[Xapian-discuss] Understanding omindex and scriptindex

[Olly Betts]

On Tue, Nov 01, 2005 at 06:28:10PM +0100, Gilles Polart-Donat wrote:
>  I see there are some differences in the work made by omindex and 
>  scriptindex. I think scriptindex add terms with a prefix to constraint the 
> query, but the way to do it is free for the user : he can add as many field 
> he needs, if it use them on query parameters. Omindex is more closed, with 
> no parameters, Right ?

Omindex doesn't currently index anything suitable for fielded searching.
It could index document titles and other metadata as separate fields but
doesn't currently.

> I saw there are two way to add information with a doc :
> - put a new line in set_data
> - add a new term in the document
> 
> How do we make the choice between these two ways ?

Do you want to be able to locate documents using this information?  If so,
make it a term.

Or do you want to be able to display (or otherwise use) this information
given a particular document?  If so, add it to the document data.

Sometimes you want to do both.  For example, you might want to be able
to filter searches on mime-type, and also use it to display a "filetype"
icon next to each search result.

> I saw a set_value method, but I don't understand (if | where) it is used on 
> a query.

Values allow you to sort results, perform non-boolean filtering, and
collapse multiple matches into one.

> Can omindex and scriptindex share the same database ?

Not usefully, in general.  But if you know what you're doing, I can see
special cases where using both on the same database could be usful.  For
example, you could use scriptindex to quickly delete particular
documents from a large omindex built database (say you have a court
order to remove certain material from a site...)

Cheers,
    Olly