Best method of connecting to a database (Multiple Queries)

Lately I seem to have been having a few problems with my PHP app. Every now and then the logs would show "Not enough database connections". Recently the errors have been more like "Not enough memory".

I realised today what the real problem was and was wondering what people thought about it.

The problem that I had seems to be caused by having more than one query connected at a time. My most used database code goes something like this:

(Although I am using Zend Framework style here it should not matter)

$stmt = $db->query($sql);
while ($row = $stmt->fetch()) {
    $someClass->method($row['title']);
    echo $row['title'];
}

Code (markup):

But then in $someClass->method I would be doing more database stuff.

function method(){
    while ($row = $stmt->fetch()) {
        echo $row['somethingelse'];
    }
}

Code (markup):

Now here are my questions:
- Am I right, assuming that every separate SQL query (connected at the same time) requires it's own database connection?
- Do multiple database connections use a significant amount of memory?
- Has anyone else hit this?
- Does anyone have another way of coding this?

The code by the way was fixed by getting all the data from the SQL query at once, so that I did not need to be fetching from the database every loop. Something like this:

$stmt = $db->query($sql);
$allData = $stmt->fetchAll()
foreach( $allData as $rows){
    $someClass->method($row['title']);
    echo $row['title'];
}

Code (markup):

 

Unless there's some major issues with the connection class, in your examples, there should only be a single connection. Normally it would work like this:

Connect to database ->
Query as many times as you want.....
Close connection

If not coded correctly, it could be doing this:
Connect to database->
Query once
Close connection
...Repeat

Did you code the connection and querying class yourself. You should definitely be using a singleton database class which will prevent multiple connection on a single script.