Upgrade to Lion -- why Valentina has columnar format ...

Bob Sneidar bobs at twft.com
Thu May 31 14:35:31 EDT 2012


Yes, but it is my understanding of SQL that a query on a non-indexed column will create a temporary index in mySQL and maybe others. I might be wrong about that. But Foxpro does not do that. In fact if you set a filter or seek using a FOR statement that has no indexed columns or has some non-indexed columns, Foxpro will proceed at a reduced speed without any temporary indexing. 
Of course, you could index all columns that you will ever search on, but this is not always the best, because depending on the application, many columns may only occasionally be searched, and the overhead of updating all those indexes becomes counter-productive in terms of speed overall. So the principle of indexing columns that you search often, as you stated is the real life standard for indexing imho. 

Bob


On May 31, 2012, at 11:19 AM, Ruslan Zasukhin wrote:

> On 5/31/12 8:14 PM, "Bob Sneidar" <bobs at twft.com> wrote:
> 
>> Foxpro does, but it's slow.
> 
> You mean that foxpro can do
>    search on column that is not indexed ?
> 
> Well, of course each db engine can do this.  :-)
> And Valentina, and Light, and mySQL, ...
> And yes it is much slower than indexed search,





More information about the Use-livecode mailing list