Event profile(s) field/table
Profiles are stored in civicrm_uf_group and the fields are in civicrm_uf_field. Search the column uf_group_type in civicrm_uf_group to see what the profile is used for or just lookup a particular profile id.

To search by an event id you will also need to look in civicrm_uf_join and use something like:

SELECT group_id where module = 'CiviEvent' AND entity_id = {my_event_id}