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Re: [basex-talk] Strange query output
by Christian Grün 06 May '10

06 May '10

Thanks Toon, it's always interesting to hear about bugs that should have been encountered much earlier. This one might need some more time to be fixed, that's why I've added a sourceforge bug entry: https://sourceforge.net/tracker/?func=detail&aid=2997544&group_id=192179&at… Your query can be broken down to the following one: //a[b = //b] The general problem is that we attach text() location steps to a path if we know that the correspondent node is a leaf node. This way, we can rewrite queries to use the index more easily. I.e., the upper query is rewritten to: //a[b/text() = //b/text()] As the b elements are leaves in your example, but never have text() children, the predicate yields false… //a[ () = () ] In fact, for the given document, your test (b = //b) will result in an empty string test "" = "". This might be why no one else has stumbled over this before. The query info view in BaseX gives you some hint how queries are evaluated (…maybe you're using it anyway). Thanks, Christian PS: I've posted this to the mailing list to let others know as well. On Thu, May 6, 2010 at 11:05 AM, Calders, T.G.K. <t.calders(a)tue.nl> wrote: > Dear Christian, > > Sorry to bug you again. As you can guess, my lecture is on Thursday morning. > > The following query still gives an incorrect output in basex 6.1.1: > ----- > for $b in //b, $a in //a > where $a/b=$b > return <binding> > {$b} > {$a} > </binding> > ----- > When applied on the following document: > ----- > <doc> > <a id="1"> > <b id="1"/> > <c>1a</c> > <c>1b</c> > </a> > <a id="2"> > <b id="2"/> > <c>2a</c> > <c>2b</c> > </a> > </doc> > ----- > It returns an empty answer, whereas the correct answer creates 4 "binding"-elements (the where clause does not filter anything away as both "b"-elements in the document evaluate to "" under string()). > > On the other hand, > ----- > let $x:=<doc> > <a id="1"> > <b id="1"/> > <c>1a</c> > <c>1b</c> > </a> > <a id="2"> > <b id="2"/> > <c>2a</c> > <c>2b</c> > </a> > </doc> > > > for $b in $x//b, $a in $x//a > where $a/b=$b > return <binding> > {$b} > {$a} > </binding> > ----- > Does produce the correct output. I noticed that this error is present in some earlier versions of basex as well (e.g., in version 5.7 which I used last year). The query was evaluated correctly, though, in versions 4.0 and 5.0. > > Best regards, > Toon > > > -----Original Message----- > From: Christian Grün [mailto:christian.gruen@gmail.com] > Sent: donderdag 29 april 2010 16:51 > To: Calders, T.G.K. > Cc: basex-talk(a)mailman.uni-konstanz.de > Subject: Re: Strange query output > > Dear Toon Calders, > > thanks for your detailed bug report. Yes, this was a serious issue; > the predicate was optimized for an accessing the index, although it > was dependent on the query context. This is now fixed in the > repository version 6.1.1 of BaseX: > > http://basex.org/maven/org/basex/basex/6.1.1/ > > I've forwarded your mail to the mailing list to let others know about > it as well. > > All the best, > Christian > > > > On Thu, Apr 29, 2010 at 12:17 PM, Calders, T.G.K. <t.calders(a)tue.nl> wrote: >> Dear BaseX developers, >> >> First of all, many thanks for making this nice tool freely available. I use >> it in my Database class so the students can practice a bit with XPath and >> XQuery and they are all, without any exception, very enthusiastic about the >> tool. >> >> During class today, however, one of the students encountered a strange query >> output; I reduced the example to its essence: >> >> For the following document: >> >> <errordoc> >> <instructor fname="Toon" sname="Calders"/> >> <lecturer fname="Toon" sname="Calders"/> >> </errordoc> >> >> We ran the query "//instructor[@sname=../lecturer/@sname]" which returned >> an empty answer when executed with BaseX 6.1. (with previous versions it >> seems to work fine; e.g., 5.7). >> >> On the other hand, the query: >> >> let $x:=<errordoc> >> <instructor fname="Toon" sname="Calders"/> >> <lecturer fname="Toon" sname="Calders"/> >> </errordoc> >> >> return $x//instructor[@sname=../lecturer/@sname] >> >> does return: >> <instructor fname="Toon" sname="Calders"/> >> >> Best regards, >> Toon Calders >> TU Eindhoven ___________________________ Christian Gruen Universitaet Konstanz Department of Computer & Information Science D-78457 Konstanz, Germany Tel: +49 (0)7531/88-4449, Fax: +49 (0)7531/88-3577 http://www.inf.uni-konstanz.de/~gruen

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XPath function and same node name
by Grégoire Colbert 03 May '10

