Connect to an external db

Sometimes it is useful to use another database than the one installed by default by Drupal.
1. Declare the database in settings.php
the entry default / default is created by Drupal (no idea why it is 2 times default...)

$databases = array (
  'default' =>
  array (
    'default' =>
    array (
      'database' => 'drupal_db',
      'username' => 'xxx',
     ...
    ),
  ),
  'myotherdb' =>
  array(
    'default' =>
    array (
      'database' => 'my_snippet',
      'username' => 'xxx',
     ...
      ),
  ),
);

2.then in a module use db_set_active() function to switch from database.

db_set_active('myotherdb');
db_query("select snippet_nid from xx");
db_set_active();

Display errors - WSOD

The bootstrap override the values you could set to display error ad the reporting level. To be 100% sure everything is printed out when something fails in a blank screen (wsod), make index.php like this:

Properly render a field

Drupal offers a few (sometimes complicated...) solutions to output a field. Lets take an example with a date field.
To display the full rendered field: field_view_field()