I took my option (1) and now have my commit hooks ensure that the database exists, which was easy enough to do (just needed to add an addition CHECK command to my existing BaseX command sequence). It just means that the RESTXQ code itself can't ensure that the metadata database is up to date, at least not without some significant refactoring, which I probably need to do but don't have scope for at the moment.
The problem in my case with doing the create and add at once is that there is quite complex business logic involved in creating the documents, so they're not something that can be conveniently created, held in memory, and then committed at once (I could have implemented the processing that way but it's definitely not the natural way to do it). Basically I'm building a metadata cache to optimize queries that would be hard to do by brute force. The number of documents to be created and added could be quite large. As a cache you'd like to be able to have it created or updated on demand--e.g., if I request an operation that requires the cache, the first thing you do is see if the cache is up to date and, if not, create or update it. But with XQuery's constraint on when you can do updates that's not possible, at least not in a naïve way--if you have a function that needs to return a result it cannot also do updating (meaning it can't call any updating functions). I understand the reasoning for that restriction but it is an annoying constraint. In my case my problem is a little easier because the whole BaseX database is really a cache of what's in a separate git repo, so any time the git repo is updated (new commit or new branch creation or check out) I refresh the BaseX database and can regenerate my cache at that time, so it's not a big deal, just a mismatch between how I would do things in e.g., a Java application and how they have to be done using RESTXQ. I have looked at the DBA code but I was having a hard time understanding exactly what it was doing in the short time I had to work on it (although I did see what it was doing with db:output() and redirection). Cheers, Eliot ---- Eliot Kimber, Owner Contrext, LLC http://contrext.com On 7/13/15, 2:59 AM, "Dirk Kirsten" <basex-talk-boun...@mailman.uni-konstanz.de on behalf of d...@basex.org> wrote: >Hello Eliot, > >You can add the documents directly using the db:create() function, thus >being able to create and initialize the database. If you have multiple >documents to add it can be done like the following example: > > db:create('new-database', (<some-data/>, <more-data/>), >("somedata.xml", "moredata.xml")) > >Hope this helps, >Dirk > >On 07/11/2015 07:38 PM, Eliot Kimber wrote: >> In my link management application I'm trying to refactor my code to move >> my link management metadata out of the content database (the one that >> otherwise has the user's XML docs) and into a separate database. >> >> The problem I'm running into is that because db:create() is put last on >> the pending updates list, you can't do >> >> return ( >> db:create('new-database'), >> db:add('new-database', '<some-data/>')) >> >> There doesn't seem to be a direct way through the RESTXQ-managed >> application to create the database since updating functions don't return >> anything (so I can't, for example, have the root page handler ensure >>that >> the database is there simply by calling an XQuery function to initial >>it). >> >> I think the only solutions are: >> >> 1. Have the database creation managed outside the REST application >>(e.g., >> in my git hooks, which are where the content database creation is done) >> >> 2. Use the redirect technique so that, for example, the root page is >> handled by an updating function that does the database initialization >>and >> then returns a redirect to the real root page handler. >> >> Have I missed an option? >> >> Thanks, >> >> Eliot >> >> ---- >> Eliot Kimber, Owner >> Contrext, LLC >> http://contrext.com >> >> >> > >-- >Dirk Kirsten, BaseX GmbH, http://basexgmbh.de >|-- Firmensitz: Blarerstrasse 56, 78462 Konstanz >|-- Registergericht Freiburg, HRB: 708285, Geschäftsführer: >| Dr. Christian Grün, Dr. Alexander Holupirek, Michael Seiferle >`-- Phone: 0049 7531 28 28 676, Fax: 0049 7531 20 05 22 > >
