BaseX-Talk February 2011

basex-talk@mailman.uni-konstanz.de

26 participants
48 discussions

Out of memory bug
by Ivan Lagunov 31 Jul '13

31 Jul '13

Hello, I've got 'Out of memory' error and corrupted database again, this time it's for 6.3 version. Steps: 1. Started server, started terminal client, checked there are no text and attribute indexes. 2. Started my Java application that runs several tests on database: querying, adding, removing. 3. Then I forgot to reopen terminal client and used the one that I opened in Step 1. 4. Run optimize command for the collection and got error. 5. Cannot open the collection any more as I'm getting 'Out of memory'. It's clear that I shouldn't have used the terminal client that I opened before execution of my Java application. But sometimes it's hard to remember. And it's completely unacceptable that these actions result in the corrupted database. You really should catch ArrayIndexOutOfBoundsException everywhere in order to save database from being corrupted. Terminal client stacktrace: > optimize Possible bug? Feedback is welcome: basex-talk(a)mailman.uni-konstanz.de BaseX 6.3: java.lang.ArrayIndexOutOfBoundsException: -1 org.basex.data.PathSummary.add(PathSummary.java:68) org.basex.core.cmd.Optimize.stats(Optimize.java:68) org.basex.core.cmd.Optimize.run(Optimize.java:34) org.basex.core.Command.run(Command.java:236) org.basex.core.Command.exec(Command.java:218) org.basex.core.Command.execute(Command.java:66) org.basex.server.ServerProcess.run(ServerProcess.java:161) > open products Out of Main Memory. Best regards, Ivan

4 8

deadlock in BaseXServer 6.2.7
by Godmar Back 23 Jun '12

23 Jun '12

Hi, we're observing that our BaseXServer 6.2.7 deadlocks. The stack traces are here: http://top.cs.vt.edu/~gback/bx/deadlock-6.2.7/basex-deadlock.txt Could you take a look to see if these ring any bells? Has this problem been addressed in a more recent version? - Godmar

3 5

Problems in using BaseX REST server - IncompatibleClassChangeError javax.ws.rs.core.Response$Status does not implement the requested interface
by Pushkaraj Thorat 21 Oct '11

21 Oct '11

Hello, I am doing setup for REST enabled basex database with procedure mentioned in http://docs.basex.org/wiki/JAX-RX_API URL. Configuring & starting server and running failed due to class not found, but later I've modified the ./basexrest script as: (Included all the jars in lib folder) ######START #!/bin/bash # Path to this script PWD=`dirname $0` # Paths to distributed files or source directories BASEX=$PWD/BaseX.jar BASEXAPI=$PWD/../lib/basex-api.jar # Classpath LIB=$PWD/../lib LIB_CP="" for JAR_FILE in $LIB/*.jar do LIB_CP="$LIB/$JAR_FILE:$LIB_CP" done CP=$BASEX:$BASEXAPI:$LIB_CP # Options for virtual machine VM=-Xmx1g # Run REST server java -cp "$CP" $VM org.basex.api.jaxrx.JaxRxServer "$@" ######END after this, server started successfully, hit the URL - http://localhost:8984/basex/jax-rx I am getting following exception: java.lang.IncompatibleClassChangeError: Class javax.ws.rs.core.Response$Status does not implement the requested interface javax.ws.rs.core.Response$StatusType at com.sun.jersey.spi.container.ContainerResponse.getStatus(ContainerResponse.java:548) at com.sun.jersey.spi.container.ContainerResponse$CommittingOutputStream.commitWrite(ContainerResponse.java:156) at com.sun.jersey.spi.container.ContainerResponse$CommittingOutputStream.write(ContainerResponse.java:133) at org.basex.io.BufferedOutput.flush(BufferedOutput.java:50) at org.basex.io.PrintOutput.flush(PrintOutput.java:126) at org.basex.data.XMLSerializer.cls(XMLSerializer.java:206) at org.basex.data.Serializer.close(Serializer.java:219) at org.basex.api.jaxrx.BXJaxRx$1.code(BXJaxRx.java:96) at org.basex.api.jaxrx.BXCode.run(BXCode.java:53) at org.basex.api.jaxrx.BXOutput.write(BXOutput.java:53) at com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider.writeTo(StreamingOutputProvider.java:71) at com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider.writeTo(StreamingOutputProvider.java:57) at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:299) Your help is appreciated. Thanks, Pushkaraj

