PHP extending class properties

I have two classes in a PHP application, B extending A for example. Class A has a function which returns some of its other properties in the form of an array of SQL insert queries eg

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 开发者_JAVA技巧a similar (identical) function which does the same thing for class B's properties, whilst still maintaining the values from class A. The idea being that each query will be passed through a final function all at the same time ie:

$mysqli->query("START TRANSACTION");
foreach($queries as $query) {
if(!$mysqli($query)) {
$mysqli->rollback();
}
}

IF all OK $mysqli->commit();

What would be the simplest way to achieve this? Any advice and ideas appreicated. Thanks!

Within B::queries() you can call the parent's implementation of that method and append 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 might (also) want to look into an ORM library like e.g. doctrine.

Use a getter function to grab the properties in queries(). In each class you can then control what values the queries function is using.

You can't really carry over stuff from one instance to another without initializing the newer class with the other instance's information. So you can extend A to change B's query function contents, then initialize B with an A instance:

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 query function), just clone A: $a = new A(); $b = clone $a;

so you want to use the properties in class A and class B? you can do this by using parent. in class B:

function queries(){
  $queries = array()
   //stuff to get queries

  return array_merge($queries,parent::queries());
}