The function qStr() takes an input string, and allows it to be:

1. Wrapped in single quotes.The value can then be used, for example in an SQL statement.
2. Have quotes inside the string escaped in a way that is appropriate for the database. This is done wherever possible using PHP driver functions e.g. MySQL real_escape_string.

$string = "Patrick O'Reilly";
 
$SQL = "SELECT * FROM names WHERE name='$string'";
 
$result = $db->execute($SQL);
 
/*
 * Execution fails  due to mismatched ` characters
*/
 
$qString = $db->qStr($string);
 
/*
 * function returns 'Patrick O\'Reilly' (The resulting string is database-specific)
*/
 
$SQL = "SELECT * FROM names WHERE name=$qString";
 
$result = $db->execute($SQL);
 
/*
 * Execution succeeds
 */