to a different file (or just use shell redirection).

DBD::pg also supports $h->trace('SQL'); This must be supported by your DBD driver to work, but fortunately DBD::Pg does support the feature.

The documentation for DBI, at CPAN - DBI, and for DBD::Pg at CPAN - DBD::Pg really gives you all you need to know on tracing.

Answer 3

Beyond the tracing others have mentioned you should look at https://metacpan.org/pod/DBI#Statement which gives you the SQL last executed and https://metacpan.org/pod/DBI#ParamValues and https://metacpan.org/pod/DBI#ParamTypes which tell you about your parameters.

There is also DBIx::Log4perl which can log what you want without all the DBI tracing.