Copying Persisted Objects

Propulsion’s generated Active Record classes provide a copy() method to duplicate a mapped row in the database. Propulsion does not override PHP’s built-in __clone() — that stays available if you need a local, in-memory duplicate of an object that still maps to the same persisted row.

By default, copy() performs a shallow copy: any foreign key references on the copy remain the same as on the original.

<?php

$a = new Author();
$a->setFirstName('Aldous');
$a->setLastName('Huxley');

$p = new Publisher();
$p->setName('Harper');

$b = new Book();
$b->setTitle('Brave New World');
$b->setPublisher($p);
$b->setAuthor($a);

$b->save(); // so that auto-increment IDs are created

$bcopy = $b->copy();
var_export($bcopy->getId() == $b->getId());       // false
var_export($bcopy->getAuthorId() == $b->getAuthorId()); // true
var_export($bcopy->getAuthor() == $b->getAuthor());     // true

Deep copies

Calling copy(true) makes Propulsion create a deep copy of the object. “Deep” here specifically means the objects that reference this row through a foreign key (its fkey referrers, e.g. a Book’s Review rows) are copied too, rather than shared by reference — it does not mean the row’s own foreign key columns get new related objects. A Book’s author_id/publisher_id columns are copied verbatim by copyInto() regardless of $deepCopy, so the copy still points at the same Author/Publisher row either way.

Continuing the example above:

<?php

$bdeep = $b->copy(true);
var_export($bdeep->getId() == $b->getId());             // false
var_export($bdeep->getAuthorId() == $b->getAuthorId());       // true
var_export($bdeep->getAuthor() == $b->getAuthor());           // true