XML and ORACLE

Rosa Isela López Aguilar

Noviembre 2008

Oracle XML DB

Oracle Database supports native XML generation. Oracle provides you with several options for generating or regenerating XML data when stored in:

Oracle Database, in general

Oracle Database in XMLTypes columns and tables

Creating a Table with an XMLType Column

CREATE TABLE Ejemplo1(KEYVALUE varchar2(10) primary key, XMLCOLUMN xmltype);

select * from Ejemplo1;

Creating a Table of XMLType

CREATE TABLE XMLTABLE OF XMLType;

select * from XMLTABLE;

INSERT INTO ejemplo1 VALUES(100, XMLType('<Warehouse whNo="100"><Building>Owned</Building></Warehouse>'));

select * from ejemplo1;

Inserting Values on Ejemplo1

INSERT INTO ejemplo1 VALUES(101, XMLType('<PurchaseOrder xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://www.oracle.com/xdb/po.xsd"> <Reference>ADAMS-20011127121040988PST</Reference> <Actions> <Action> <User>SCOTT</User> <Date>2002-03-31</Date> </Action> </Actions> <Reject/> <Requestor>Julie P. Adams</Requestor> <User>ADAMS</User> <CostCenter>R20</CostCenter> <ShippingInstructions> <name>Julie P. Adams</name> <address>Redwood Shores, CA 94065</address> <telephone>650 506 7300</telephone> </ShippingInstructions> <SpecialInstructions>Ground</SpecialInstructions> <LineItems> <LineItem ItemNumber="1"> <Description>The Ruling Class</Description> <Part Id="715515012423" UnitPrice="39.95" Quantity="2"/> </LineItem> <LineItem ItemNumber="2"> <Description>Diabolique</Description> <Part Id="037429135020" UnitPrice="29.95" Quantity="3"/> </LineItem> <LineItem ItemNumber="3"> <Description>8 1/2</Description> <Part Id="037429135624" UnitPrice="39.95" Quantity="4"/> </LineItem> </LineItems></PurchaseOrder>'));

select * from ejemplo1;

Inserting Values on Ejemplo1

existsNode() Examples That Find a Node to Match the XPath Expression

Given this sample XML document, the following existsNode() operators return true (1).

SELECT existsNode(XMLCOLUMN,'/PurchaseOrder/Reference') FROM ejemplo1;

SELECT existsNode(XMLCOLUMN,'/PurchaseOrder[Reference="ADAMS-20011127121040988PST"]') FROM ejemplo1;

SELECT existsNode(XMLCOLUMN, '/PurchaseOrder/LineItems/LineItem[2]/Part[@Id="037429135020"]') FROM ejemplo1;

SELECT existsNode(XMLCOLUMN, '/PurchaseOrder/LineItems/LineItem[Description="8 1/2"]') FROM ejemplo1;

Overview of Generating XML Using Standard SQL/XML Functions

You can generate XML data using any of the following standard SQL/XML functions supported by Oracle XML DB:

XMLELEMENT and XMLATTRIBUTES SQL Functions XMLFOREST SQL Function XMLCONCAT SQL Function XMLAGG SQL Function XMLPI SQL Function XMLCOMMENT SQL Function XMLROOT SQL Function XMLSERIALIZE SQL Function XMLPARSE SQL Function

SELECT XMLCOLUMN, XMLELEMENT("emp", KEYVALUE) AS "result" FROM ejemplo1 WHERE KEYVALUE > 100;

XMLELEMENT

XMLElement(): Generating Nested XML

SELECT XMLELEMENT("Emp", XMLELEMENT("name", XMLCOLUMN), XMLELEMENT ( "emp", KEYVALUE)) AS "result" FROM ejemplo1 WHERE KEYVALUE > 100 ;

XMLElement(): Generating an Element for Each Employee with ID Attribute

SELECT XMLELEMENT("Emp", XMLATTRIBUTES(KEYVALUE AS "ID") ) AS "result" FROM ejemplo1 WHERE KEYVALUE > 100;