3 6

Problem with Wikipedia database (or a more general namespace efficiency problem?)
by NewIntellectual 01 Mar '11

01 Mar '11

As both a stress test and to experiment, I created a database using a recent complete (current page) dump of English Wikipedia, a hefty file of 30.5 GB. I don't have enough memory apparently to create a full-text index of all of that text, so I created the DB without one. My first testing came up empty until I realized that I needed to deal with the namespace (ugh). Then I tried: declare default element namespace "http://www.mediawiki.org/xml/export-0.4/ "; //siteinfo This contains a small amount of data and occurs only once in the document (at /mediawiki/siteinfo). However, it's extremely slow (~33 seconds on my system). The query plan is: <IterPath> <Root/> <IterStep axis="child" test="*:mediawiki"/> <IterStep axis="child" test="*:siteinfo"/> </IterPath> Timing: - Parsing: 0.35 ms - Compiling: 0.22 ms - Evaluating: 33316.32 ms - Printing: 0.3 ms - Total Time: 33317.19 ms My surmise is that millions of node names are being checked rather than a path index being used to rapidly access the appropriate node(s). I don't think such a simple query should fail to be properly optimized. Another surmise is that it's related to namespaces not being indexed (?). While personally I very much dislike namespaces, they are common, and they have to be efficiently handled. To see if it made a difference, I also tried an explicitly named namespace test: declare namespace w="http://www.mediawiki.org/xml/export-0.4/"; //w:siteinfo This results in: <IterPath> <Root/> <IterStep axis="descendant" test="w:siteinfo"/> </IterPath> Timing: - Parsing: 0.33 ms - Compiling: 0.07 ms - Evaluating: 54288.51 ms - Printing: 0.3 ms - Total Time: 54289.23 ms So performance is even worse.

4 11

FindBugs for BaseX
by Godmar Back 26 Feb '11

26 Feb '11

2011/2/26 Leonard Wörteler <leonard.woerteler(a)uni-konstanz.de>: > Hi Godmar, > > that bug was pretty easy to fix, and I have no idea how the superfluous > downcast passed all our tests. It was introduced in version 6.2.8. Generally, downcasts are bad software engineering practice and can and should be avoided or minimized by proper design. Either change the method signature to let the compiler flag attends at passing incompatible types, or add virtual methods to a superclass/interface, or (last resort) use instanceof. Findbugs is a tool that flags errors such as these; you may have heard of it. Running Findbugs over the current codebase yields 563 warnings, some of which are clear bugs. I recommend you do that. For example: void delete(final int pre, final int size) { NSNode nd = root.find(pre); if(nd.pre == pre) nd = nd.par; if(nd == null) root = rootDummy; while(!nd.equals(rootDummy)) { nd.delete(pre, size); nd = nd.par; } } if 'nd == null', 'nd.equals()' crashes. If it can't be null, then 'root = rootDummy' is bogus. Or: case GRANT: final CmdPerm perm = consume(CmdPerm.class, cmd); if(perm == null) help(null, cmd); final String db = key(ON, null) ? name(cmd) : null; key(TO, cmd); return db == null ? new Grant(perm, name(cmd)) : new Grant(perm, name(cmd), db); if 'perm' is null, you crash in the 'Grant' constructor when calling perm.toString(). If it can't be null, the check is bogus. Or: @Override public boolean uses(final Use u) { return u == Use.CTX && (def == FunDef.MB || def == FunDef.MB || def == FunDef.EVAL || def == FunDef.RUN) || super.uses(u); } Did you mean to check for two different values instead of FunDef.MB twice. Or: // [CG] XQuery/Formatter: calendars and places are ignored if(cal != null || plc != null); Did you mean to return if cal != null || plc != null rather than doing nothing? Or in FTWrods.java if(iat == null) { final FTLexer lex = new FTLexer(ftt.opt); /* elided */ if(iat == null) { iat = ia; tl = t; } else if(mode == FTMode.M_ALL || mode == FTMode.M_ALLWORDS) { iat = FTIndexIterator.intersect(ia, iat, 0); tl += t; } else { iat = FTIndexIterator.union(ia, iat); tl = Math.max(t, tl); } iat.tokenNum(++ctx.ftoknum); } return iat.more() ? new FTNode(iat.matches(), data, iat.next(), tl, iat.indexSize(), iat.score()) : null; } The code in the else branch is dead - iat is always null where you test it due to the dominating test on entry. The 'intersect' and 'union' call is never made. Etc. well worth the time fixing. - Godmar

