Implicit vs. Explicit
Both the above are purely conceptual things and for Oracle engine, both are same. But implicit cursors are more efficient and easy to deal with.
Implicit
Explicit
begin
for x in ( select * from t )
loop
process x;
end loop;
end;
declare
cursor c is select * from t;
l_rec c%rowtype;
begin
open c;
loop
fetch c into l_rec;
exit when (c%notfound);
process l_rec;
end loop;
close c;
end;
/
Both these have no performance benefit over the other. But for explicitly defined cursors, there is more code that needs to be written and hence chances of programmatic errors are more.
