How to get users (entities) for a certain field value?

Question

I want to write a function that returns users which have entered a certain value to a custom user field.

Lets say there is a custom birthday field for every user. What would be the best way to get all users with a certain birthday?

I could create a DB query that searches the field_data_field_birthday table and returns the entity_id(s) (which in this case would be the users id(s)) for which the field_birthday_value matches a given value and then load the user(s).

This seems a little bit crude, are there generic functions for this use case available? In the entity API or the field API maybe?

Answer 1

Simple example for the use case I asked about:

$query = new EntityFieldQuery();
$query->entityCondition('entity_type', 'user')
  ->fieldCondition('field_birthday', 'value', $birthday);

$result = $query->execute();
$users_ids = array_keys($result['user']);