Merging xml files element by lement

Question

Hi, I have two xml files of dept and emp tables. I want to merg these two xml files in such a way that the output should be grouped by deptnos.
i.e., under dept deptno 10 child node, i should get all emp child nodes who have deptno 10. How can I do this using DBMS_XMLDOM. Please help. Thank you.
dept xml -
<?xml version="1.0"?>
<DEPT_SET>
<DEPT>
<DEPTNO>10</DEPTNO>
<DNAME>ACCOUNTING</DNAME>
<LOC>NEW YORK</LOC>
</DEPT>
<DEPT>
<DEPTNO>20</DEPTNO>
<DNAME>RESEARCH</DNAME>
<LOC>DALLAS</LOC>
</DEPT>
<DEPT>
<DEPTNO>30</DEPTNO>
<DNAME>SALES</DNAME>
<LOC>CHICAGO</LOC>
</DEPT>
<DEPT>
<DEPTNO>40</DEPTNO>
<DNAME>OPERATIONS</DNAME>
<LOC>BOSTON</LOC>
</DEPT>
</DEPT_SET>
emp xml -
<?xml version="1.0"?>
<EMP_SET>
<EMP>
<EMPNO>7369</EMPNO>
<ENAME>SMITH</ENAME>
<JOB>CLERK</JOB>
<MGR>7902</MGR>
<HIREDATE>17-DEC-80</HIREDATE>
<SAL>800</SAL>
<DEPTNO>20</DEPTNO>
</EMP>
<EMP>
<EMPNO>7499</EMPNO>
<ENAME>ALLEN</ENAME>
<JOB>SALESMAN</JOB>
<MGR>7698</MGR>
<HIREDATE>20-FEB-81</HIREDATE>
<SAL>1600</SAL>
<COMM>300</COMM>
<DEPTNO>30</DEPTNO>
</EMP>
<EMP>
<EMPNO>7521</EMPNO>
<ENAME>WARD</ENAME>
<JOB>SALESMAN</JOB>
<MGR>7698</MGR>
<HIREDATE>22-FEB-81</HIREDATE>
<SAL>1250</SAL>
<COMM>500</COMM>
<DEPTNO>30</DEPTNO>
</EMP>
<EMP>
<EMPNO>7566</EMPNO>
<ENAME>JONES</ENAME>
<JOB>MANAGER</JOB>
<MGR>7839</MGR>
<HIREDATE>02-APR-81</HIREDATE>
<SAL>2975</SAL>
<DEPTNO>20</DEPTNO>
</EMP>
<EMP>
<EMPNO>7654</EMPNO>
<ENAME>MARTIN</ENAME>
<JOB>SALESMAN</JOB>
<MGR>7698</MGR>
<HIREDATE>28-SEP-81</HIREDATE>
<SAL>1250</SAL>
<COMM>1400</COMM>
<DEPTNO>30</DEPTNO>
</EMP>
<EMP>
<EMPNO>7698</EMPNO>
<ENAME>BLAKE</ENAME>
<JOB>MANAGER</JOB>
<MGR>7839</MGR>
<HIREDATE>01-MAY-81</HIREDATE>
<SAL>2850</SAL>
<DEPTNO>30</DEPTNO>
</EMP>
<EMP>
<EMPNO>7782</EMPNO>
<ENAME>CLARK</ENAME>
<JOB>MANAGER</JOB>
<MGR>7839</MGR>
<HIREDATE>09-JUN-81</HIREDATE>
<SAL>2450</SAL>
<DEPTNO>10</DEPTNO>
</EMP>
<EMP>
<EMPNO>7788</EMPNO>
<ENAME>SCOTT</ENAME>
<JOB>ANALYST</JOB>
<MGR>7566</MGR>
<HIREDATE>09-DEC-82</HIREDATE>
<SAL>3000</SAL>
<DEPTNO>20</DEPTNO>
</EMP>
<EMP>
<EMPNO>7839</EMPNO>
<ENAME>KING</ENAME>
<JOB>PRESIDENT</JOB>
<HIREDATE>17-NOV-81</HIREDATE>
<SAL>5000</SAL>
<DEPTNO>10</DEPTNO>
</EMP>
<EMP>
<EMPNO>7844</EMPNO>
<ENAME>TURNER</ENAME>
<JOB>SALESMAN</JOB>
<MGR>7698</MGR>
<HIREDATE>08-SEP-81</HIREDATE>
<SAL>1500</SAL>
<COMM>0</COMM>
<DEPTNO>30</DEPTNO>
</EMP>
<EMP>
<EMPNO>7876</EMPNO>
<ENAME>ADAMS</ENAME>
<JOB>CLERK</JOB>
<MGR>7788</MGR>
<HIREDATE>12-JAN-83</HIREDATE>
<SAL>1100</SAL>
<DEPTNO>20</DEPTNO>
</EMP>
<EMP>
<EMPNO>7900</EMPNO>
<ENAME>JAMES</ENAME>
<JOB>CLERK</JOB>
<MGR>7698</MGR>
<HIREDATE>03-DEC-81</HIREDATE>
<SAL>950</SAL>
<DEPTNO>30</DEPTNO>
</EMP>
<EMP>
<EMPNO>7902</EMPNO>
<ENAME>FORD</ENAME>
<JOB>ANALYST</JOB>
<MGR>7566</MGR>
<HIREDATE>03-DEC-81</HIREDATE>
<SAL>3000</SAL>
<DEPTNO>20</DEPTNO>
</EMP>
<EMP>
<EMPNO>7934</EMPNO>
<ENAME>MILLER</ENAME>
<JOB>CLERK</JOB>
<MGR>7782</MGR>
<HIREDATE>23-JAN-82</HIREDATE>
<SAL>1300</SAL>
<DEPTNO>10</DEPTNO>
</EMP>
</EMP_SET>
Required output is -
<?xml version="1.0"?>
<DEPT_SET>
<DEPT>
<DEPTNO>10</DEPTNO>
<DNAME>ACCOUNTING</DNAME>
<LOC>NEW YORK</LOC>
</DEPT>
<DEPT>
<DEPTNO>20</DEPTNO>
<DNAME>RESEARCH</DNAME>
<LOC>DALLAS</LOC>
</DEPT>
<EMP>
<EMPNO>7369</EMPNO>
<ENAME>SMITH</ENAME>
<JOB>CLERK</JOB>
<MGR>7902</MGR>
<HIREDATE>17-DEC-80</HIREDATE>
<SAL>800</SAL>
<DEPTNO>20</DEPTNO>
</EMP>
<DEPT>
<DEPTNO>30</DEPTNO>
<DNAME>SALES</DNAME>
<LOC>CHICAGO</LOC>
</DEPT>
<DEPT>
<DEPTNO>40</DEPTNO>
<DNAME>OPERATIONS</DNAME>
<LOC>BOSTON</LOC>
</DEPT>
</DEPT_SET>

