#!/usr/bin/perl -w
use DBI;
my $dbh = connectpgdb('****','****','****','Pg','localhost');
my $n = getsqlvalue($dbh,"select count(*) from blog");
print $n;

sub connectpgdb { # this is used to connect with DBD::Pg
    my ($database,$user,$password,$driver,$server) = @_;
    my $url;
    unless ($driver) {
        $driver   = "Pg";
    }
    unless ($server) {
        $url      = "DBI:$driver:dbname=$database;host=localhost";
    }
    else {
        $url      = "DBI:$driver:dbname=$database;host=$server;port=5432";
    }
    unless ($user) {
        $user     = "****";
        $password = "****";
    }
    my $dbh = DBI->connect( $url, $user, $password,{AutoCommit=>1,RaiseError=>1,PrintError=>1}) or die "connectdb can't connect to psql: $!\n";
    return $dbh;
}
sub getsqlvalue {
    my @results = ();
    my ($dbh,$sqlstatement)= @_;
    my $sth = $dbh->prepare($sqlstatement);
    my @row;
    $sth->execute || die "Could not execute MySQL statement: $sqlstatement";
    while (@row=$sth->fetchrow_array) { push(@results, [ @row ]); }
    $sth->finish();
    return $results[0][0];
}