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Note to self: take another look at PostgreSQL and its XML support. It’s looking pretty tasty…

PostgreSQL and XML updated

I’m playing around with XQuery, and am finding it to be quite powerful. Still getting my head around the FLWR syntax, and what I can do with that, but initial pokings are quite promising. Thanks a LOT to Leif and Jim at Bluestream for guiding me through the first steps. Their XStreamDB is quite a nice XML database, and handles XQuery natively.

Anyway, here’s the query that has evolved from the first early steps. It pokes through the XML database for all documents that contain a <langstring></langstring> element, and returns a set of elements describing some stuff I’ll need to display the item in a search result page.

FOR  IN Root("RepositoryDB:LOM")
WHERE
	MATCH  USING [//*:langstring CONTAINS "biology"]
RETURN
	LET XQuery explorations := /*:lom/*:general/*:title/*:langstring/text()
	LET  := /*:lom/*:general/*:description/*:langstring/text()
	LET  :=/*:lom/*:technical/*:location/text()
	LET  := /*:lom/*:technical/*:format/text()
	LET  := GetDocumentId()
	LET  := /*:lom/*:lifecycle/*:contribute/*:centity/*:vcard/text()
	LET  := /*:lom/*:metametadata/*:contribute/*:centity/*:vcard/text()
RETURN
<lo_result>
  <objectid>{}</objectid>
  <title>{XQuery explorations}</title>
  <description>{}</description>
  <location>{}</location>
  <format>{}</format>
  <contributor>{}</contributor>
  <owner>{}</owner>
</lo_result>

I’m playing around with XStreamDB, and am really impressed with it so far. Relatively fast queries, doing stuff that would bring our current metadata database to its knees.

One thing I’m realizing is that I’m a complete dumb newbie when it comes to XQuery. Sure, I understand some of the concepts, but implementing the queries and the syntax etc… is a bit much right now. I’m working on that, to be sure, but there seems to be a big gaping hole on the ‘net (and the bookstore) on decent, usable XQuery documentation.

Sure, there’s the W3C language spec. but who really reads that (or, if you read it, do you really understand it?)

Has anyone come across some comprehensive, well-thought-out, and practical XQuery guide/documentation?

Here’s all I’ve come across:

Surfing the blog world with Feedster, and have come across a few more XML database links:

Berkely XML DB by Sleepycat sounds interesting. Has no mention of XQuery, though, which is a big drawback for our needs… (here’s a development weblog for their xml database)

NeoCore XMS sounds great, but rather pricey (advanced XQuery, integrated XSLT, etc…)

Here’s a thread on Slashdot about Open Source XML Databases… The thread includes this link to a weblog about xml databases, but it seems rather dated (last post was Aug 2002).

HitSOFTWARE claims their jAllora product to be a relational-to-xml mapper (and vice versa). Geert Clememsen from Frontbase just sent a message saying it works with the FrontBase database server.

Sounds interesting. Didn’t see any claims of XQuery support though (the closest they come to mentioning support is in this white paper, which doesn’t come right out and say they support it, only that they should). Will have to dig deeper. It’s also a little pricey. It’s good that it’s java, and has lots of tools, but it’s bad that it requires a separate webservice provider to manage/interact with it (ala Tamino) – an integrated solution like XStreamDB would be nicer for our needs.

One more product to add to the list for further study…

Mike just got back from Vancouver, and was talking about an XML database he saw there: Bluestream XStreamDB

They claim to support XQuery via JDBC somehow. It’s a java-based solution (i.e., portable – that’s a Good Thing). I’m downloading it now to see what it does. Looks VERY promising.

Details available here.

UPDATE: Wow! It worked right off the bat! First XML DB to do THAT for me… And it comes with a whiz-bang management app, too! So far, much more impressed with XStreamDB than anything else I’ve tried… Oh, and it’s not just portable, it’s EMBEDDABLE. We could conceivably embed the jars for XStreamDB INSIDE CAREO for the repository in a box. It doesn’t come easier than that!

A couple more XML databases for the list:

X-Hive
Ipedo

Both claim to support multiple simultaneous xml schemas, XQuery, and lots of other goodness. Both claim to be relatively portable (although they don’t list MacOSX as a supported platform. ARGH! They both list Solaris and Linux, so maybe that’s close enough?) Both carefully hide what it costs to license their software.