PHP extending class properties
I have two classes in a PHP application, B, for example extension A. Class A has a function that returns some of its other properties as an array of SQL insert queries, for example
Class A {
$property_a;
$property_b;
$property_c;
$property_d;
function queries() {
$queries = array();
$queries[] = "INSERT INTO xxx VALUES " . $this->property_a . ", " . $this->property_b";
$queries[] = "INSERT INTO yyy VALUES " . $this->property_b . ", " . $this->property_d";
}
}
I would like class B to have a similar (identical) function that does the same for the properties of class B while keeping the values from class A. The idea is that every request will be passed through a final function all at the same time :
$mysqli->query("START TRANSACTION");
foreach($queries as $query) {
if(!$mysqli($query)) {
$mysqli->rollback();
}
}
IF everything is OK $ mysqli-> commit ();
What would be the easiest way to achieve this? Any tips and ideas. Thank!
Inside B :: queries (), you can call the parent implementation of this method and add your data to the array a :: queries () returns.
class B extends A {
protected $property_e=5;
public function queries() {
$queries = parent::queries();
// In a real application property_e needs to be sanitized/escaped
// before being mixed into the sql statement.
$queries[] = "INSERT INTO zzz VALUES " . $this->property_e;
return $queries;
}
}
$b = new B;
foreach( $b->queries() as $q ) {
echo $q, "\n";
}
But you may (also) want to look into the ORM library, for example for example. doctrine .
Use getter function to grab properties in requests (). In each class, you can control what values the query function uses.
You cannot transfer stuff from one instance to another without initializing a new class with information about other instances. So you can extend A to change the content of B's request function, and then initialize B with an instance of A:
class A {
protected $propa = "";
protected $propb = "";
//etc
function query { /*...*/ }
}
class B extends A {
function __construct( A $classA )
{
$this->propa = $classA->propa;
// etc
}
function query()
{
//B-type queries
}
}
$A = new A();
// set stuff in a
new B( $A );
If A and B are 100% the same (including the query function), then just clone A: $ a = new A (); $ b = clone $ a;
what would you like to use properties in class A and class B? you can do this using the parent. in class B:
function queries(){
$queries = array()
//stuff to get queries
return array_merge($queries,parent::queries());
}