03 May '10

Hi, I have a long XML document like this : <cities> <city> <name>Paris</name> <zip>75000</zip> <alt_names> <name>paris</name> </alt_names> </city> <city> <name>Cesson-Sévigné</name> <zip>35510</zip> <alt_names> <name>paris</name> </alt_names> </city> </cities> My XQuery is supposed to return the cities whose name begin with a few letters contained in "$cityname". So I use this : let $search := request:get-parameter("search","") return <cities> { for $city in collection("cities")//city[starts-with(alt_names/name,$search)] return <city> {$city/name} {$city/zip} </city> } </cities> But there is a problem with the [starts-with(alt_names/name,$search)] part. It seems that I cannot use the same tag name ("name") both in "city" and in "alt_names". The error is : [XPTY0004] No sequence (element name { ... }, element name { ... }) allowed. 1) Is this a bug? 2) What is the equivalent in BaseX to request:get-parameter, which works in "eXist db" and affects the GET parameter (here "search") to the $search variable? Thank you for your help, Regards, Grégoire

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Fwd: Strange query output
by Christian Grün 29 Apr '10

29 Apr '10

Philip, as long as you don't work with our "api" and "example" packages, you don't need Maven at all. Talking about myself… I'm only using the Maven plugin to dissolve dependencies. I've posted this to the list, so maybe someone else can help you with that? Christian On Thu, Apr 29, 2010 at 5:40 PM, Philip Oliver <phil3(a)olivercomputing.com> wrote: > Christian - I was trying to update my Eclipse installation (Galileo SR2 on OS X) with the maven integration and it blew up my Eclipse installation. Not a BaseX problem but still annoying. I don't know much about Maven but I think I'd prefer to just build from the command line if possible using 'mvn' which is what I was doing with the 'mvn install'. Can you say what I should do in order to use 'mvn' at the command line (rather than Eclipse) to build BaseX to get a jar? > > Phil > > On Apr 29, 2010, at 11:37 AM, Christian Grün wrote: > >> Philip, >> >> thanks for the hint, it was work in progress. All JUnit tests should >> now run as expected. If not, just tell us (we note that many people >> have difficulties with the Eclipse/Maven integration, so I'm not sure >> if the current configuration meets all demands). >> >> Christian >> >> >> >> On Thu, Apr 29, 2010 at 5:00 PM, Philip Oliver >> <phil3(a)olivercomputing.com> wrote: >>> Christian, >>> >>> In light of the bug report, I updated my SVN repository copy and did a 'mvn install', and got the following errors in the automated tests: >>> >>> ------------------------------------------------------- >>> T E S T S >>> ------------------------------------------------------- >>> Running org.basex.test.query.NamespaceTest >>> Tests run: 4, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.418 sec <<< FAILURE! >>> Running org.basex.test.query.FTTest >>> Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.09 sec <<< FAILURE! >>> Running org.basex.test.cs.SemaphoreTest >>> Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.004 sec <<< FAILURE! >>> Running org.basex.test.cs.PermissionTest >>> BaseX 6.1.1 [Server] >>> >>> >>> >>> I don't know how significant these are, or if it's a result of me not properly building BaseX, but FYI. >>> >>> >> > >

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Re: [basex-talk] Strange query output
by Christian Grün 29 Apr '10

29 Apr '10

Dear Toon Calders, thanks for your detailed bug report. Yes, this was a serious issue; the predicate was optimized for an accessing the index, although it was dependent on the query context. This is now fixed in the repository version 6.1.1 of BaseX: http://basex.org/maven/org/basex/basex/6.1.1/ I've forwarded your mail to the mailing list to let others know about it as well. All the best, Christian On Thu, Apr 29, 2010 at 12:17 PM, Calders, T.G.K. <t.calders(a)tue.nl> wrote: > Dear BaseX developers, > > First of all, many thanks for making this nice tool freely available. I use > it in my Database class so the students can practice a bit with XPath and > XQuery and they are all, without any exception, very enthusiastic about the > tool. > > During class today, however, one of the students encountered a strange query > output; I reduced the example to its essence: > > For the following document: > > <errordoc> > <instructor fname="Toon" sname="Calders"/> > <lecturer fname="Toon" sname="Calders"/> > </errordoc> > > We ran the query “//instructor[@sname=../lecturer/@sname]” which returned > an empty answer when executed with BaseX 6.1. (with previous versions it > seems to work fine; e.g., 5.7). > > On the other hand, the query: > > let $x:=<errordoc> > <instructor fname="Toon" sname="Calders"/> > <lecturer fname="Toon" sname="Calders"/> > </errordoc> > > return $x//instructor[@sname=../lecturer/@sname] > > does return: > <instructor fname="Toon" sname="Calders"/> > > Best regards, > Toon Calders > TU Eindhoven ___________________________ Christian Gruen Universitaet Konstanz Department of Computer & Information Science D-78457 Konstanz, Germany Tel: +49 (0)7531/88-4449, Fax: +49 (0)7531/88-3577 http://www.inf.uni-konstanz.de/~gruen

