Question

Using Oracle PLSQL, I have arrived at a point where i have generated a number of XML fragments of type XMLType. I have these stored in a VARRAY of type XMLTYPE. I can successfully print these out individually to a file.

What I want to do next is fuse all these fragments together and wrap them in another root element to generate a single document. From what I have read if I can get hold of an XMLSEQUENCETYPE then I can just pass this into XMLCONCAT(..) and it should return an XMLType concatenation of all the fragments. After this it’d just be a case of adding the root elements using XMLELEMENT(..). I am however, having difficulty finding a way of generating an XMLSEQUENCETYPE from my VARRAY of XMLTYPE.

Does anyone know how this can be done, and whether in fact the approach I have taken is the best one? (If anyone is curious, I’m trying to create a basic dbunit type framework. The intention of this script is to create a tool which can be used to output XML DataSets to file, which later get loaded into unit tests).

Here’s the plsql script:

set serveroutput on;
CREATE OR REPLACE TYPE rowset_query_type AS OBJECT ( 
   table_name          VARCHAR2(100),
   query_string        VARCHAR2(1024)
);
/

DECLARE

  TYPE XML_Fragments_Type IS VARRAY(1000) OF XMLTYPE;
  TYPE Rowset_Query_List_Type is VARRAY(1000) OF rowset_query_type;

  outputDir                 VARCHAR(200)  :=  'ORACLE_FILE_DIR';
  outputFile                VARCHAR(200)  :=  'TestDataSet.xml';

  qryCtx                    DBMS_XMLGEN.ctxHandle;
  rowsetResultFragments     XML_Fragments_Type;
  rowsetQueries             Rowset_Query_List_Type;  
  xmlResult                 xmltype;  
  rowsetQueryElement        rowset_query_type; 

  output                     CLOB;
BEGIN

 dbms_output.put_line('Exporting dataset...');

 -- export files to data fixture 

 -- define fixtures
 rowsetQueries := Rowset_Query_List_Type();
 rowsetQueries.EXTEND(2);

 rowsetQueries := Rowset_Query_List_Type(
 rowset_query_type('person', 'select * from person'),
 rowset_query_type('address','select * from address'));

 rowsetResultFragments := XML_Fragments_Type();
 rowsetResultFragments.EXTEND(rowsetQueries.count);

 FOR i IN rowsetQueries.FIRST..rowsetQueries.LAST 
 LOOP

  rowsetQueryElement := rowsetQueries(i);  
  dbms_output.put_line('Extracting dataset for table: ' || rowsetQueryElement.table_name || ' using query: ''' || rowsetQueryElement.query_string || '''');


  qryCtx := dbms_xmlgen.newContext(rowsetQueryElement.query_string);

  -- wrap the result up with a metadata tag containing the fixture tablename
  select xmlelement(
          "ROWSET_QUERY",
          xmlattributes(rowsetQueryElement.table_name as "tableName"),
              DBMS_XMLGEN.getXMLType(qryCtx)  
      )
  into rowsetResultFragments(i)
  from dual;

  --close context
  DBMS_XMLGEN.closeContext(qryCtx);

  -- print the results to console
  -- serialize the result for printing to output
  SELECT XMLSERIALIZE(
    CONTENT 
      rowsetResultFragments(i) 
    AS CLOB)
  INTO output
  FROM DUAL;

  DBMS_OUTPUT.PUT_LINE(output);

 END LOOP;




 -- concatenate the set of rowsetQueries result fragments to a single result clob
 --  ???

END;
/

Answer 1

you’re almost there.

first, change your type to an SQL one:

create or replace TYPE XML_Fragments_Type IS VARRAY(1000) OF XMLTYPE;
/

then do this

-- concatenate the set of rowsetQueries result fragments to a single result clob
 --  ???

 select xmlelement("root" ,xmlagg(column_value))
   into xmlresult
   from table(rowsetResultFragments);

eg:

    SQL> create or replace TYPE XML_Fragments_Type IS VARRAY(1000) OF XMLTYPE;
      2  /

    Type created.

    SQL> DECLARE
      2
      3    --TYPE XML_Fragments_Type IS VARRAY(1000) OF XMLTYPE;
      4    TYPE Rowset_Query_List_Type is VARRAY(1000) OF rowset_query_type;
      5
      6    outputDir                 VARCHAR(200)  :=  'ORACLE_FILE_DIR';
      7    outputFile                VARCHAR(200)  :=  'TestDataSet.xml';
      8
...
     26   rowsetQueries := Rowset_Query_List_Type(
     27   rowset_query_type('person', 'select table_name, owner from dba_tables where rownum = 1'),
     28   rowset_query_type('address','select owner, type_name, attributes from dba_types where rownum = 1'));
     29
...
     56
     57   select xmlelement("root" ,xmlagg(column_value))
     58     into xmlresult
     59     from table(rowsetResultFragments);
     60    SELECT XMLSERIALIZE(
     61      CONTENT
     62        xmlresult
     63      AS CLOB )
     64    INTO output
     65    FROM DUAL;
     66    DBMS_OUTPUT.PUT_LINE(output);
     67
     68
     69  END;
     70  /
    Exporting dataset...
    Extracting dataset for table: person using query: 'select table_name, owner from dba_tables where rownum = 1'
    Extracting dataset for table: address using query: 'select owner, type_name, attributes from dba_types where rownum = 1'
    <root>
      <ROWSET_QUERY tableName="person">
        <ROWSET>
          <ROW>
            <TABLE_NAME>ICOL$</TABLE_NAME>
            <OWNER>SYS</OWNER>
          </ROW>
        </ROWSET>
      </ROWSET_QUERY>
      <ROWSET_QUERY tableName="address">
        <ROWSET>
          <ROW>
            <OWNER>CTXSYS</OWNER>
            <TYPE_NAME>CATINDEXMETHODS</TYPE_NAME>
            <ATTRIBUTES>3</ATTRIBUTES>
          </ROW>
        </ROWSET>
      </ROWSET_QUERY>
    </root>