Emilio Astarita wrote:
> Hi people,
>
> I want a class that allows create objects that get the information
> consulting the DB. So, I am thinking to do something like this:
>
> class element {
> public __construct($id,$type = 'id') {
> switch($type) {
> case 'id':
> $where = sprintf(" id = %d ",$id);
> break;
> case 'name':
> $where = sprintf(" name = %s ",escape($id));
> break;
> //...
> // get the row and call setName($row['name'])...
> }
> }
> }
>
> This works fine, but also I want a good way (efficient) of getting a
> collection of these objects. I can't figure a convenient way. A static
> function its a good posibility? I have some ideas but they imply public
> setters of the class `element'.
>
> Thanks for any help.
>
A static method should still be able to set values of private members. I do
something like:
class Element
{
private $id;
private $name;
public __construct()
{
// Do general construction tasks...
}
public static bulkLoad($id,$type='id')
{
$ret = Array();
$sql = 'SELECT id,name FROM Table ';
switch ($type)
{
case 'id':
$sql .= 'WHERE id ILIKE $1'; // Use ILIKE to allow for wildcards
break;
case 'name':
$sql .= 'WHERE ILIKE $1'; // Use ILIKE to allow for wildcards
break;
//...
}
$params = Array($id);
// I use postgreSQL parameterised queries a lot - saves lots of quoting etc.
// Note: NO ERROR CHECKING in this example...
$data = pg_fetch_all(pg_query_params($sql,$params));
foreach ($data as $row)
{
$elem = new Element(); // No-args constructor
$elem->id = $row['id'];
$elem->name = $row['name'];
$ret[$id] = $elem;
}
return $ret;
}
}
Then you get an array of elements which match the (possibly wild-carded)
condition, indexed by the element Id (useful for making HTML <select> lists, for
example).
In fact, I have a base class which implements this by class introspection -
filling the properties of objects which extend it by mapping them to the
database fields...
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Developer fax: 01580 893399
Justcroft International Ltd., Staplehurst, Kent
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