I tried to grant execute permission for stored procedures for a role.
but when this procedure is executed by a user in this role I get
message, that rights doesn't exist on table.

I see in IBExpert DDL that grant select on tables used by that procedure
are already given to the stored procedure.

Question: is it sufficient that I grant a role to a proceudure? or
should I grant that role also rights for each individual table as well?

application does all access to data though stored procedures. so in
reality users should not need to be granted rights on tables. how would
be best practice to solve it?