field_ui_field_overview_form_submit($form, &$form_state) Form submission handler for field_ui_field_overview_form(). Read more about field_ui_field_overview_form_submit($form, &$form_state)
field_update_instance($instance) Updates an instance of a field. Read more about field_update_instance($instance)
_field_write_instance($instance, $update = FALSE) Stores an instance record in the field configuration database. Read more about _field_write_instance($instance, $update = FALSE)
