BaseX-Talk January 2017

basex-talk@mailman.uni-konstanz.de

30 participants
33 discussions

Counting
by meumapple 29 Jan '17

29 Jan '17

Hi, I have a structure like this: <c> <a>red</a> <a>red</a> <a>blue</a> <a>green</a> <a>green</a> </c> And I would like to get: <c> <a n="1">red</a> <a n="2">red</a> <a n="1">blue</a> <a n="1">green</a> <a n="2">green</a> </c> I have tried with two for loops after having identified the distinct-values(). This is in principle correct but it takes too long (I have many distinct values and a elements), because I cannot exit the for loop as soon as I get a match. I have been able to get the result with the window clause and then counting the elements of the window with a nested for-loop: is there an alternative solution? Thanks. Joseph

5 10

Importing XML using Java Classes vs Direct Commands
by Shaun Flynn 27 Jan '17

27 Jan '17

Hello there, I am attempting to create a database and add a resource to it programatically in Java. If I use this code: public static void main(String[] args) { try (ClientSession session = new ClientSession("localhost", 1984, "admin", "admin")) { session.execute("SET INTPARSE true"); session.execute("CREATE DB TESTING D:\\VP DB\\export.xml"); session.execute("CLOSE"); session.close(); } catch (IOException ex) { Logger.getLogger(BaseXTesting.class.getName()).log(Level.SEVERE, null, ex); } The code run's without a problem. When I attempt to do this: public static void main(String[] args) { // TODO code application logic here CreateDB createDBCmd = new CreateDB("TESTING"); Open openCmd = new Open("TESTING"); Add addCmd = new Add("\\BaseXTarget", "D:\\VP DB\\export.xml"); Set setCmd = new Set("INTPARSE", true); try (ClientSession session = new ClientSession("localhost", 1984, "admin", "admin")) { session.execute(setCmd); session.execute(openCmd); session.execute(addCmd); session.close(); } catch (IOException ex) { Logger.getLogger(BaseXTesting.class.getName()).log(Level.SEVERE, null, ex); } The following exception is thrown: run: Jan 26, 2017 5:03:17 PM basextesting.BaseXTesting main SEVERE: null org.basex.core.BaseXException: "BaseXTarget.xml" (Line 1): No text allowed before root element. at org.basex.api.client.ClientSession.receive(ClientSession.java:191) at org.basex.api.client.ClientSession.execute(ClientSession.java:160) at org.basex.api.client.ClientSession.execute(ClientSession.java:165) at org.basex.api.client.Session.execute(Session.java:36) at basextesting.BaseXTesting.main(BaseXTesting.java:36) BUILD SUCCESSFUL (total time: 0 seconds) It could be me being daft, but both pieces of code should achieve the same thing as they point to the same file, but when classes are used instead of command strings, the BaseXException is thrown. I have checked my data for the byte order mark, and have the ensure it is enoced using UTF-8. Help! Shaun

2 1

Any consideration given to something like XLP?
by Mike Engledew 26 Jan '17

26 Jan '17

Hello, I have been giving some thought to concurrency and rollback/recovery as we continue to evolve our Java EE application that uses BaseX as its XQuery, (XQuery update facility) engine. >From reading the BaseX Transactions section I concluded that BaseX locking is done at the database level. I can imagine this could ultimately become the major bottleneck in a "reactive cloud" application, has anyone considered the value of implementing a more granular locking mechanism like XLP (Xpath Locking Protocol) on which several academic papers have been written? Are there any similar ideas on the horizon for transactional commit/rollback for XML data? Thanks to the group (and Christian in particular) for such great help, advice and support. Mike.

2 1

Memory management
by meumapple 24 Jan '17

24 Jan '17

I have 223 XML files and I need to perform some actions on each of them, so that the output should be the modified texts (223 new files). What I have noticed is that if I apply my script recursively to each file and then save the results in new files (file:write()), everything works fast. On the other hand, If I do not write out the results in new files (but I expect the results from all the files in the GUI), the GUI freezes and then runs out of memory. My question is: is there a way to get the script working well without using file:write()? Should I always apply this script strategy when I work with many files? Thanks, Joseph

2 5

basex, nfs, and local storage
by Baysdon, Joseph 24 Jan '17

24 Jan '17

My baseX database is accessed via an NFS mount, and I’d like to improve its performance by moving its re-creatable files (e.g. indices) to a local disk. For the sake of NFS backup & restore, I’d like to keep the db files which cannot be re-created on the NFS servers. Would someone please identify which db files I can move to a local disk, and which files cannot be re-created and therefore, must remain on NFS? Thanks, Joe

