How to integrate UUID with third party entities

When developing custom entity type and you need to integrate it with UUID module you need to do the following:

1. Mark your entity type in hook_entity_info() that it shall have UUIDs:
   

   
   /**
    * Implements hook_entity_info().
    */
   function mymodule_entity_info() {
     return array(
       'myentity' => array(
         'base table' => 'myentity',
         'revision table' => 'myentity_revision',
         // ...
         'uuid' => TRUE,
         'entity keys' => array(
           // Value here('uuid' after the '=>' sign) is the name of the column that will be used to store corresponding UUID in the database.
           'uuid' => 'uuid', 
           // In case you creating revisionable entity type you should also put this line.
           'revision uuid' => 'vuuid',
         ),
       ),
     );
   }
   

2. In your hook_schema definition you need to put the following:

     if (module_exists('uuid')) {
       $field = uuid_schema_field_definition();
       $schema['myentity']['fields']['uuid'] = $field;
       $schema['myentity']['indexes']['uuid'] = array('uuid');
       // This is needed only for revisionable entities.
       $schema['myentity_revision']['fields']['vuuid'] = $field;
       $schema['myentity_revision']['indexes']['vuuid'] = array('vuuid');
     }