XQuery query over just one single xml file returns data but query over lots of XML didn't return any data.

Question

Hello,
Please, help me.
I am depending on this query working fine to complete a academic task.
On the Oracle xml database Express version 11.2.0.2.0 I used data from wikipedia to populate my table of XML files and W3C use case as a query model (XQuery and XPath Full Text 1.0 Use Cases).
I have a table with 26.416 split xml files into some xml columns, it is about 512 MB.
CREATE TABLE tb_wikipedia_inex (DOC VARCHAR(30) NOT NULL,
                                XML XMLTYPE,
                                PRIMARY KEY (DOC)
I want to perform a query (full text) on all those files but when I execute a xquery it retuns nothing or warnings. Unfortunatelly I understand nothing from trace file.
SQLPLUS:
XQUERY  fn:collection("oradb:/HR/TB_INEX2009")//article//language  [ora:contains(., "java") > 0]
TRACE FILE:
System altered.
Elapsed: 00:00:42.08
Session altered.
Elapsed: 00:00:00.00
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.00
Elapsed: 00:00:00.05
Execution Plan
Plan hash value: 1500681423                                                                      
| Id  | Operation                           | Name                   | Rows  | Bytes | Cost (%CPU)|
Time     |                                                                                       
|   0 | SELECT STATEMENT                    |                        |  8168 | 16336 |    29   (0)|
00:00:01 |                                                                                       
|   1 |  COLLECTION ITERATOR XMLSEQ FETCH   | XMLSEQUENCEFROMXMLTYPE |  8168 | 16336 |    29   (0)|
00:00:01 |                                                                                       
|   2 |   SORT AGGREGATE                    |                        |     1 |     2 |            |
         |                                                                                       
|*  3 |    COLLECTION ITERATOR PICKLER FETCH| XMLSEQUENCEFROMXMLTYPE |   408 |   816 |    66  (57)|
00:00:01 |                                                                                       
Predicate Information (identified by operation id):                                              
   3 - filter(SYS_XMLCONTAINS(SYS_XQ_UPKXML2SQL(SYS_XQEXVAL(SYS_XQEXTRACT(SYS_XQCON2SEQ(VALUE(KOKBF$
              ,'/language/text()'),1,50),50,1,0),'java')>0)                                      
Note                                                                                             
   - Unoptimized XML construct detected (enable XMLOptimizationCheck for more information)       
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.00
How can I execute xquery over a bunch of xml files to obtain xml data?
Regards,
Daiane

Answer 1

Hello,
I was trying to find what is the problem, but without success.
The most simple test don't work.
So, I created a new table with few xml files to reproduce the query.
Below are my scripts:
XML COLUMN  SQLPLUS
CREATE TABLE HR.tb_xml (DOC VARCHAR(30) NOT NULL,
                                           XML XMLTYPE,PRIMARY KEY (DOC))
CREATE INDEX HR.Ixml_tb_xml ON HR.tb_xml (XML)  INDEXTYPE IS XDB.XMLINDEX  PARAMETERS ('PATHS (INCLUDE(//article
                                                                                                                   //article/physical_entity/communicator/person/compiler/causal_agent/language))')
CREATE INDEX Itxt_tb_xml1  ON HR.tb_xml (XML)  INDEXTYPE IS CTXSYS.CONTEXT;
Shell:
nohup sqlldr daiane/daiane DIRECT=false PARALLEL=false control = load_xml.ctl;
XML TABLE SQLPLUS:
create table livros of XMLTYPE;
Shell:
nohup sqlldr daiane/daiane DIRECT=false PARALLEL=false control = load_xmltb.ctl;
XML Files:
https://www.dropbox.com/sh/sn26jq6fjoi4635/0wjJI6tT4h
Queries:
for XQUERY  fn:collection("oradb:/HR/TB_XML")//article/physical_entity/communicator/person/compiler/causal_agent/language/writer/header/categories/category [ora:contains(., "PHP") > 0]
XQUERY  fn:collection("oradb:/HR/TB_XML")//article/physical_entity/communicator/person/compiler/causal_agent/language/writer/header/title [ora:contains(text(), "PHP") > 0]
for XQUERY  fn:collection("oradb:/HR/LIVROS")//article/physical_entity/communicator/person/compiler/causal_agent/language/writer/header/categories/category [ora:contains(., "PHP") > 0]
XQUERY  fn:collection("oradb:/HR/LIVROS")//article/physical_entity/communicator/person/compiler/causal_agent/language/writer/header/title [ora:contains(text(), "PHP") > 0]
What is wrong with these queries?
Regards,
Daiane