Answer 1

Well, if you are building the dept and emp XML files yourself, then the easiest solution is to use one SQL/XML (XMLElement, XMLForest, XMLAgg) statement to build the required XML instead of building two pieces and trying to merge.
If you can't go that option, then you can use importNode and appendChild to insert your selected nodes into the correct spot in the main XML.
As a starter, here is a snippet of code that takes a single node from a temp DOMDocument and inserts it into the master DOMDocument at a certain location.
    l_inq_nodelist := dbms_xmldom.getelementsbytagname(l_temp_domdoc,
                                                       'theDesiredNode');
    l_inq_nl_len := xmldom.getlength(l_inq_nodelist);
    IF l_inq_nl_len > 0 THEN
       -- Take the node above and adopt it into the response document
       l_temp2_nd := dbms_xmldom.importNode(o_response_doc,
                                            dbms_xmldom.item(l_inq_nodelist, 0),
                                            TRUE);
       -- Put the node in the correct position in the response document                                          
       l_temp2_nd := xdb.dbms_xmldom.appendChild(l_rsp_msg_nd, l_temp2_nd);
    END IF;I know your situation is slightly different as you need to take multiple nodes but once you can select out your nodes from the emp XML, you can use the above to insert into the dept XML. I would provide more samples but it has been a while since I've read XML via DOMDocument as I use XMLType when reading XML. Feel free to post what you have if you get stuck.