Question

I’ve some reusable code which depend on the presence of some database. So I need to ensure in my lib that a database exists. What’s the right method to do it ?

I was thinking about having a class that would setup the tables if they’re not present. Is there any good known design pattern or method to use ?

PS : I’m using ZF 1.

EDIT : By correct, I’m intending what we, programmers, put behind correct : elegant, which means : reusable, configurable, platform independent, few dependencies, low coupling.

EDIT : after the first comments and answers, I’ve changed that very poor choice of word “module” to “library”.

Answer 1

I would just create a single class like this:

class My_SchemaChecker
{
    // db adapter
    protected $db;

    public __constructor($db)
    {
        $this->db = $db;
    }

    public function ensureSchemaExists()
    {
        if (!$this->doesSchemaExist()){
            $this->createSchema();
        }
    }

    protected function doesSchemaExist()
    {
        // check that tables, etc exist
    }

    protected function createSchema()
    {
        // issue queries to create desired schema
    }
}

Usage is:

$checker = new My_SchemaChecker($db);
$checker->ensureSchemaExists();