Demonstrate how to Update/Upgrade the Node Example module

It would be a plus to demonstrate upgrading and updating. I have started a discussion on this in #1699440: A dedicated to module to demonstrate hook_update_N() and automatically testing upgrades and updates

hook_installed_fields() and hook_installed_instances() are part of the EntityAPI API, as opposed to the Entity API. :-)

That is, not the core entity API, but the contrib Entity API.

But yah, an example of how to add/remove fields during an update would be great.

This would be extremely helpful to me as well. After searching for a while, I still haven't come up with a way of doing exactly what you're trying to do. Uninstalling and re-installing with the extra fields is out of the question for me, because there's just too much data already there. Did you find any information to help you with your quest?

Edit: I think I figured out how to add a simple field to my already existing node. (I got my code mostly from this comment.) Since I don't need to update any existing nodes, there's no $sandbox for multipass updating. Not sure whether I'm following best practices, but here's my code (in the module's install file) in case it helps someone:

/**
 *
 * Add "my_new_field" field to "my_exising_node"
 *
 */
function my_module_update_7001() {
  // just checking whether field is already there:
  if (!field_info_field('my_new_field')) {
    $new_field = array(
      'field_name' => 'my_new_field',
      'cardinality' => 1,
      'type' => 'text',
      'settings' => array(
          'max_length' => 255,
      ),
    );
    field_create_field($new_field);

    // Create the instance on my content type (bundle):
    $new_field_instance = array(
        'field_name' => 'my_new_field',
        'entity_type' => 'node',
        'bundle' => 'my_exising_node', // this is the name of the content type I already created with pre-existing fields
        'label' => 'My new field label',
        'widget' => array(
          'type' => 'text_textfield',
        ),
    );
    field_create_instance($new_field_instance);
    
    // debug message:
    drupal_set_message($message = t('The new field has been installed successfully.'), $type = 'status');
  } else {
    drupal_set_message($message = t('No field has been installed'), $type = 'status');
  }
}

Before you attach, you'd really also want to check that the node type exists, with node_type_get_type().

Then check that the field isn't already attached with field_info_instance(). Also use this function to verify that it's been attached after you attach it.

We really should have an example module for attaching and removing fields. Then people could just copy those techniques into their updates.

Any volunteers to write it? :-)

Hmm. As it turns out, it was me.

Node Example shows you how, in node_example_node_type_insert(): http://drupalcode.org/project/examples.git/blob/HEAD:/node_example/node_...

It would be great if someone wanted to finish the job and incorporate this into an update/upgrade process, with tests.

I'm going to call this fixed, because node_example_node_type_insert() shows us how to add fields.