PHP implementation of coherent operation, chain operation Instance _php instance

The consistent operation in PHP looks really cool, and very convenient to read the code, of course, must be used in OOP, in the process of the program, there is no need to use this method. There is a useful _call to implement this method, and I write the following example, not with the _call, we can expand it.

The following is written in the SQL statement combination class, mainly used for learning, if there are students want to use, please further refine.

 * * * SQL statement combination instance class, originating article Web development notes
 * Learning, non-professional
 * * *
/class sql{
	private $sql =array ("from" => "",
			" where "=>" ",
			" "Order" => ""
			, "Limit" => "");
 
	The public function from ($tableName) {
		$this->sql[' from ']= ' from '. $tableName;
		return $this;
	}
 
	The public function where ($_where= ' 1=1 ') {
		$this->sql["where"]= "where". $_where;
		return $this;
	}
 
	Public Function order ($_order= ' ID DESC ') {
		$this->sql["order"]= "ORDER by". $_order;
		return $this;
	}
 
	Public function limit ($_limit= ') {
		$this->sql["Limit"]= "Limit 0,". $_limit;
		return $this;
	}
	Public Function Select ($_select= ' * ') {return
		' select '. $_select. " ". (Implode ("", $this->sql));
	}
 
$sql =new SQL ();
 
echo $sql->from ("TestTable")->where ("Id=1")->order ("id DESC")->limit ()->select ();
Output SELECT * from TestTable WHERE id=1 the ORDER by ID DESC LIMIT 0,10