[Xesam] Relative date queries / Mono XESAM library
Mikkel Kamstrup Erlandsen
mikkel.kamstrup at gmail.com
Tue Jan 15 00:34:20 PST 2008
On 15/01/2008, Gabriel Burt <gabriel.burt at gmail.com> wrote:
> Hello all,
> First a question:
> What is the best way to support relative date queries in XESAM? For
> example, in Banshee people will have smart playlists such as "songs
> not played in the last 2 hours." This is turned into a SQL query
> similar to "LastPlayed < now() - 7200". The user query language form
> of this would ideally be "played < 2 hours ago", but what of the XML?
> What do you think of an optional 'relative' attribute on the date
> value specifying the seconds to add to the date, and allowing 'now' as
> a valid date?
> <field name="lastplayed" />
> <date relative="-7200">now</date>
It was very briefly discussed a good while ago (perhaps only on IRC)
if we should have predefined time values ie $now, $yesterday, etc, but
it was turned down as needles complication at the current point. This
does not mean that we will never have it, but we should keep focus on
getting a clean core spec to start out with.
> Now the announcement:
> In Banshee we recently rewrote our query code and tried to make it
> compatible with XESAM. It includes two parsers (user query language
> and XML) and methods to produce user query language, XML, and SQL.
> The code is here:
> It's in a namespace/assembly that is not specific to Banshee, so
> Mono/.Net-based apps should be able to reuse it easily. The user
> query language is very similar to XESAM's, but also allows | and comma
> for or, NOT for -, and ()'s for grouping/nesting. We have some
> preliminary documentation up at:
Uh, super sweet!
I actually think it is a nice idea to extend the user search language
because it has been designed to be as simple as possible. If people
experiment a bit we can have a better foundation to make decisions on
if we ever want to expand the core Xesam user search language.
When you say that you support the XML query language does that mean
that I can somehow send Xesam queries to Banshee (fx via a Xesam dbus
interface or other) or that you use it for stored searches..?
There seem to be a lot of C# Xesam integration going on these days;
Beagle, Nemo, and Banshee. I wonder if they are coordinated in any
way. Feel free to use the Xesam list to do so if you guys want.
And as I say to everyone, if you have any comments on any other parts
of the spec, be sure to chime in. 1.0 is closer every day.
Cheers and gongrats,
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