開発スタッフがアプリ関連の最新技術やニュースをご紹介します。

最初のツイートが高額で落札されたニュースでNFTという単語を見て
NFTとはいったい何なのかと興味を持ったので少し調べてみました。

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I will continue to talk about magic methods article I wrote last week. For the part 1, you can read here.

ToString

The magic __toString () method allows you to define what you would like to display when an object of the class is treated as a string. If you use echo or print on your object, and you haven’t defined the __toString () method, it will give an error.

<?php
class Student {
    private $name;
 
    public function __construct($name) 
    {
        $this->name = $name;
        $this->email = $email;
    }
 
    public function __toString()
    {
        return 'Name: '.$this->name;
    }
}
 
$student = new Student('Yuuma');
echo $student;
?>

Call

If the __get () and __set () methods are called for non-existent properties, the __call () method is called when trying to invoke inaccessible methods, the methods that have not been defined in your class.

<?php
class Student {
    public function __call($methodName, $arg) 
    {
        // $methodName = getName
        // $arg = array('1')
    }
}
 
$student = new Student();
$student->getName(1);
?>

Isset

The magic __isset () method is called when you call the isset () method on inaccessible or non-existent object properties. Let’s see how it works with an example.

<?php
class Student {
    private $data = array();
 
    public function __isset($name) 
    {
        return isset($this->data[$name]);
    }
}
 
$student = new Student();
echo isset($student->email);
?>

Invoke

The magic __invoke () method is a special method that is called when you try to call an object as if it were a function. the $student object is treated as if it were a function, and since we have defined the __invoke () method, it will be called instead of giving you an error. The main purpose of the __invoke () method is that if you want to treat your objects as callable, you can implement this method.

<?php
class Student {
    private $name;
 
    public function __construct($name) 
    {
        $this->name = $name;
    }
 
    public function __invoke()
    {
        echo 'Invoke function';
    }
}
 
$student = new Student('John');
$student();
?>

There are still some magic methods in PHP but let me stop here as I had written most used methods in article part 1 and part 2. If you are interest for more, you can check it out in PHP official documentation.

Yuuma

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Here is some tips based on my experience to speed up database queries.

Table Indexing

Indexes are important part in database. Indexes are used to quickly retrieve data without having to search every row in a database table is accessed. The users cannot see the indexes, they are just used to speed up searches/queries.

How to use? For example, you have thousands of rows of users and you want to get an email.

Select * from users where email = “me@gmail.com”

Without index, this process will be from top to bottom until it the email is found.

Using with index, in Laravel, the easy way is to create a migration file.

public function up()
{
   Schema::table(‘users’, function(Blueprint $table)
   {
     $table->index(‘email’);
   });
}

Or if you currently on fresh project just add index to column you want to

public function up()
{
    Schema::create(‘users, function(Blueprint $table) {
      …
      $table->index(‘email’);
      …
    });
}

Index is not only for single column. You can use multiple column like this  $table->index([‘email’, ‘ phone_no’]); Let’s us look at a query that could use two different indexes on the table based on the WHERE clause restrictions. Multi column indexes are called compound indexes.

Eloquent Eager Loading

At its core Eager Loading, is telling Eloquent that you want to grab a model with specific relationships that way the framework produces a more performant query to grab all the data you will need. By eager loading, you can take many queries down to just one or two. Wrong implementation cause N+1. Here is where common developer do which cause N+1.

For example:

Class Post extends Model
{
  public function author()
  {
    return $this->belongsTo(Author::class);
  }
}

Lets fetch author about 100 rows from the table and what happen

Mistake 1

$post = Post::all();
foreach($posts as $post) 
{
  $total_user = $post->author;
}

The query runs once to get all the author and for each loop it query another query for author for 100 times. 100 + 1 = N+1 problem. Imagine if you want to fetch thousand to data. If one query cost 100ms * 100 = 10,000ms it takes to complete process.

Solution

It can be solve by using with method in Eager loading. For example

$post = App\Post::with(‘author’)->get();

If you had multiple related associations, you can eager load them with an array:

$post = App\Post::with([‘author’, ‘comments’])->get();
$post =App\Post::with(‘author.profile’)->get();

With this, instead of hitting database N+1, with will single query by joining those table and transform it into collection. So you can freely access the collection object without hitting the database.

By Ami

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今回はUnityのUI Canvasの中から代表的なもの「InputField」「Button」「Text」の使用方法をシェアしたいと思います。

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TP-Linkから全ポート10GBASE-T対応のアンマネージドL2スイッチが
リリースされていました。

家庭用10ギガLAN環境が手軽に構築できます。

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