Question

I have a class for each database table object. Each class takes care of connection/queries/data format (database table specific logic) as I prefer to assign a connection for each class for better modularity. Also, I am using specific connections for some tables and queries.

My question is how can I check if a connection already exists so it won’t start another one?

Basically I want to check if the connection with the same username/password/database has already been made. Or is this not necessary because mySql won’t start a new connection for the same user? If that is so then please explain.

After further research found out that this is not possible … it would require to get the thread id and use the conn with the thread id and it would act like a persistant conn; Or it would require to keep track every thread ids used during a script and it’s kinda useless.

There isn’t yet a spimple method of doing this … persistant connection can be a choice but then u have to take care of connection clean up and again sux 🙂

P.S. : Eventually i did made a tracking system for the connections during my app run (the guys that said to store them in a globally available object we’re right). Stored conn object and conn params in 2 arrays in a singleton class object, checked if the params allready exists in params array , if not make new conn , if yes get the conn object from the array-key thats the same with the key where params were found… I allready had the arhitecture made for this but didnt want to use that class…not the logic i began with :), and also wanted to make it in a library item, thats why i was looking for a simple and abstract solution but there is only a particular solution 🙂

Answer 1

• Create new connection for each class is not a good idea. It may be modularized to you but your mysql server will be soon bloated with too may connections error.

I suggest use singleton pattern and some OO.

class Singleton{
    private static $instance=null;
    public function connection(){
        if(self::$instance==null){
            self::$instance = mysql_connect(); // define it in your way,
        }
        return self::$connection;
    }
}

class TableA extends Singleton{
    function find($id){
        $query="select * from `A` where `id`='$id'";
        mysql_query($query, $this->connection());
        ... // other codes
    }
}