Dear Monks,

Thank you for your time and effort reading and relpying to my question.

I am sure that this question it is not a challenge for most of you but it seems that I can not find an answer to such a simple question.

I want to create a Database, table, and insert some data on MySQL database. The problem comes that I also want to check if all of these elements exist before I send the request to create them.

The only solution that I have found so far is to connect and disconnect from the DB after the completion of one process. This not only makes my code slower but also I am sending multiple request.

I am sure that it can be done with one request from beginning. I tried to find a command to use such as use "db" same as MySQL syntax, but so far not successfully.

The reason that I am connecting and disconnecting is that the script will complain that it "can not find the database" alternatively.

Sample of my code is provided under:

#!/usr/bin/perl

use strict;
use warnings;
use DBD::mysql;

$|=1; #flush every time the program

my $db = 'xxxx';
my $port = '3306'; # default
my $host = 'localhost'; # or external
my $pass = 'xxxx';
my $user = 'xxxx';
my $table = 'xxxx';
my $checkExist;

sub mysql {

    my $dbh = DBI->connect("dbi:mysql::".$host.":".$port."", 
               "".$user."",
               "".$pass."", 
               { 'PrintError' => 1, 'RaiseError' => 1 } 
    ) or die "Could not connect to ".$host.": ". $DBI::errstr ."\n";

    my $databases = $dbh->do("SHOW DATABASES LIKE '".$db."'") or die "
+Error: " .dbh->errstr. "\n";

    if ($databases eq 1) {
    printf "Database: ".$db." exists not creating: ".$db."\n";
    }
    else {
    printf "Database: ".$db." does not exist creating: ".$db."\n";

    $checkExist = $dbh->prepare("CREATE DATABASE IF NOT EXISTS `".$db.
+"`") or die "Could not create the: ".$db." error: ". $dbh->errstr ."\
+n";

    if (!$checkExist->execute()) {
        die "Error: ". $checkExist->errstr ."\n";
    }

    $checkExist->finish();

    $dbh->disconnect();

    } # End of else

    $dbh = DBI->connect("dbi:mysql:".$db.":".$host.":".$port."", 
            "".$user."",
            "".$pass."", 
            { 'PrintError' => 1, 'RaiseError' => 1 } 
    ) or die "Could not connect to ".$host.": ". $DBI::errstr ."\n";

    my $tables = $dbh->do("SHOW TABLES FROM `".$db."` WHERE Tables_in_
+".$db." LIKE '".$table."'") or die "Error: " .dbh->errstr. "\n";

    if ($tables eq 1) {
    printf "Table: ".$table." exists not creating: ".$table."\n";
    }

    else {
    printf "Table: ".$table." does not exist creating: ".$table."\n";

    $checkExist = $dbh->prepare("CREATE TABLE IF NOT EXISTS `".$table.
+"` (
                    `id` int(11) NOT NULL AUTO_INCREMENT,
                    `UnixTime` int(11) NOT NULL,
                    `losses` int(11) NOT NULL,
                    PRIMARY KEY (`id`)
                    ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREM
+ENT=1 ;");

    if (!$checkExist->execute()) {
        die "Error: ". $checkExist->errstr ."\n";
    }

    $checkExist->finish();

    $dbh->disconnect();

    } # End of else

    my $range = 50;
    my $minimum = 100;

    my $random_number = int(rand($range)) + $minimum;
    my $time = time();

    my $losses = $time . ' ' . $random_number;

    $dbh = DBI->connect("dbi:mysql:".$db.":".$host.":".$port."", 
            "".$user."",
            "".$pass."", 
            { 'PrintError' => 1, 'RaiseError' => 1 } 
    ) or die "Could not connect to ".$host.": ". $DBI::errstr ."\n";

    $checkExist = $dbh->prepare("INSERT IGNORE INTO `".$table."` (`Uni
+xTime`, `losses`) VALUES ('".$time."','".$random_number."') ");

    if (!$checkExist->execute()) {
    die "Error: ". $checkExist->errstr ."\n";
    }

    $checkExist->finish();

    $dbh->disconnect();

    return $losses;

} # End of mysql sub

my $output = &mysql();

print "Added:" .$output. "\n";

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In reply to MySQL avoid multiple connect request by thanos1983

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