Re: general design issue

On 23 Kwi, 17:13, paul c wrote:
> Btw, Sqlite did use an index for 'select a from text where a > 'a190'
> and a < 'a195'.  Lots has been written about algebraic optimal
> conversions of relational operators but very little about formal
> conversions of type manipulations like this and many other situations.
> Too bad, this would have been more worthwhile for the SQL committee to
> have spent their time on than arguing about keywords and trying to make
> their informal definiitions precise. .It's pretty bad when a single
> implementation can't even make consistent optimizations for a
> single-table query.  No slur against sqlite per se, there are things I
> like about it.  I'll bet all the popular sql implementations are similar
> when it comes to optimizations/separating logical from physical.

well, if i cannot use substr/like with sqlite because of bad performance what about my original solution with second table keeping prefixes and integer with one bit per letter.

how to make it fast and small? is it feasible at all? Received on Thu Apr 23 2009 - 21:39:14 CEST