Re: [basex-talk] Simple query

AJ Weber Fri, 10 Mar 2017 13:49:56 -0800

OK, changing this so that the code flows like yours works much, muchbetter. I now return all 3 documents I expect are in the database.

FOLLOW-UP Question: How do I close the database properly with theseclasses? I had been doing a context.closeDB() when shutting-down. Do Ijust do a localSession.close() now? Or do I need to do both?


Thanks again!!!



On 3/10/2017 4:27 PM, AJ Weber wrote:

Well, one difference I spot is that I am opening (via the snippet Isent before) the database BEFORE creating a LocalSession and I amusing the new Check(...).execute(context);


The "context" is kept in the object's class-level.

Your code creates the context, associates the new LocalSession withthe context, and THEN opens the existing database. (That's more akinto how a JDBC session would go...but I did not see any java exampleswith this, I followed the examples on the java page and only foundLocalSession via a google search.)

There doesn't appear to be any details in the javadoc or anything Ican find regarding how to use LocalSession, so I could be off basefrom that pov.


-AJ


On 3/10/2017 4:18 PM, Kendall Shaw wrote:


This worked for me, where “test-local” contains a document:

Context context = new Context();

LocalSession s = new LocalSession(context);

s.execute(new Check("test-local"));

        try (Query q = s.query("for $doc in collection() return $doc")) {

while (q.more()) {

  System.out.println(q.next()_);_

            }

        }

But, why your code isn’t working could be useful to know. It seemslike there are some details left out.


Kendall

*From: *<basex-talk-boun...@mailman.uni-konstanz.de> on behalf of AJWeber <awe...@comcast.net>

*Date: *Friday, March 10, 2017 at 11:40 AM

*To: *"basex-talk@mailman.uni-konstanz.de"<basex-talk@mailman.uni-konstanz.de>

*Subject: *Re: [basex-talk] Simple query

On 3/10/2017 2:24 PM, Kendall Shaw wrote:

    Michael Seiferle gave the answer already, I think. What would
    collection() be referring to? How would BaseX know what to
    return? Probably there is no database specified. Presumably, in
    the GUI you have opened a database.

Yes, I did not include my code to open the database. There is adatabase open and this does not throw an exception, it just returnsno results.


In my constructor of this class there is the following code:
new Check(this.MyID).execute(context);

(MyID is a String identifying the database I want to work withexclusively with this context passed.)

As I mentioned in a separate post, my query where matches(uri...)works fine...every time. That query also does not have a specificcollection in the query.



    Kendall

    *From: *<basex-talk-boun...@mailman.uni-konstanz.de>
    <mailto:basex-talk-boun...@mailman.uni-konstanz.de> on behalf of
    AJ Weber <awe...@comcast.net> <mailto:awe...@comcast.net>
    *Date: *Friday, March 10, 2017 at 6:44 AM
    *To: *Fabrice ETANCHAUD <fetanch...@groupefbo.com>
    <mailto:fetanch...@groupefbo.com>,
    "basex-talk@mailman.uni-konstanz.de"
    <mailto:basex-talk@mailman.uni-konstanz.de>
    <basex-talk@mailman.uni-konstanz.de>
    <mailto:basex-talk@mailman.uni-konstanz.de>
    *Subject: *Re: [basex-talk] Simple query

    On 3/9/2017 3:46 AM, Fabrice ETANCHAUD wrote:

        Hello Aaron,

        You would learn faster by using the BaseXGUI application,

        You will benefit from syntax highlighting, real time
        execution, and hits on function signatures.

    I am trying the GUI now.  It is an excellent tool!

    However, issuing the same exact XQuery in the GUI returns 3
    documents (which is what I would have originally expected).

    Maybe it is an issue with how I setup my query in java? Here is
    my code:

            try (LocalSession session = new LocalSession(this.context)) {
                //test

                try (Query q = session.query("for $doc in
    collection() return $doc")) {
                    while (q.more()) {
                        LOG.debug("RESULT: " + q.next());
                    }
                }
            }
            catch (Exception e) {
                LOG.error("Could not execute query " + statement, e);
            }



        Best regards,

        Fabrice

        *De :*basex-talk-boun...@mailman.uni-konstanz.de
        <mailto:basex-talk-boun...@mailman.uni-konstanz.de>
        [mailto:basex-talk-boun...@mailman.uni-konstanz.de] *De la
        part de* Aaron Weber
        *Envoyé :* jeudi 9 mars 2017 00:31
        *À :* basex-talk@mailman.uni-konstanz.de
        <mailto:basex-talk@mailman.uni-konstanz.de>
        *Objet :* [basex-talk] Simple query

        Newbie alert.

        I'm trying to get my feet wet with BaseX, and in doing so, am
        trying to understand XQuery and how to apply it to a database
        full of documents (not just a single document that is
        typically queried).

        I am using Java and can post my code, but with a
        LocalSession, and a query, the following produces 0 results.

        For $doc in collection() return $doc

        I realize there's no "where", and in the sql world that would
        match all. Maybe not in XQuery?

        Obviously just a test query, but I need to start somewhere. :-)

        Thanks for any help!

--AJ

Re: [basex-talk] Simple query

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