[SQL] emulating sub-queries and search prformances

[Antoine Beyeler]

> Antoine, it seems you use C++. So
>
> 1) why you not use BitSet class?
> yes, it can be little more work for you, but result may surprise you!
>
> 2) again, when you do
>
>     BitSet1 = do search on 'old'
>     Bitset2 = do search on 'man'
>
>     bitset3 = BitSet1 intersection BitSet2
>
> Now you can SELF iterate found 199 records and check them on 'old 
> main'.
> Also you can use here Formula to iterate records of bitSet.
>
> Try this.
>

I'm working with VDK_Text method, and I couldn't find how to obtain a 
BitSet with a one word index based query.

	bitSet = text.Find("MAN");
	bitSet->GetCount();

gives 0 results, while

	bitSet = text.SearchLike("MAN");

gives the correct amount of result, but is very slow since it is not 
index based.

With VDK_String, "Find" is working well. In short, the "Find" function 
seems not to be implemented in VDK_Text, which is a major problem  for 
me. Can you think of a workaround??

Best regards,
Antoine Beyeler