14.03.2016 10:41, liviuslivius wrote:

> Why?
> Index is a Tree? And if i found VALUE 2 in A key then i can fast find
> value 5 in sub key (leaf)
> You scan throught keys in A, and then in finded nodes you look for leafs
> in B

Compound index key is a single concatenated value, not two separate
ones. You may search for exact match {2, 5} or for its "substring" {2}.
You cannot get the second segment from the key as independent value.
Firebird indices are imprecise and generally you may convert value->key
but cannot key->value.


Dmitry