Re: [basex-talk] Simple query

-- Aaron On March 11, 2017 11:25:08 AM EST, "Christian Grün" christian.gruen@gmail.com wrote: >> I was going to open the local session and keep it open for the >lifetime of >> the webapp like I would do with a JDBC session object. That would not >allow >> me to use the autoclose. Is it possible or recommended to keep the >one >> session object like that? > >Absolutely. BaseX sessions are pretty light-weight, but if you want to >repeatedly access a database/collection (as you did), and avoid >reopening it every time, it can make sense to keep sessions open. > > > >> On March 11, 2017 11:07:31 AM EST, "Christian Grün" >> christian.gruen@gmail.com wrote: >>> >>> Dear Aaron (and thanks Kendall), >>> >>> A little addendum: If you use Java’s try-with-resources statement… >>> >>> try (LocalSession session = new LocalSession(this.context)) >>> >>> …there will be no need to manually close your connection. >>> >>> Best, >>> Christian >>> >>> >>> >>> On Fri, Mar 10, 2017 at 10:47 PM, AJ Weber aweber@comcast.net >wrote: >>>> >>>> OK, changing this so that the code flows like yours works much, >much >>>> better. >>>> I now return all 3 documents I expect are in the database. >>>> >>>> FOLLOW-UP Question: How do I close the database properly with >these >>>> classes? I had been doing a context.closeDB() when shutting-down. > Do I >>>> just 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 >I sent >>>> before) the database BEFORE creating a LocalSession and I am using >the >>>> new >>>> Check(...).execute(context); >>>> >>>> The "context" is kept in the object's class-level. >>>> >>>> Your code creates the context, associates the new LocalSession >with the >>>> context, and THEN opens the existing database. (That's more akin >to how >>>> a >>>> JDBC session would go...but I did not see any java examples with >this, I >>>> followed the examples on the java page and only found LocalSession >via a >>>> google search.) >>>> >>>> There doesn't appear to be any details in the javadoc or anything >I can >>>> find >>>> regarding how to use LocalSession, so I could be off base from >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 seems >like >>>> there are some details left out. >>>> >>>> >>>> >>>> Kendall >>>> >>>> >>>> >>>> From: basex-talk-bounces@mailman.uni-konstanz.de on behalf of AJ >Weber >>>> aweber@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 a >>>> database >>>> open and this does not throw an exception, it just returns no >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 with >>>> exclusively >>>> 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 specific >collection >>>> in >>>> the query. >>>> >>>> >>>> >>>> >>>> Kendall >>>> >>>> >>>> >>>> >>>> >>>> From: basex-talk-bounces@mailman.uni-konstanz.de on behalf of AJ >Weber >>>> aweber@comcast.net >>>> Date: Friday, March 10, 2017 at 6:44 AM >>>> To: Fabrice ETANCHAUD fetanchaud@groupefbo.com, >>>> "basex-talk@mailman.uni-konstanz.de" >>>> 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-bounces@mailman.uni-konstanz.de >>>> [mailto:basex-talk-bounces@mailman.uni-konstanz.de] De la part de >Aaron >>>> Weber >>>> Envoyé : jeudi 9 mars 2017 00:31 >>>> À : 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 >>> >>> >>> >>> >>> >>> >>> >>> >>> >>