[Deprecated] DMZ 1.5.3 (DataMapper OverZealous Edition)

[eluser]OverZealous[/eluser]
[quote author="introvert" date="1253752821"]Isnt it better to just use $_POST instead of writing array with each of the values?[/quote]

First, it's almost never better to use $_POST directly. The $_POST array is not very secure. An unscrupulous hacker can send anything to the $_POST array, so you always need to verify that you are not getting sent something bad.

Also, is it neccessary to call save at the end - it doesnt seem to be when I test it..

update does not do what you think. You need to look at the documents again. update is used to update multiple models at the same time, and should not be used for single object changes. It bypasses all of the built-in validation and checks that DMZ provides. It should never be used to update based on unchecked values, as this can potentially corrupt relationships in the database.

Instead, you want to set the fields directly and update the object. However, you can do this very easy using the built-in Array extension. Examples and an explanation are there, but it looks like this:

Code:

$object = new ObjectType();
$object->get_by_id($this->input->post('id'));

// only necessary if the extension isn't already loaded
$object->load_extension('array');
$object->from_array($_POST); // from_array does checking, and only sets fields that exist on the object itself.  See docs.

if($object->save()) {
    // success
} else {
    // Invalid, report errors to user
}

The documentation has plenty of examples, and lots of code to work from. Please take the time to read through it all. There are examples on your other question, including querying deep relationships, which will help you make easy queries based on objects that are many levels deep.