PHP implements the chain operation principle, and php implements the chain operation

PHP implements the chain operation principle, and php implements the chain operation

There are multiple methods in a class. When you instantiate this class and call methods, you can only call them one by one. For example:

Db. php

<?php

class db
{
    public function where()
    {
        //code here
    }
    public function order()
    {
        //code here
    }
    public function limit()
    {
        //code here
    }
}

Index. php

<?php

$db = new db();

$db->where();
$db->order();
$db->limit();

To implement a chained call, add return $ this at the end of the method.

Db. php

<?php

class db
{
    public function where()
    {
        //code here
        return $this;
    }
    public function order()
    {
        //code here
        return $this;
    }
    public function limit()
    {
        //code here
        return $this;
    }
}

Index. php

<?php

$db = new db();

$db->where()->order()->limit();