Question

I’ve seen several examples on the Net using a similar approach but I cannot see why it’s failing here.

I’m trying to use 2 parameters for DB_HOST and DB_DATABASE that I want to append to a string and assign it to the following variable:

External PHP file:

define( 'DB_HOST',         'localhost');
define( 'DB_DATABASE',     'mydb');

class Database {
private static $dsn = 'mysql:host=' .  DB_HOST . ';dbname=' . DB_DATABASE;
...
}

I’ve tried with single quotes, double quotes, and everything I can think of but I’m getting the following error:

Parse error: syntax error, unexpected '.', expecting ',' or ';'

I’ve tried putting the define( ‘DB_HOST’, ‘localhost’); inside the class as well (althogh this won’t be ideal, just for testing purposes) but then I’m getting:

Parse error: syntax error, unexpected T_STRING, expecting T_FUNCTION

Any idea what could be going wrong?

PS: I tried as well with normal PHP variables (as in $db_host) without any success either :S

Answer 1

You can’t initialize properties like that, you can only initialize them to a constant value. Even this would give the same error:

class Sample {
   private static $dsn = 'a' . 'b';
}

You’ll need to initialize it somewhere else. For example:

define( 'DB_HOST',         'localhost');
define( 'DB_DATABASE',     'mydb');

class Database {
private static $dsn;
    public static function setup() {
        self::$dsn = 'mysql:host=' .  DB_HOST . ';dbname=' . DB_DATABASE;
    }
}

Database::setup();