CODEWITHSUNDEEP
phpmysqlpdo
Andres SK
Andres SK

Reputation: 10974

Reusing database connection object

I'm using this function to connect to my MySQL db when needed, and also to re-use the same connection object for any further query I might need in the same php script.

function cnn() {
    static $pdo;
    if(!isset($pdo)) {
        try {
            $pdo = new PDO('mysql:host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS);
            $pdo->setAttribute(PDO::ATTR_TIMEOUT, 30);
            $pdo->setAttribute(PDO::ATTR_PERSISTENT, true);
            $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            $pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);
            return $pdo;
        } catch(PDOException $e) {
            http_response_code(503);
            echo $e->getCode.': '.$e->getMessage();
            die(); //or whatever error handler you use
        }
    } else {
        return $pdo;
    }
}

First query (object is created)

echo cnn()->query('SELECT firstname FROM user WHERE id=4;')->fetch(PDO::FETCH_COLUMN)

Second query (object is reused)

echo cnn()->query('SELECT title FROM news WHERE id=516;')->fetch(PDO::FETCH_COLUMN)

Do you agree on this approach? Do you think it can be optimized? Thanks for your opinions.

Upvotes: 4

Views: 2966

Answers (1)

Your Common Sense
Your Common Sense

Reputation: 157862

I agree with the method, though many people will tell you that this "singleton" approach is bad, bad.

However, I disagree with your implementation. It should be:

function cnn() {
    static $pdo;
    if(!$pdo) {
        $conf = array(PDO::ATTR_TIMEOUT => 30,
                  PDO::ATTR_PERSISTENT => true,
                  PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                  PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_OBJ,
            );
        $dsn = 'mysql:host='.DB_HOST.';dbname='.DB_NAME;
        $pdo = new PDO($dsn, DB_USER, DB_PASS, $conf);
    } 
    return $pdo;
}

Also, it looks sensible to move handler code into handler (and of course without echoing the error unconditionally!)

function my_exceptionHandler($exception) {
    http_response_code(503);
    if (ini_get('display_errors')) {
        echo $e->getMessage().$e->getTrace();
    } else {
        log_error($e->getMessage().$e->getTrace());
    }
    die(); //or whatever error handler you use
}
set_exception_handler("my_exceptionHandler");

Also, I'd extend it to accept a parameter to make several connections possible.

Upvotes: 3

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