diff --git a/cli/database-upgrade.php b/cli/database-upgrade.php
index 186eb5c..a3651db 100755
--- a/cli/database-upgrade.php
+++ b/cli/database-upgrade.php
@@ -1,141 +1,138 @@
 #!/usr/bin/php
 <?php
 # Lavazza Sport Management System by ER Informatica
 # Copyright (C) 2020 Valerio Bozzolan
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 /**
  * This is the script to upgrade the database
  *
  * It will execute the available database patches until the database
  * is to its latest version.
  *
  * To be honest, it also create the database schema if missing.
  */
 
 require __DIR__ . '/../load.php';
 
 echo <<<EOF
  _________________________________________
 / Welcome in the database upgrade script! \
 \ Good luck!                              /
  -----------------------------------------
    \        \
     \        \
      \       _\^
       \    _- oo\
            \---- \______
                  \       )\
                 ||-----||  \
                 ||     ||
 
 EOF;
 
 // path to the documentation directory
 $documentation_path = ABSPATH . '/documentation/database';
 
 // directory to the database patches
 $patch_directory = "$documentation_path/patches";
 
 // execute a random query just to check if we have a database connection
 query( 'SELECT 1' );
 
-// get the database prefix
-$database_prefix = DB::instance()->getPrefix();
-
 // try to check if the database exists
 $database_exists = true;
 try {
 	( new UserAPI() )
 		->limit( 1 )
 		->queryRow();
 
 } catch( Exception $e ) {
 	$database_exists = false;
 }
 
 if( !$database_exists ) {
 	// database schema installation
 	echo "important tables are missing! assuming no database.\n";
 	echo "importing the schema for the first time\n";
 	execute_queries_from_file( "$documentation_path/schema.sql" );
 
 	// if we have not imported any database version, just set the latest one
 	$version_exists = get_option( 'database_version', 0 );
 	if( !$version_exists ) {
 		set_option( 'database_version', DATABASE_VERSION );
 	}
 }
 
 // get the current database version
 $current_database_version = get_option( 'database_version', 1 );
 
 // notify about the current status
 printf( "current database version: %d\n", $current_database_version );
 printf( "last database version:    %d\n", DATABASE_VERSION          );
 
 // update to next database versions once at time
 while( $current_database_version < DATABASE_VERSION ) {
 
 	$current_database_version++;
 
 	$patch_name = sprintf(
 		'patch-%04d.sql',
 		$current_database_version
 	);
 
 	// path to the expected patch
 	$patch_path = "$patch_directory/$patch_name";
 
 	echo "looking for patch $patch_path\n";
 
 	// check if there is a database patch to be applied
 	if( file_exists( $patch_path ) ) {
 		execute_queries_from_file( $patch_path );
 	} else {
 		echo "\t skipped unexisting patch\n";
 	}
 
 	echo "\t increment database version to $current_database_version\n";
 
 	// update the database version
 	set_option( 'database_version', $current_database_version );
 }
 
 echo "database upgrade end. good for you!\n";
 
 
 
 
 
 
 /**
  * Execute some queries from a file
  *
  * @param string $file
  */
 function execute_queries_from_file( $file ) {
 	echo "\t executing queries from $file\n";
 
 	// get the patch content
 	$queries = file_get_contents( $file );
 
 	// replace the database prefix with the current one
 	$database_prefix = DB::instance()->getPrefix();
 	$queries = str_replace( '{$prefix}', $database_prefix,  $queries );
 
 	// execute the patch queries (it will die in case of error)
 	multiquery( $queries );
 }