2 7

RestXQ returning JSON
by Marco Lettere 24 Jan '17

24 Jan '17

Hello all, this morning just stumbled into this issue and I'm wondering whether it could be somehow smoothed up ... I have the following RestXQ function: declare %rest:path("/f") %rest:GET %output:method("json") function a:f() { (:code ...:) }; 1) Replacing comment with the following code correctly returns an empty object: let $out := (<json type="object"></json>) return $out 2) Replacing comment with the following code correctly returns an expected exception (" [SERE0023] Only one item can be serialized with JSON." : let $out := (<json type="object"></json>, <json type="object"></json>) return $out 3) Replacing comment with the following code returns a somewhat less expected Null-pointer exception : let $out := (<json type="object"></json>, <json type="object"></json>) return array{$out} 4) In order to get the expected Json array I need to write the code like the following: let $out := (<json type="object"></json>, <json type="object"></json>) return array{ $out ! json:parse(json:serialize(.), map{ "format" : "map"}) } I'm not sure whether the array could be inferred from the sequence directly in a pattern like 2. But I would expect that 3) should work. Isn't it? Thanks for any explanation. Regards, Marco.

3 3

Progress monitoring of XML import
by Shaun Flynn 23 Jan '17

23 Jan '17

Hello there, I am writing an application using JavaFx 8. A facility I would like to have is a progress bar showing how the db:add command is running, similar to what the Basex GUI shows when creating a new database. Is it possible to send updates from BaseX to another application? Shaun

2 1

Losing some space entities
by France Baril 20 Jan '17

20 Jan '17

Hi, When I serialize content to HTML5, I lose some entities. xquery: adds '‍' in front of some content and outputs html html: should have '&zwj;', but doesn't. I've tried with 8204 and even the half space 8201. The only special space that seems to work is  , but it won't do for what I need right now. Code sample: *let* *$target-table* := *copy* *$copy* := *$base-table* *modify*( *for **$td* *in **$copy*//*tr*/*td*[*position*()= *$column-to-filter-by*] *let* *$new-value* := ('‍', *for **$node* *in **$td*/*node*() *return **$node*) *return replace* *value* *of* *node* *$td* *with **$new-value* ) *return **$copy* *return * *$target-table* Is there any way to solve this? -- France Baril Architecte documentaire / Documentation architect france.baril(a)architextus.com

3 11

fn:unparsed-text fails in command line XQuery
by Gunther Rademacher 20 Jan '17

20 Jan '17

Hello list, I have a file some.xml containing <xml>hello world!</xml> and I can read it in BaseX code like this: java org.basex.BaseX "declare namespace fn='http://www.w3.org/2005/xpath-functions';fn:doc('some.xml')" However I cannot use fn:unparsed-text() from a command line, when a namespace declaration with a protocol is present. I have tried to do java org.basex.BaseX "declare namespace fn='http://www.w3.org/2005/xpath-functions';fn:unparsed-text('some.xml')" but I keep getting this: Stopped at ., 1/79: [FOUT1170] Static Base URI is undefined. This is strange, because the command works fine without the namespace declaration: java org.basex.BaseX "unparsed-text('some.xml')" What can I do to use both namespace declarations and fn:unparsed-text from within a single command line? Best regards Gunther

2 2

Access-Control-Allow-Origin
by lambert strether 18 Jan '17

18 Jan '17

Hi: This is probably an extremely newbie-ish question. I'm developing on localhost using MAMP/PHP at port 8888, and basex at port 8984. So I am running into "Cross-Origin Resource Sharing" issues, apparently, when I have the PHP server issue an XMLHttpRequest to the Basex server. I would have thought that this line in my REST GET function %rest:header-param("Access-Control-Allow-Origin", "http://localhost:8888") in my *.xqm file would have solved the problem. Instead, I'm getting this error: 400 (Stopped at /Users/shunting/basex/webapp/restxq.xqm, 395/14: [bxerr:BASX0003] Invalid path template: "http://localhost:8888".) I'm stymied because I don't see how a URL could match a path template in the first place. Is the "Access-Control-Allow-Origin" not a supported parameter? All I want to do is get my two servers on my machine to talk to each other. If this isn't the right way, is there another one? Thank you! * * * Every communication from this account is off the record, unless explicitly put on the record.

2 1

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BaseX-Talk January 2017