How to putXML on a joined View?

Question

Hi
I would like to insert an XML document into two tables (some
elements into table 1 and some into table 2). I have created a
joined view of the two tables and have tried to insert into the
view with:
java OracleXML putXML -user %USER_PASSWORD% -filename myfile.xml
myView
But I get the error "cannot modify a column which maps to a non
key-preserved table". PLEASE GIVE A SPECIFIC EXAMPLE OF AN
UPDATABLE 'VIEW' WHERE AN INSERT CAN MODIFY MORE THAN ONE
UNDERLYING TABLE. Is it possible?
Any example will do. But here is what I tried to do. I tried
to map the first few ROW child elements of an XML document (shown
at the bottom) into columns of the EMP table and the remaining
child
elements into another table called RELATIVE (this is a table
containing next-of-kin contact information for each employee). I
created a RELATIVE table with:
CREATE TABLE RELATIVE (
IDREL NUMBER(15) PRIMARY KEY,
EMPNUM NUMBER(4) CONSTRAINT FK_REL REFERENCES SCOTT.EMP(EMPNO),
RNAME VARCHAR2(20) NOT NULL,
TEL NUMBER(14),
STREET VARCHAR2(30),
CITY VARCHAR2(20),
STATE VARCHAR2(10),
ZIP VARCHAR2(12),
COUNTRY VARCHAR2(20)
I added a EMPNO_DUP column to the EMP table that is a copy of
the
EMPNO primary key (I did this so as to use EMPNO_DUP for the two
table join, rather than the EMPNO primary key. My first attempts
to make the joined view with EMPNO also gave the same error). I
wrote a PL/SQL trigger than would make sure that EMPNO_DUP and
EMPNO remain in synch if EMPNO is updated or if there is an
INSERT on EMP. Then I created a joined view of EMP and RELATIVE
with:
CREATE OR REPLACE VIEW EMPREL
(EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO, EMPNO_DUP
IDREL, EMPNUM, RNAME, TEL, STREET, CITY, STATE, ZIP, COUNTRY)
AS SELECT
E.EMPNO, E.ENAME, E.JOB, E.MGR, E.HIREDATE, E.SAL, E.COMM,
E.DEPTNO,E.EMPNO_DUP,
R.IDREL, R.EMPNUM, R.RNAME, R.TEL, R.STREET, R.CITY, R.STATE,
R.ZIP, R.COUNTRY
FROM EMP E, RELATIVE R WHERE E.EMPNO_dup=R.EMPNUM;
I tried to insert the XML document shown at the bottom with:
java OracleXML putXML -user %USER_PASSWORD% -filename myfile.xml
myView
I also tried the direct SQL command:
INSERT INTO EMPREL
(EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO,EMPNO_DUP,
IDREL, EMPNUM, RNAME, TEL, STREET, CITY, STATE, ZIP, COUNTRY)
VALUES
(7944, 'WIZARD', 'CLERK', 7782, '25-JUL-82', 1325, 0, 10, 7944,
1, 7944, 'SUE', 4087200111, '200 MAIN ST.', 'PALO ALTO', 'CA',
'94043', 'USA')
Both attempts resulted in this error message:
"cannot modify a column which maps to a non key-preserved table"
I would really appreciate an example of how to create an
updatable view where two or more underlying tables can be
modified. Thanks.
Regards
Mehran Moshfeghi
Here is the sample XML file. I want the first set of elements to
map to EMP table columns and the second set of elements (after
the blank line) to map to the RELATIVE table columns.
<?xml version="1.0"?>
<ROWSET>
<ROW>
<EMPNO>7942</EMPNO>
<ENAME>GUNNEL</ENAME>
<JOB>CLERK</JOB>
<MGR>7782</MGR>
<HIREDATE>1982-02-25 00:00:00.0</HIREDATE>
<SAL>1350</SAL>
<DEPTNO>10</DEPTNO>
<EMPNO_DUP>7942</EMPNO_DUP>
<IDREL>2</IDREL>
<RNAME>SMITH</RNAME>
<TEL>6504262551</TEL>
<STREET>2171 LANDINGS DRIVE</STREET>
<CITY>MOUNTAIN VIEW</CITY>
<STATE>CA</STATE>
<ZIP>94043-0837</ZIP>
<COUNTRY>USA</COUNTRY>
</ROW>
</ROWSET>
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Answer 1

