Passing Database class into constructor?

Question

What's a better practice? To pass database or open database? I'm unable to do an auto-complete (NetBeans PHP IDE) when I pass a database into the constructor.

class Item {
    private $name;
    private $database;

    public function __construct($database, $id) {
        $information = $database->fetchSingleRow($id);

        $this->database = $database;
        $this->name = $information['name'];
    }
}

Should I do this

class Item {
    private $name;
    private $database;

    public function __construct($id) {
        $this->database = new Database();
        $this->database->open();
        $this->database->select('test'); // selects test table

        $information = $this->$database->fetchSingleRow($id);
        $this->name = $information['name'];
    }

    public function __destruct() {
        unset($this->item);
        $this->database->close();
    }
}

user499054 · Accepted Answer · 2011-03-16 01:01:10Z

1

I'd personally pass it as an argument in the constructor. If you have many instances of Item, a new connection is created every time, which would strain your database.

answered Mar 16, 2011 at 1:01

user499054

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Comments

alex · Accepted Answer · 2011-03-16 01:04:47Z

1

Several things:

A DB object is usually better to get by factory/singelton/registery and not move it around. Unless you have the ability to hold thousands of open connections in one request.
if you want auto complete - put a type hint in the function declaration

public function toto(DataBaseClass $MyDB,array $params){...}

edited Mar 16, 2011 at 1:04

alex

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answered Mar 16, 2011 at 1:00

Itay Moav -Malimovka

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Comments

Mike Lewis · Accepted Answer · 2011-03-16 01:08:00Z

0

It has already been covered that creating a new instance of the database everytime you instianiate an Item will become a strain on the DB, but I would also like to point that it really wouldn't be a good design decision.

The main problem here is that you aren't following the "principle" of speration of design. If you were to have Item create a new Database object, you'd run into issues down the road of if you wanted to change ANYTHING about how the database was created/open/etc. You'd have to change everywhere in your codebase that created a new Database instance. Thus not being ready for change.

answered Mar 16, 2011 at 1:08

Mike Lewis

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