Use PHP script to assist MySQL database management 3-delete duplicate table index

<?php
$dbi = new DbMysql;
$dbi->dbh = 'mysql://root:[email protected]/coffeetest';

$map = array();
$dbi->fetchMap("SHOW TABLES", $map);
$tables = array_keys($map);
for($i=0; $i<count($tables); $i++){
    echo($tables[$i]."\n");
    $sql = "SHOW INDEX FROM ".$tables[$i];
    $list = $dbi->fetchAll($sql);
    $indexs = array();
    foreach($list as $item){
        $indexs[$item['Key_name']][] = $item['Column_name'];
    }
    $j = 0;
    $list = array();
    foreach($indexs as $key=>$val){
        $list[] = array('j'=>$j, 'key'=>$key, 'val'=>implode(",",$val));
        $j++;
    }
    $count = count($list) - 1;
    for($j=$count; $j>=0; $j=$j-1){
        $me = $list[$j];
        foreach($list as $item){
            if($item['j']<$me['j'] && $item['val']==$me['val']){
                echo("\t".$j."\t".$me['key']."\t".$me['val']."\n");
                $sql = "ALTER TABLE ".$tables[$i]." DROP INDEX `".$me['key']."`";
                $dbi->execute($sql);
            }
        }
    }
}
?>