2 1

Options to generate JSON file
by Jan Vlčinský (CAD) 26 Feb '11

26 Feb '11

Hi I shall export JSON file based on XML structures I have in my XQuery. Here I found http://demo.exist-db.org/xquery/json-test.xql/source sample, how eXistDB can produce JSON data. It is like import module namespace json="http://www.json.org"; 04. 05.declare option exist:serialize "method=xhtml media-type=text/html"; let $xml1 := 08.<root> 09.<h1>H</h1> 10.<p/> 11.<p>some text</p> 12.<h2>HH</h2> 13.</root> <script type="text/javascript"> 43.var data1 = {json:xml-to-json($xml1)}; BaseX does not provide this and I wonder, what options I have and what would anyone recommend 1. building up plain text piece by piece by XQuery 2. using some Java lib for this (there are more, any practical experience welcome) 3. Some other trick, which lives hidden to me (I already queried BaseX wiki and no hit) Jan -- *Ing. Jan Vlčinský* CAD programy Slunečnicová 338/3, 734 01 Karviná Ráj, Czech Republic tel: +420-597 602 024; mob: +420-608 979 040 skype: janvlcinsky; GoogleTalk: jan.vlcinsky(a)gmail.com http://cz.linkedin.com/in/vlcinsky

3 3

Server Crash
by Sony Vijay 26 Feb '11

26 Feb '11

Hi, I am using BaseX 6.5. I am running into a server crash. Could you fix it ? I see the following error where I run my server: Exception in thread "Thread-4" java.lang.NullPointerException at org.basex.query.up.Updates.size(Updates.java:110) at org.basex.query.QueryProcessor.updates(QueryProcessor.java:234) at org.basex.server.QueryProcess.initInfo(QueryProcess.java:162) at org.basex.server.QueryProcess.close(QueryProcess.java:139) at org.basex.server.ServerProcess.query(ServerProcess.java:291) at org.basex.server.ServerProcess.run(ServerProcess.java:128) Also, please find attached a copy of the complete log file. Thanks, Sony

5 7

Re: [basex-talk] BaseX question - Enhancing JAX-RX interface
by Jan Vlčinský (CAD) 26 Feb '11

26 Feb '11

Hi Christian I did try to write my ideas, but landed at reading what is REST and what not - and run out of time. So here is draft of some of ideas - unfortunately without clear proposal for next action, but someone will probably take it over and move on. Jan JAX-RX and BaseX - Aim - Summarize ideas and requests regarding JAX-RX interface of BaseX database - Topics - Mixing commands and queries in one request - Get and relevant post implementation without breaking compatibility - Are we REST like and do we need it? - What processing context we need - Typical Use Cases - Add document(s) and optimize - why - Want to be sure, that indexes will be updated after collection has been modified and no one will have a chance to run a query on not optimized collection - Updating query and optimize - why - Want to be sure, that indexes will be updated after collection has been modified and no one will have a chance to run a query on not optimized collection - Query with client defined timeout - why - It is better to quit too long query then risking that one too expensive query would endanger overall server performance There is no need to get query results too late, when our http connection already timed out - Set of independent simple expression queries - Mix updating and simple expression queries - Set of independent commands - why - Needing to run a batch of tasks, which cannot be interrupted by other clients - Ideas - add timeout parameter to each request - check, what other timeout-like parameters we may need - introduce new request element for POST, mixing queries and commands - Possible problems - compatibility with existing design - wish to pass query result into next command/query 2011/2/24 Christian Grün <christian.gruen(a)gmail.com> > > OK, I understand, that REST allows to perform the (SET) command, but to > use > > it with a query, I have to send the query in another, following, request. > > Will this second request keep enough context at the server side to know, > it > > shall use that timeout? > > Just recently, I've thought about extending the JAX-RX Interface to > allow more than a single query or command, or to allow both commands > and queries; regarding the syntax, this could be easily realized for > the GET method: > > http://localhost:8984/basex/jax-rx/factbook?query=1&query=2 > > http://localhost:8984/basex/jax-rx/factbook?command=set+timeout+1&query=1&c… > > On the other hand, I haven't decided yet how to best realize it for > the POST method without giving up compatibility. One solution could be > to introduce alternative "request" root elements: > > <request xmlns="http://jax-rx.sourceforge.net"> > <command> > <text>set timeout 1</text> > </command> > <query> > <text>//name</text> > <parameter name="count" value="5"/> > </query> > </request> > > What does everyone think? > Christian > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk(a)mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > -- *Ing. Jan Vlčinský* CAD programy Slunečnicová 338/3, 734 01 Karviná Ráj, Czech Republic tel: +420-597 602 024; mob: +420-608 979 040 skype: janvlcinsky; GoogleTalk: jan.vlcinsky(a)gmail.com http://cz.linkedin.com/in/vlcinsky