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Re: [basex-talk] one question about Result and how to use it
by Beatriz Sancho 26 Apr '10

26 Apr '10

Thank you very much for the information i feel a little stupid because i usually think that i am understanding something and i am not.... now it works perfectly!! my application is for analyze student interactions in a social network, gives the results to the teacher in order to improve the collaborative learning, alerting them when some roles are detected (for example, an isolated student). All the interactions between students and documentes in bscw or in wikis are stored and some parsers transform it into a XML file, then my application have to analize that.... I will tell in my final doc why i have choosed Basex, and i will mention your efficiency and kindy. (sorry for my english again). 2010/4/26 Christian Grün <christian.gruen(a)gmail.com> > > I think you are confusing the database with the source document. > > The moment you add a document to your database there is no "link" to the > source document anymore. > > > > Once you perform update operations on a database the updates are > reflected only in the database. > > The (source) XML document is stored independently, this is why you call > export to overwrite your source XML file. > > Good hint! You can set the WRITEBACK flag to store changes in the > original documents by e.g.… > > new Set(Prop.WRITEBACK, true).execute(context); > > Christian >

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language binding for common lisp
by Andy Chambers 26 Apr '10

26 Apr '10

Hey All, I've recently discovered basex and it seems to be a pretty cool project. Thanks for making it open source. Here's a common lisp language binding to add to the mix. I developed it on sbcl against basex version 6.1 by transcribing the python version. Thanks again, Andy ;;; file: example.lisp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; (defpackage :basex-user (:use :cl :basex)) (in-package :basex-user) (time (let ((session (make-instance 'session))) (if (execute session "xquery 1 to 10") (print (result session)) (print (info session))) (close-session session))) ;;; file: basex-client.lisp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; (defpackage :basex (:use :cl :usocket) (:export :session :execute :close-session :info :result)) (in-package :basex) (defconstant +null+ (code-char 0)) (defclass session () ((host :initarg :host :initform "localhost") (port :initarg :port :initform 1984) (user :initarg :user :initform "admin") (pw :initarg :pw :initform "admin") (sock :initform nil) (result :initform nil :accessor result) (info :initform nil :accessor info))) (defmethod initialize-instance :after ((self session) &key) (with-slots (host port user pw sock) self (setf sock (socket-connect host port :element-type '(unsigned-byte 8))) (unless (hand-shake self) (error "Could not initiate connection")))) (defun hand-shake (session) (declare (optimize debug)) (labels ((md5 (str) (string-downcase (with-output-to-string (s) (loop for hex across (sb-md5:md5sum-string str) do (format s "~2,'0x" hex))))) (auth-token (pw timestamp) (md5 (format nil "~a~a" (md5 pw) timestamp)))) (with-slots (user pw sock) session (let* ((ts (read-null-terminated (socket-stream sock))) (auth (auth-token pw ts))) (write-null-terminated user (socket-stream sock)) (write-null-terminated auth (socket-stream sock)) (force-output (socket-stream sock)) (eq 0 (read-byte (socket-stream sock))))))) (defun read-null-terminated (in) (with-output-to-string (s) (loop for char = (code-char (read-byte in)) until (char= char +null+) do (write-char char s)))) (defun write-null-terminated (string out) (loop for char across string do (write-byte (char-code char) out)) (write-byte (char-code +null+) out)) (defmethod execute ((self session) query) (with-slots (sock) self (let ((stream (socket-stream sock))) (write-null-terminated query stream) (force-output stream) (setf (result self) (read-null-terminated stream) (info self) (read-null-terminated stream)) (eq 0 (read-byte (socket-stream sock)))))) (defmethod open-session ((self session)) (unwind-protect (unless (hand-shake self) (error "Could not open session")) (close-session self))) (defmethod close-session ((self session)) (with-slots (sock) self (write-null-terminated "exit" (socket-stream sock)) (socket-close sock))) -- ---- Andy Chambers Formedix Ltd

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google app engine
by Travis Webb 25 Apr '10

25 Apr '10

Has anyone on this list successfully installed BaseX onto the Google App Engine hosting platform? -tjw

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data import
by Jason Durham 22 Apr '10

22 Apr '10

Is there a way to import data from an existing base such as MS Excel or Access?

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BlueChillies.com - Software submitted
by BlueChillies.com 18 Apr '10

18 Apr '10

Thank you for your submission "BaseX" Please allow few days to review and publish your software. Best Regards, BlueChillies Team http://www.bluechillies.com/ © BlueChillies, 2000-2007

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Software Submitted - BaseX 6.1
by SoftList 18 Apr '10

18 Apr '10

Dear DBIS Group, University of Konstanz, Thank you for your submission - "BaseX 6.1" to SoftList. Please allow a few days until we review and place it on our site. Sincerely, SoftList.Net http://www.softlist.net � 2000-2008, SoftList.Net

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