Re: [basex-talk] Use xquery:eval in insert statement

Dear Jonas,

first of all, it may be advisable to avoid xquery:eval whenever possible, as queries without dynamic query evaluations can be optimized much better. You could e.g. rewrite your function code to something like..

let $name := node-name($input) return insert node $input after ( doc($document)//*[node-name() = $name][last()] )

..or even avoid the slow last() function call:

let $name := node-name($input) return insert node $input into ( doc($document)/*[node-name(*) = $name] )

Next, please note that the following query..

//Customer[last()]

..is equivalent to..

//descendant-or-self::node()/child::Customer[last()]

..and you are probably looking for..

//descendant::Customer[last()]

Sorry for teaching; let‘s go back to the reason why you actually wrote this mail.. ;) I couldn’t reproduce the issue you reported. Could you please provide me with a tiny "CustomersOrders.xml" instance, or check out if the problem persists with Version 7.7 [1]?

Thanks in advance, Christian

[1] http://files.basex.org/releases/latest/ ___________________________

On Fri, Apr 12, 2013 at 5:49 PM, Lauener Jonas jonas.lauener@fhnw.ch wrote:

I want to use xquery:eval in an insert statement: declare updating function local:insert($document as xs:string, $input as element()) { insert node $input after xquery:eval(fn:concat($document, '//', node-name($input), '[last()]')) };

let $input := <Customer CustomerID="IZZTT"><CompanyName>App</CompanyName><ContactName>Steve Jobs</ContactName><ContactTitle>CEO in Heaven</ContactTitle><Phone>(777) 7777777777</Phone><FullAddress><Address>Apple Road 3</Address><City>Cuppertino</City><Region>OR</Region><PostalCode>00000</PostalCode><Country>Heaven</Country></FullAddress></Customer>

return local:insert("doc('CustomersOrders.xml')", $input)

On the BaseX GUI it works fine, but if I want to use it with the Java Client, it fails. I use this code in Java: public final class InsertExample { /** Hidden default constructor. */ private InsertExample() {}

/** Session reference. */ static ClientSession session;

/**

• Main method.
• @param args command-line arguments

*/ public static void main(final String[] args) { try { // Create a client session with host name, port, user name and password session = new ClientSession("localhost", 1984, "admin", "admin");

  String command = "declare updating function local:insert($document as xs:string, $input as element()) {\n  insert node $input after xquery:eval(fn:concat($document, '//', node-name($input), '[last()]'))\n};\n\nlet $input := <Customer CustomerID=\"IZZTT\"><CompanyName>App</CompanyName><ContactName>Steve Jobs</ContactName><ContactTitle>CEO in Heaven</ContactTitle><Phone>(777) 7777777777</Phone><FullAddress><Address>Apple Road 3</Address><City>Cuppertino</City><Region>OR</Region><PostalCode>00000</PostalCode><Country>Heaven</Country></FullAddress></Customer>\n\nreturn local:insert(\"doc('CustomersOrders')\", $input)";
  System.out.println(command);

  XQuery xquery = new XQuery(command);
  System.out.println(session.execute(xquery));

  // close session
  session.close();
} catch(IOException e) {
  e.printStackTrace();
}

} }

When I run it, I get this exception: Version: BaseX 7.6 Java: Oracle Corporation, 1.7.0_11 OS: Windows 8, amd64 Stack Trace: java.lang.RuntimeException: Exclusive lock could not be acquired. org.basex.util.Util.notexpected(Util.java:53) org.basex.io.random.TableDiskAccess.lock(TableDiskAccess.java:151) org.basex.data.DiskData.startUpdate(DiskData.java:202) org.basex.query.up.DatabaseUpdates.startUpdate(DatabaseUpdates.java:158) org.basex.query.up.ContextModifier.apply(ContextModifier.java:86) org.basex.query.up.Updates.apply(Updates.java:120) org.basex.query.QueryContext.update(QueryContext.java:270) org.basex.query.QueryContext.value(QueryContext.java:255) org.basex.query.QueryContext.iter(QueryContext.java:240) org.basex.query.QueryProcessor.iter(QueryProcessor.java:76) org.basex.core.cmd.AQuery.query(AQuery.java:84) org.basex.core.cmd.XQuery.run(XQuery.java:22) org.basex.core.Command.run(Command.java:342) org.basex.core.Command.exec(Command.java:321) org.basex.core.Command.execute(Command.java:78) org.basex.server.ClientListener.run(ClientListener.java:145) at org.basex.server.ClientSession.receive(ClientSession.java:259) at org.basex.server.ClientSession.execute(ClientSession.java:162) at org.basex.server.ClientSession.execute(ClientSession.java:167) at org.basex.server.Session.execute(Session.java:37) at org.basex.examples.api.InsertExample.main(InsertExample.java:42)

Is this a bug in BaseX? Or how can I solve this issue?

Thanks, Jonas _______________________________________________ BaseX-Talk mailing list BaseX-Talk@mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk