CODEWITHSUNDEEP
phpoopclass
user1246035
user1246035

Reputation: 81

php creating a class variable

Hello i'm using php and i'm trying to make a database class where the constructor will connect the class to the database and assign the pointer to a class variable. The problem that I have is that every time a new instance of the class is created, the constructor gets called and the code connects to the database. I don't see why it should connect to the database every single time that it is called so how would i go about make a class variable that's the same in all the instances and once it is given the pointer, it won't create it again.

Thanks

Upvotes: 1

Views: 141

Answers (3)

tereško
tereško

Reputation: 58444

Instead of making new connection for each class you create, you should create a single connection an share it between the classes.

$connection = new PDO( ... );

$first = new Foo( $connection );
$second = new Bar( $connection );

In this way both instances have access to the same connection.

You also might benefit from watching this video: The Clean Code Talks - Don't Look For Things!

Upvotes: 0

Thomas Clayson
Thomas Clayson

Reputation: 29925

Hi you have two options.

Your best bet is creating a singleton class. This is a class which references itself so that you can never create more than one of it. If you try to create more than one of it it will return the currently initialised version of itself.

Otherwise stick with what you have and just make sure you're not calling new every time.

e.g.

$db = new Database(); // call this once to create
// don't do this again
$anotherdb = new Database();
// just use the db object from before
$db->query("...");

However this might get confusing, and you might lose scope of the variable, so I would suggest going with the singleton method. Some people will tell you not to use singleton's but its up to you. Works well with database classes.

If you look around on the internet you will find examples of other database classes to look at.

Have a look at frameworks like codeigniter too, they use their own database classes. It might be worth looking at how they work.

Upvotes: 2

Madara's Ghost
Madara's Ghost

Reputation: 174947

Database connection shouldn't go in the constructor. You should have a ConnectionFactory class, which would connect do the database and return a new DatabaseConnection object.

<?php

class ConnectionFactory {
    public static function newConnection($credentials) {
        //Connect to database
        $connection = new PDO(/* Credentials */);
        return $connection;
    }
}

$connection = ConnectionFactory::newConnection(CREDENTIALS);

Upvotes: 2

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