 alter table VIGILANT_GROUP modify BEGIN_OF_FIRST_PERIOD_FOR_UNAVAILABLE_PERIODS datetime;
alter table VIGILANT_GROUP modify END_OF_FIRST_PERIOD_FOR_UNAVAILABLE_PERIODS datetime;
alter table VIGILANT_GROUP modify BEGIN_OF_SECOND_PERIOD_FOR_UNAVAILABLE_PERIODS datetime;
alter table VIGILANT_GROUP modify END_OF_SECOND_PERIOD_FOR_UNAVAILABLE_PERIODS datetime;
 