Quicker way of doing this - php

Question

I'm using PDO to get an array of relations from my DB.
$dbRelaties = $dbh->query("SELECT pkRelatieId,naam,email FROM relaties");
in another function i need to acces one specific row in this array. I've managed to do it like this:
$klant = array();
foreach($dbRelaties as $dbRelatie)
{
if($dbRelatie["pkRelatieId"] == $relatie){ $klant = $dbRelatie; break; }
}
sendMail("Subject",$klant);
The above code works. But i'me looking for a neater solution and a quicker one, the above code is called in a function and that function is called inside a loop. So everytime it executes is has to loop through $dbRelaties to get the correct relation.
Can anyone set me in the right direction?

Answer 1

assuming the pk means primary key, then
while($row = mysql_fetch_assoc($result)) {
$dbRelatie[$row['pkRelatieID']] = $row;
}
would produce an array keyed with your primary key field, so
$dbRelatie[$pk]['naam']
will give you that particular pk's naam value.

Answer 2

To show a PDO specific version of Marc B's answer.
Assuming a query was executed through PDO like so:
$sql = "SELECT pkRelatieId,naam,email FROM relaties";
$resultSet = $pdo->query($sql);
The results can be read into a PHP array using PDO's fetch method.
$dbRelaties = array();
while ($row = $resultSet->fetch(PDO::FETCH_ASSOC)) {
$dbRelaties[$row['pkRelatieID']] = $row;
}
This can then be used to access values based on the PK of the row.
sendMail("Subject", $dbRelaties[$relatie]['naam']);
Furthermore. PDO lets you assign a default fetch mode to each PDO instance, and the PDOStatement class is Traversable, so that you don't actually have to call the fetch() method in a while loop to go through a result set.
If you were to do this to a PDO object before a query: (Ideally only once right after creating the object.)
$pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
Then you can use a foreach loop on the result set to get row arrays with field names, instead of using a while loop.
$dbRelaties = array();
foreach ($stmt as $row) {
$dbRelaties[$row['pkRelatieID']] = $row;
}