PDOException - saving a page when not all fields are filled in.

Tested with:
Drupal: 7.15
PHP: 5.3.14
Webserver: Apache
Modules enabled: Display Suite, Media, Jwplayer, Ctools, libraries.
Language: dutch, first day: monday, Timezone: Europe/Berlin

1. Created a content type: page.
2. Added rijksvideo widget/field.
3. Field is set "not required"
4. Created new page
5. Used the option to manual fill in the fields. and not the XML.
6. Putted some video urls in het video fields
7. Left the other fields blank
8. safe

PDOException: SQLSTATE[HY000]: General error: 1366 Incorrect integer value: '' for column 'field_rijksvideo_date' at row 1: INSERT INTO {field_data_field_rijksvideo} (entity_type, entity_id, revision_id, bundle, delta, language, field_rijksvideo_xml, field_rijksvideo_movie_webm, field_rijksvideo_movie_webm_size, field_rijksvideo_movie_mp4, field_rijksvideo_movie_mp4_size, field_rijksvideo_movie_mp4hr, field_rijksvideo_movie_mp4hr_size, field_rijksvideo_caption, field_rijksvideo_audio, field_rijksvideo_thumbnail, field_rijksvideo_transcription, field_rijksvideo_duration, field_rijksvideo_date) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6, :db_insert_placeholder_7, :db_insert_placeholder_8, :db_insert_placeholder_9, :db_insert_placeholder_10, :db_insert_placeholder_11, :db_insert_placeholder_12, :db_insert_placeholder_13, :db_insert_placeholder_14, :db_insert_placeholder_15, :db_insert_placeholder_16, :db_insert_placeholder_17, :db_insert_placeholder_18); Array ( [:db_insert_placeholder_0] => node [:db_insert_placeholder_1] => 32 [:db_insert_placeholder_2] => 32 [:db_insert_placeholder_3] => page [:db_insert_placeholder_4] => 0 [:db_insert_placeholder_5] => und [:db_insert_placeholder_6] => [:db_insert_placeholder_7] => [:db_insert_placeholder_8] => [:db_insert_placeholder_9] => [:db_insert_placeholder_10] => [:db_insert_placeholder_11] => [:db_insert_placeholder_12] => [:db_insert_placeholder_13] => [:db_insert_placeholder_14] => [:db_insert_placeholder_15] => [:db_insert_placeholder_16] => [:db_insert_placeholder_17] => [:db_insert_placeholder_18] => ) in field_sql_storage_field_storage_write() (regel 448 van /Users/......./......./[drupal-root]/modules/field/modules/field_sql_storage/field_sql_storage.module).