Hi Mehran,
This is a classic view update problem where the database cannot
figure out automatically which table(s) to update given a join
view. Any update/insert/delete cannot act on more than one
table.So if you are updating a column in a join-view, then that
column must map to a particular column of a single table
unambigously. You should look at the documentation on updatable
join views.
One of the easiest solutions to your problem is to create
INSTEAD-OF trigger on those views. INSTEAD-OF triggers are
triggers that can be created over non-updatable views to make
them updatable. Here in the trigger body you specify the
appropriate insert statements into the base tables. So your view
can be as complicated as possible and yet updatable using these
triggers.
Thx
oracle XML team
Mehran (guest) wrote:
: Hi
: I would like to insert an XML document into two tables (some
: elements into table 1 and some into table 2). I have created a
: joined view of the two tables and have tried to insert into
the
: view with:
: java OracleXML putXML -user %USER_PASSWORD% -filename
myfile.xml
: myView
: But I get the error "cannot modify a column which maps to a
non
: key-preserved table". PLEASE GIVE A SPECIFIC EXAMPLE OF AN
: UPDATABLE 'VIEW' WHERE AN INSERT CAN MODIFY MORE THAN ONE
: UNDERLYING TABLE. Is it possible?
: Any example will do. But here is what I tried to do. I tried
: to map the first few ROW child elements of an XML document
(shown
: at the bottom) into columns of the EMP table and the remaining
: child
: elements into another table called RELATIVE (this is a table
: containing next-of-kin contact information for each employee).
I
: created a RELATIVE table with:
: CREATE TABLE RELATIVE (
: IDREL NUMBER(15) PRIMARY KEY,
: EMPNUM NUMBER(4) CONSTRAINT FK_REL REFERENCES SCOTT.EMP
(EMPNO),
: RNAME VARCHAR2(20) NOT NULL,
: TEL NUMBER(14),
: STREET VARCHAR2(30),
: CITY VARCHAR2(20),
: STATE VARCHAR2(10),
: ZIP VARCHAR2(12),
: COUNTRY VARCHAR2(20)
: I added a EMPNO_DUP column to the EMP table that is a copy of
: the
: EMPNO primary key (I did this so as to use EMPNO_DUP for the
two
: table join, rather than the EMPNO primary key. My first
attempts
: to make the joined view with EMPNO also gave the same error).
I
: wrote a PL/SQL trigger than would make sure that EMPNO_DUP and
: EMPNO remain in synch if EMPNO is updated or if there is an
: INSERT on EMP. Then I created a joined view of EMP and
RELATIVE
: with:
: CREATE OR REPLACE VIEW EMPREL
: (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO, EMPNO_DUP
: IDREL, EMPNUM, RNAME, TEL, STREET, CITY, STATE, ZIP, COUNTRY)
: AS SELECT
: E.EMPNO, E.ENAME, E.JOB, E.MGR, E.HIREDATE, E.SAL, E.COMM,
: E.DEPTNO,E.EMPNO_DUP,
: R.IDREL, R.EMPNUM, R.RNAME, R.TEL, R.STREET, R.CITY, R.STATE,
: R.ZIP, R.COUNTRY
: FROM EMP E, RELATIVE R WHERE E.EMPNO_dup=R.EMPNUM;
: I tried to insert the XML document shown at the bottom with:
: java OracleXML putXML -user %USER_PASSWORD% -filename
myfile.xml
: myView
: I also tried the direct SQL command:
: INSERT INTO EMPREL
: (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO,EMPNO_DUP,
: IDREL, EMPNUM, RNAME, TEL, STREET, CITY, STATE, ZIP, COUNTRY)
: VALUES
: (7944, 'WIZARD', 'CLERK', 7782, '25-JUL-82', 1325, 0, 10, 7944,
: 1, 7944, 'SUE', 4087200111, '200 MAIN ST.', 'PALO
ALTO', 'CA',
: '94043', 'USA')
: Both attempts resulted in this error message:
: "cannot modify a column which maps to a non key-preserved
table"
: I would really appreciate an example of how to create an
: updatable view where two or more underlying tables can be
: modified. Thanks.
: Regards
: Mehran Moshfeghi
: Here is the sample XML file. I want the first set of elements
to
: map to EMP table columns and the second set of elements (after
: the blank line) to map to the RELATIVE table columns.
: <?xml version="1.0"?>
: <ROWSET>
: <ROW>
: <EMPNO>7942</EMPNO>
: <ENAME>GUNNEL</ENAME>
: <JOB>CLERK</JOB>
: <MGR>7782</MGR>
: <HIREDATE>1982-02-25 00:00:00.0</HIREDATE>
: <SAL>1350</SAL>
: <DEPTNO>10</DEPTNO>
: <EMPNO_DUP>7942</EMPNO_DUP>
: <IDREL>2</IDREL>
: <RNAME>SMITH</RNAME>
: <TEL>6504262551</TEL>
: <STREET>2171 LANDINGS DRIVE</STREET>
: <CITY>MOUNTAIN VIEW</CITY>
: <STATE>CA</STATE>
: <ZIP>94043-0837</ZIP>
: <COUNTRY>USA</COUNTRY>
: </ROW>
: </ROWSET>
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