Jody and Andrea,
Thank you for your helpful comments and thoughts on this. I will discuss this
with Ian again and decide on a final strategy. I'd like to get something
working fairly quickly and I will keep you all up-to-date on progress.
Thanks,
Scott
********************************************* Scott Pezanowski
email: [email protected]
*********************************************
> Date: Wed, 28 Jul 2010 10:53:39 +1000
> Subject: Re: [Geotools-gt2-users] dynamic text search queries in postgresql -
> tsvector column type
> From: [email protected]
> To: [email protected]
> CC: [email protected]; [email protected];
> [email protected]
>
> I thought of suggesting that as well; was not sure how carefully he
> wanted to reflect the WFS Like definition.
>
> But yes that would work; good thinking.
>
> Jody
>
> Aside: I apologize for my original response sounding mercenary. I am
> not holding a solution hostage for money; I simply had thought through
> this process very recently and had some ideas on hand. I would be more
> then happy with anyone doing the work and submitting a patch for
> review (heck I would like to use the solution as well).
>
> On Wed, Jul 28, 2010 at 4:45 AM, Ian Turton <[email protected]> wrote:
> > On Tue, Jul 27, 2010 at 2:52 AM, Andrea Aime <[email protected]> wrote:
> >> Jody Garnett wrote:
> >>> I was actually thinking about this one for work last week. I had thought
> >>> to make a GeoTools search and function; and then adjust the sql encoder
> >>> to encode it if the textsearchable_index_col is a match. That is kind of
> >>> where my thinking stopped; figured I would talk to justin about it if I
> >>> get paid.
> >>>
> >>> An alternative is aaime's recent work allowing you to define your own
> >>> SQL "view".
> >>>
> >>> I do not recommend extending filter or like filter (since it represents
> >>> a controlled data structure that must be emulated on WFS, SQL, shapefile
> >>> etc...).
> >>>
> >>> The filter data structure is however extendable in two ways:
> >>> - functions (you can define your own functions as above)
> >>> - property accessors (you can teach the filter to work on more kinds of
> >>> content then just features)
> >>>
> >>> The interesting question for me is how the internals of the JDBC-NG
> >>> datastore's handle encoding a filter into SQL; and if there are any
> >>> hooks already defined which you can use to teach it how to handle
> >>> specific functions.
> >>>
> >>> There is a dialect object which contains all the database specific work
> >>> in one spot; when I last looked the code responsible for doing the
> >>> SELECT statement was duplicated a few times but that could be fixed to
> >>> recognise a specific "function encoding" opportunity.
> >>
> >> The sql encoding is not done by the dialect, but by a FilterToSQL
> >> subclass, each specific for a database.
> >> There you could recognize a function and encode it.
> >>
> >> The tricky part is that to do it properly, to make the function
> >> something worth contributing back to geotools, it should be able
> >> to work stand alone in memory as well. Otherwise we end up with
> >> a function that actually just work against PostgreSQL.
> >> Which... well... might be acceptable too, if it's documented
> >> very clearly.
> >
> > My suggestion to Scott was to extend the way the PostGIS datastore
> > encoded a like filter if the column it was against was a TS_Vector to
> > use @@ instead of like. For an end user there would be no difference
> > (except for a speed up if available). If other databases provided a
> > similar function they could be extended in a similar way.
> >
> > For shapefiles and memory stores it might be worth leveraging Lucene
> > but to be honest I'm not sure that people should be considering that
> > sort of query against large shapefiles etc.
> >
> > Ian
> > --
> > Ian Turton
> >
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