PHP SQL

<?php

interface SomeOtherSQL{

  const HelloWorld = [
    "SELECT 'hello' as 'world';"
  ];
}

interface Example extends SomeOtherSQL{

  const EchoExample = [
    'in'=>[
      'pin'=>'VARCHAR(50)'
    ],
    "SELECT {0} as 'input';"
  ];

  const AddExample = [
    'in'=>[
      'pa'=>'VARCHAR(50)',
      'pb'=>'VARCHAR(50)'
    ],
    "SELECT {0}+{1} as 'added';"
  ];

}


class sql_base{
  static function __callStatic($command,$params){
    $marks = str_pad("",count($params)*2-1,"?,");
    $host     = static::$host;
    $username = static::$username;
    $database = static::$database;
    $port     = static::$port;
    $password = static::$password;
    $dsn      = "mysql:host=$host;port=$port;dbname=$database";
    $db = new PDO($dsn, $username, $password);
    $query = $db->prepare("SHOW PROCEDURE STATUS where `Name`=? AND `Db`='$database'");

    $query->execute(array($command));
    $procExists = $query->fetch(PDO::FETCH_ASSOC,PDO::FETCH_ORI_NEXT);
    if(!$procExists)
    {
      $class = get_called_class();
      if(defined("$class::$command")){
        $code = constant("$class::$command");
        $sql = "";
        $i=-1;
        while(isset($code[++$i])){
          $sql.=$code[$i]."\n";
        }
        $type = isset($code['type'])?$code['type']:"procedure";
        $newParams = [];
        foreach(['in','out'] as $d){
          if(isset($code[$d]))foreach($code[$d] as $p=>$n){
            $newParams[] = $type=="procedure"?"$d `$p` $n":"`$p` $n";
          }
        }
        if(isset($code['in'])){
          $paramKeys = array_keys($code['in']);
          $sql = preg_replace_callback("/\\{([0-9]+)\\}/",function($matches) use (&$paramKeys){
            return '`'.$paramKeys[$matches[1]].'`';
          },$sql);
        }
        $newParams = implode(", ",$newParams);
        $procSql = "CREATE $type $command($newParams) \n BEGIN $sql \n END";

        $query = $db->prepare($procSql);
        if(!$query)
          throw new Exception(json_encode($db->errorInfo()));
        else if(!$query->execute())
          throw new Exception(json_encode(array("errorinfo"=>$query->errorInfo(),"parameters"=>$newParams,"sqlcode"=>$code)));
      }
      else throw new Exception("Missing sql procedure '$command'");
    }

    $query = $db->prepare("CALL $command($marks)");
    if(!$query)
      throw new Exception(json_encode($db->errorInfo()));
    else{
      if(!$query->execute($params)) throw new Exception(json_encode(array($query->errorInfo(),$params)));
      else{
        $return = $query->fetchAll(PDO::FETCH_ASSOC);
        if(count($return)==0)return $db->lastInsertId();
        return $return;
      }
    }
  }
}




class sql extends sql_base implements Example{ // fill out fields
  protected static $host = "";
  protected static $username = "";
  protected static $database = "";
  protected static $port = "";
  protected static $password = "";

}

print_r(sql::HelloWorld());
echo "<br>";
print_r(sql::AddExample(3,4));
echo "<br>";
print_r(sql::EchoExample("uwotm8"));



?>