2 6

Re: [basex-talk] Mixing non-updating and updating expressions in a single query
by Sony Vijay 25 Feb '11

25 Feb '11

@Christian and Lukas: Many thanks for helping me with the transform expression so far. However, I am not sure if we can use both non-updating and updating expressions in a single query ? Meaning, I am trying to modify one document and insert the modified document into the second document. *Example:* let $newchild := "This is a child node" copy $c := <entry><title>How to use updating and non-updating expressions together</title> <child>child 1<child> <child>child 2</child> </entry> modify ( for $child in $c//child return replace value of node $child with $newchild ) return insert node $c into doc('seconddocument') I also tried: let $newchild := "This is a child node" copy $c := <entry><title>How to use updating and non-updating expressions together</title> <child>child 1<child> <child>child 2</child> </entry> return modify ( for $child in $c//child return replace value of node $child with $newchild ) insert node $c into doc('seconddocument') Of course, I can achieve this when I use two xqueries (one to return the modified document and the other to insert it into a second document). But, it would be great if I could perform both actions in a single query. Thanks, Sony On Fri, Feb 25, 2011 at 2:54 AM, Christian Grün <christian.gruen(a)gmail.com>wrote: > > I'm sure the somewhat unrelated syntax error message didn't > > help you to find this ... sorry for that. > > I agree with Lukas. I've revised the misleading error feedback; feel > free to check out the latest build: > > http://files.basex.org/releases/latest/ > > C. > ___________________________ > > On Fri, Feb 25, 2011 at 7:46 AM, Lukas Kircher > <lukaskircher1(a)googlemail.com> wrote: > > Hey Sony, > > > > I found another small typo in your query - the keyword 'node' > > is missing in your replace statement. So if you execute the > > query below you should be fine. > > > > for $childentry in $c//childentry > > return replace value of node $childentry/@id with > > concat('New Child: ', data($c//childentry/@id)) > > > > Regards, > > Lukas > > > > > > > > On Thu, Feb 24, 2011 at 11:08 PM, Sony Vijay <sony.vibh(a)gmail.com> > wrote: > >> > >> .. I see the syntax error : > >> [XPST0003] Expecting ")", found "v". > >> when I try : > >> > >> for $childentry in $c//childentry > >> return replace value of $childentry/@id with > >> concat('New Child: ', data($c//childentry/@id)) > >> > >> To modify the child entries like so: > >> <childentry id="1"> ----- > <childentry id="New Child: 1"> > >> > >> On Thu, Feb 24, 2011 at 5:03 PM, Sony Vijay <sony.vibh(a)gmail.com> > wrote: > >>> > >>> ... Replacing the values of attribute nodes doesn't seem to work as > >>> expected when I use modify. Please see my previous post with correction > in > >>> the typo. > >>> > >>> On Thu, Feb 24, 2011 at 5:00 PM, Sony Vijay <sony.vibh(a)gmail.com> > wrote: > >>>> > >>>> Please ignore the typo. My sample xquery looks something like this: > >>>> > >>>> for $childentry in $c//childentry > >>>> return replace value of $childentry/@id with > >>>> concat('New Child: ', data($c//childentry/@id)) > >>>> > >>>> To modify the child entries like so: > >>>> <childentry id="1"> ----- > <childentry id="New Child: 1"> > >>>> > >>>> > >>>> On Thu, Feb 24, 2011 at 4:50 PM, Sony Vijay <sony.vibh(a)gmail.com> > wrote: > >>>>> > >>>>> Christian, > >>>>> Yes. I did realize that I must use a RETURN statement. I tried that > >>>>> with a slight change in the requirement. Say, my child entries look > like so > >>>>> : > >>>>> > >>>>> <childentry id="1" /> > >>>>> I tried: > >>>>> for $childentry in $c//childentry > >>>>> return replace value of $childentry/@id with > >>>>> concat('New Child: ', $c//childentry/text()) > >>>>> Does replace work differently for attributes ? > >>>>> Thanks, > >>>>> Sony > >>>>> > >>>>> > >>>>> On Thu, Feb 24, 2011 at 3:27 PM, Christian Grün > >>>>> <christian.gruen(a)gmail.com> wrote: > >>>>>> > >>>>>> Sony, > >>>>>> > >>>>>> each FLWOR expression needs to be completed with a RETURN statement. > >>>>>> Please insert the following snippet (haven't tried it live): > >>>>>> > >>>>>> for $childentry in $c//childentry > >>>>>> return replace value of $childentry with > >>>>>> concat('New Child: ', $c//childentry/text()) > >>>>>> > >>>>>> Hope this helps, > >>>>>> Christian > >>>>>> ___________________________ > >>>>>> > >>>>>> Christian Grün > >>>>>> Uni KN, Box 188 > >>>>>> 78457 Konstanz, Germany > >>>>>> http://www.inf.uni-konstanz.de/~gruen > >>>>>> > >>>>>> > >>>>>> > >>>>>> On Thu, Feb 24, 2011 at 9:24 PM, Sony Vijay <sony.vibh(a)gmail.com> > >>>>>> wrote: > >>>>>> > Christian, > >>>>>> > Thank you very much for helping me with the query. However, I am > not > >>>>>> > quite > >>>>>> > sure how the transform operation works if I have to use a for > loop. > >>>>>> > Say, I > >>>>>> > twist around yesterday's question a bit like so: > >>>>>> > copy $c := > >>>>>> > <entry> > >>>>>> > <id>1</id> > >>>>>> > <title>How to use a transform expression</title> > >>>>>> > <updated>2011-02-23</updated> > >>>>>> > <author> > >>>>>> > <name>BaseX Team</name> > >>>>>> > <uri>http://basex.org</uri> > >>>>>> > </author> > >>>>>> > <childentry> 1 </childentry> > >>>>>> > <childentry> 2 </childentry> > >>>>>> > <childentry> 3 </childentry> > >>>>>> > <content type="html">Transform expression example created by > BaseX > >>>>>> > Team</content> > >>>>>> > </entry> > >>>>>> > modify ( > >>>>>> > replace value of node $c//name with 'BaseX', > >>>>>> > replace value of node $c//content with concat('Copy of: ', > >>>>>> > $c//content), > >>>>>> > insert node <member>Joey</member> into $c//author > >>>>>> > for $childentry in $c//childentry > >>>>>> > replace value of $childentry with concat('New Child: ', > >>>>>> > $c//childentry/text()) > >>>>>> > ) > >>>>>> > return $c > >>>>>> > > >>>>>> > The expected output is: > >>>>>> > <entry> > >>>>>> > <id>1</id> > >>>>>> > <title>How to use a transform expression</title> > >>>>>> > <updated>2011-02-23</updated> > >>>>>> > <author> > >>>>>> > <name>BaseX</name> > >>>>>> > <uri>http://basex.org</uri> > >>>>>> > <member>Joey</member> > >>>>>> > </author> > >>>>>> > <childentry> New Child: 1 </childentry> > >>>>>> > <childentry> New Child: 2 </childentry> > >>>>>> > <childentry> New Child: 3 </childentry> > >>>>>> > <content type="html">Copy of: Transform expression example > created > >>>>>> > by > >>>>>> > BaseX Team</content> > >>>>>> > </entry> > >>>>>> > The following exception is thrown when I tried my sample > >>>>>> > transformation > >>>>>> > query with the for loop: > >>>>>> > [XPST0003] Expecting 'where', 'order' or 'return' expression. > >>>>>> > Thanks, > >>>>>> > Sony > >>>>>> > PS: @Lukas: I did notice the update in the documentation. Thank > you > >>>>>> > ! > >>>>>> > > >>>>>> > > >>>>>> > On Wed, Feb 23, 2011 at 2:32 AM, Lukas Kircher > >>>>>> > <lukaskircher1(a)googlemail.com> wrote: > >>>>>> >> > >>>>>> >> Hi Sony, > >>>>>> >> > >>>>>> >> to help others with the same question, I allowed myself to > >>>>>> >> add a modified version of your example to our > >>>>>> >> documentation [1]. > >>>>>> >> > >>>>>> >> Regards, > >>>>>> >> Lukas > >>>>>> >> > >>>>>> >> > >>>>>> >> [1] http://docs.basex.org/wiki/Update#transform > >>>>>> >> > >>>>>> >> > >>>>>> >> > >>>>>> >> On Wed, Feb 23, 2011 at 6:58 AM, Sony Vijay <sony.vibh(a)gmail.com > > > >>>>>> >> wrote: > >>>>>> >>> > >>>>>> >>> Christian, > >>>>>> >>> Thank you for the quick and helpful reply. > >>>>>> >>> - Sony > >>>>>> >>> > >>>>>> >>> On Tue, Feb 22, 2011 at 5:56 PM, Christian Grün > >>>>>> >>> <christian.gruen(a)gmail.com> wrote: > >>>>>> >>>> > >>>>>> >>>> Sony, > >>>>>> >>>> > >>>>>> >>>> the following query might do what you want: > >>>>>> >>>> > >>>>>> >>>> copy $c := > >>>>>> >>>> <entry xmlns="http://www.w3.org/2005/Atom" > >>>>>> >>>> xmlns:libx="http://libx.org/xml/libx2"> > >>>>>> >>>> <id>1</id> > >>>>>> >>>> <title>Link Amazon By ISBN</title> > >>>>>> >>>> <updated>2010-09-29T18:37:48.592Z</updated> > >>>>>> >>>> <author> > >>>>>> >>>> <name>LibX Team</name> > >>>>>> >>>> <uri>http://libx.org</uri> > >>>>>> >>>> <email>libx.org(a)gmail.com</email> > >>>>>> >>>> </author> > >>>>>> >>>> <content type="html">Content created by LibX Libapp > >>>>>> >>>> Builder</content> > >>>>>> >>>> </entry> > >>>>>> >>>> modify ( > >>>>>> >>>> replace value of node $c//*:name with 'Sony', > >>>>>> >>>> replace value of node $c//*:content with > >>>>>> >>>> concat('Copy of: ', $c//*:content) > >>>>>> >>>> ) > >>>>>> >>>> return $c > >>>>>> >>>> > >>>>>> >>>> > >>>>>> >>>> Best, > >>>>>> >>>> Christian > >>>>>> >>>> ___________________________ > >>>>>> >>>> > >>>>>> >>>> On Tue, Feb 22, 2011 at 11:43 PM, Sony Vijay > >>>>>> >>>> <sony.vibh(a)gmail.com> > >>>>>> >>>> wrote: > >>>>>> >>>> > Hi, > >>>>>> >>>> > I am using BaseX 6.5. I am trying to transform a given node > >>>>>> >>>> > using an > >>>>>> >>>> > XQuery. > >>>>>> >>>> > > >>>>>> >>>> > Say, I have an node like so: > >>>>>> >>>> > <entry xmlns="http://www.w3.org/2005/Atom" > >>>>>> >>>> > xmlns:libx="http://libx.org/xml/libx2"> > >>>>>> >>>> > <id>1</id> > >>>>>> >>>> > <title>Link Amazon By ISBN</title> > >>>>>> >>>> > <updated>2010-09-29T18:37:48.592Z</updated> > >>>>>> >>>> > <author> > >>>>>> >>>> > <name>LibX Team</name> > >>>>>> >>>> > <uri>http://libx.org</uri> > >>>>>> >>>> > <email>libx.org(a)gmail.com</email> > >>>>>> >>>> > </author> > >>>>>> >>>> > <content type="html">Content created by LibX Libapp > >>>>>> >>>> > Builder</content> > >>>>>> >>>> > </entry> > >>>>>> >>>> > I am trying to send this node to an xquery which is expected > to > >>>>>> >>>> > do the > >>>>>> >>>> > following actions: > >>>>>> >>>> > > >>>>>> >>>> > create a copy of this node (so that the actual node in the > >>>>>> >>>> > database > >>>>>> >>>> > does not > >>>>>> >>>> > change), > >>>>>> >>>> > transform/modify the duplicate copy of the given node > >>>>>> >>>> > return the modified duplicate copy of the given node > >>>>>> >>>> > > >>>>>> >>>> > I would expect the output to be like so: > >>>>>> >>>> > <entry xmlns="http://www.w3.org/2005/Atom" > >>>>>> >>>> > xmlns:libx="http://libx.org/xml/libx2"> > >>>>>> >>>> > <id>1</id> > >>>>>> >>>> > <title>Link Amazon By ISBN</title> > >>>>>> >>>> > <updated>2010-09-29T18:37:48.592Z</updated> > >>>>>> >>>> > <author> > >>>>>> >>>> > <name>Sony</name> > >>>>>> >>>> > <uri>http://libx.org</uri> > >>>>>> >>>> > <email>libx.org(a)gmail.com</email> > >>>>>> >>>> > </author> > >>>>>> >>>> > <content type="html">Copy of: Content created by LibX > Libapp > >>>>>> >>>> > Builder</content> > >>>>>> >>>> > </entry> > >>>>>> >>>> > I tried to perform the non-updating functions using transform > >>>>>> >>>> > and also > >>>>>> >>>> > tried > >>>>>> >>>> > to use a pending update list > >>>>>> >>>> > (Reference: http://docs.basex.org/wiki/Update#transform). > None > >>>>>> >>>> > of this > >>>>>> >>>> > works > >>>>>> >>>> > as expected. Could you refer me to a more detailed > >>>>>> >>>> > documentation for > >>>>>> >>>> > performing such transform operations on nodes ? > >>>>>> >>>> > Thanks, > >>>>>> >>>> > Sony > >>>>>> >>>> > > >>>>>> >>>> > _______________________________________________ > >>>>>> >>>> > BaseX-Talk mailing list > >>>>>> >>>> > BaseX-Talk(a)mailman.uni-konstanz.de > >>>>>> >>>> > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > >>>>>> >>>> > > >>>>>> >>>> > > >>>>>> >>> > >>>>>> >>> > >>>>>> >>> _______________________________________________ > >>>>>> >>> BaseX-Talk mailing list > >>>>>> >>> BaseX-Talk(a)mailman.uni-konstanz.de > >>>>>> >>> https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > >>>>>> >>> > >>>>>> >> > >>>>>> > > >>>>>> > > >>>>> > >>>> > >>> > >> > > > > >

