create table A (ID integer not null primary key,
HOST_ID integer not null,
NAME varchar(30));

CREATE VIEW V_A(ID, HOST_ID, NAME)
as
select id, host_id, name from A;

CREATE OR ALTER VIEW V_A(ID, HOST_ID, NAME, HAVE_CHILDS)
as
select id, host_id, name,
case when exists (select * from V_A AA where AA.host_id=V_A.id) then 1 else 0 end
from A;

This operation is not defined for system tables.
unsuccessful metadata update.
STORE RDB$USER_PRIVILEGES failed in grant.
action cancelled by trigger (0) to preserve data integrity.
could not find table/procedure for GRANT.

GRANT EXECUTE ON PROCEDURE V_A TO VIEW V_A