2 2

Re: [basex-talk] Use of For loop in transforming a node without changing the database
by Sony Vijay 25 Feb '11

25 Feb '11

Christian, Thank you very much for helping me with the query. However, I am not quite sure how the transform operation works if I have to use a for loop. Say, I twist around yesterday's question a bit like so: copy $c := <entry> <id>1</id> <title>How to use a transform expression</title> <updated>2011-02-23</updated> <author> <name>BaseX Team</name> <uri>http://basex.org</uri> </author> <childentry> 1 </childentry> <childentry> 2 </childentry> <childentry> 3 </childentry> <content type="html">Transform expression example created by BaseX Team</ content> </entry> modify ( replace value of node $c//name with 'BaseX', replace value of node $c//content with concat('Copy of: ', $c//content), insert node <member>Joey</member> into $c//author for $childentry in $c//childentry replace value of $childentry with concat('New Child: ', $c//childentry/text()) ) return $c *The expected output is:* <entry> <id>1</id> <title>How to use a transform expression</title> <updated>2011-02-23</updated> <author> <name>BaseX</name> <uri>http://basex.org</uri> <member>Joey</member> </author> <childentry> *New Child: 1* </childentry> <childentry> *New Child: 2 *</childentry> <childentry> *New Child: 3* </childentry> <content type="html">Copy of: Transform expression example created by BaseX Team</content> </entry> The following exception is thrown when I tried my sample transformation query with the for loop: *[XPST0003] Expecting 'where', 'order' or 'return' expression.* Thanks, Sony *PS: @Lukas: I did notice the update in the documentation. Thank you !* On Wed, Feb 23, 2011 at 2:32 AM, Lukas Kircher <lukaskircher1(a)googlemail.com > wrote: > Hi Sony, > > to help others with the same question, I allowed myself to > add a modified version of your example to our > documentation [1]. > > Regards, > Lukas > > > [1] http://docs.basex.org/wiki/Update#transform > > > > > On Wed, Feb 23, 2011 at 6:58 AM, Sony Vijay <sony.vibh(a)gmail.com> wrote: > >> Christian, >> >> Thank you for the quick and helpful reply. >> >> - Sony >> >> >> On Tue, Feb 22, 2011 at 5:56 PM, Christian Grün < >> christian.gruen(a)gmail.com> wrote: >> >>> Sony, >>> >>> the following query might do what you want: >>> >>> copy $c := >>> <entry xmlns="http://www.w3.org/2005/Atom" >>> xmlns:libx="http://libx.org/xml/libx2"> >>> <id>1</id> >>> <title>Link Amazon By ISBN</title> >>> <updated>2010-09-29T18:37:48.592Z</updated> >>> <author> >>> <name>LibX Team</name> >>> <uri>http://libx.org</uri> >>> <email>libx.org(a)gmail.com</email> >>> </author> >>> <content type="html">Content created by LibX Libapp Builder</content> >>> </entry> >>> modify ( >>> replace value of node $c//*:name with 'Sony', >>> replace value of node $c//*:content with >>> concat('Copy of: ', $c//*:content) >>> ) >>> return $c >>> >>> >>> Best, >>> Christian >>> ___________________________ >>> >>> On Tue, Feb 22, 2011 at 11:43 PM, Sony Vijay <sony.vibh(a)gmail.com> >>> wrote: >>> > Hi, >>> > I am using BaseX 6.5. I am trying to transform a given node using an >>> > XQuery. >>> > >>> > Say, I have an node like so: >>> > <entry xmlns="http://www.w3.org/2005/Atom" >>> > xmlns:libx="http://libx.org/xml/libx2"> >>> > <id>1</id> >>> > <title>Link Amazon By ISBN</title> >>> > <updated>2010-09-29T18:37:48.592Z</updated> >>> > <author> >>> > <name>LibX Team</name> >>> > <uri>http://libx.org</uri> >>> > <email>libx.org(a)gmail.com</email> >>> > </author> >>> > <content type="html">Content created by LibX Libapp Builder</content> >>> > </entry> >>> > I am trying to send this node to an xquery which is expected to do the >>> > following actions: >>> > >>> > create a copy of this node (so that the actual node in the database >>> does not >>> > change), >>> > transform/modify the duplicate copy of the given node >>> > return the modified duplicate copy of the given node >>> > >>> > I would expect the output to be like so: >>> > <entry xmlns="http://www.w3.org/2005/Atom" >>> > xmlns:libx="http://libx.org/xml/libx2"> >>> > <id>1</id> >>> > <title>Link Amazon By ISBN</title> >>> > <updated>2010-09-29T18:37:48.592Z</updated> >>> > <author> >>> > <name>Sony</name> >>> > <uri>http://libx.org</uri> >>> > <email>libx.org(a)gmail.com</email> >>> > </author> >>> > <content type="html">Copy of: Content created by LibX Libapp >>> > Builder</content> >>> > </entry> >>> > I tried to perform the non-updating functions using transform and also >>> tried >>> > to use a pending update list >>> > (Reference: http://docs.basex.org/wiki/Update#transform). None of this >>> works >>> > as expected. Could you refer me to a more detailed documentation for >>> > performing such transform operations on nodes ? >>> > Thanks, >>> > Sony >>> > >>> > _______________________________________________ >>> > BaseX-Talk mailing list >>> > BaseX-Talk(a)mailman.uni-konstanz.de >>> > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk >>> > >>> > >>> >> >> >> _______________________________________________ >> BaseX-Talk mailing list >> BaseX-Talk(a)mailman.uni-konstanz.de >> https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk >> >> >

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BaseX-Talk February 2011