SELECT extract(XMLCOLUMN,'/emp//enumber') FROM ejemplo1;

XML EXTRACT

Using existsNode() in the WHERE Clause

SELECT count(*) FROM ejemplo1 WHERE existsNode(XMLCOLUMN,'/PurchaseOrder[User="ADAMS"]') = 1;

DELETE FROM ejemplo1 WHERE existsNode(XMLCOLUMN,'/PurchaseOrder[User="ADAMS"]') = 1;

Using delete in the WHERE Clause

XMLELEMENT: Generating an Element for Each Employee

This example produces an Emp element for each employee, with the employee name as its content:

SELECT e.employee_id, XMLELEMENT ("Emp", e.first_name ||' '|| e.last_name) AS "RESULT" FROM hr.employees e WHERE employee_id > 200;

This query produces the following typical result:

EMPLOYEE_ID RESULT----------- ----------------------------------- 201 <Emp>Michael Hartstein</Emp> 202 <Emp>Pat Fay</Emp> 203 <Emp>Susan Mavris</Emp> 204 <Emp>Hermann Baer</Emp> 205 <Emp>Shelley Higgins</Emp> 206 <Emp>William Gietz</Emp>

SELECT KEYVALUE, XMLELEMENT("NUEVO", KEYVALUE||' '||XMLCOLUMN) AS "RESULT" FROM ejemplo2 WHERE KEYVALUE=101;

XMLELEMENT: Generating an Element for a Particular Case

XMLELEMENT: Generating Nested XML

To produce an Emp element for each employee, with elements that provide the employee name and hire date, do the following:

SELECT XMLElement("Emp", XMLElement("name", e.first_name ||' '|| e.last_name), XMLElement("hiredate", e.hire_date)) AS "RESULT" FROM hr.employees e WHERE employee_id > 200 ;

RESULT-----------------------------------------------------------------------<Emp><name>Michael Hartstein</name><hiredate>1996-02-17</hiredate></Emp><Emp><name>Pat Fay</name><hiredate>1997-08-17</hiredate></Emp><Emp><name>Susan Mavris</name><hiredate>1994-06-07</hiredate></Emp><Emp><name>Hermann Baer</name><hiredate>1994-06-07</hiredate></Emp>

XMLELEMENT: Generating Employee Elements with ID and Name Attributes

This example produces an Emp element for each employee, with an id and name attribute:

SELECT XMLElement("Emp", XMLAttributes( e.employee_id as "ID", e.first_name ||' ' || e.last_name AS "name")) AS "RESULT" FROM hr.employees e WHERE employee_id > 200;

RESULT-----------------------------------------------<Emp ID="201" name="Michael Hartstein"></Emp><Emp ID="202" name="Pat Fay"></Emp><Emp ID="203" name="Susan Mavris"></Emp><Emp ID="204" name="Hermann Baer"></Emp><Emp ID="205" name="Shelley Higgins"></Emp><Emp ID="206" name="William Gietz"></Emp>

XMLELEMENT: Generating an Element from a User-Defined Datatype Instance

CREATE OR REPLACE TYPE emp_t AS OBJECT ("@EMPNO" NUMBER(4), ENAME VARCHAR2(10));

CREATE OR REPLACE TYPE emplist_t AS TABLE OF emp_t;

CREATE OR REPLACE TYPE dept_t AS OBJECT ("@DEPTNO" NUMBER(2), DNAME VARCHAR2(14), EMP_LIST emplist_t);

SELECT XMLElement("Department", dept_t(department_id, department_name, CAST(MULTISET(SELECT employee_id, last_name FROM hr.employees e WHERE e.department_id = d.department_id) AS emplist_t))) AS deptxml FROM hr.departments d WHERE d.department_id = 10;

This produces an XML document which contains the Department element and the canonical mapping of type dept_t.

DEPTXML-------------<Department> <DEPT_T DEPTNO="10"> <DNAME>ACCOUNTING</DNAME> <EMPLIST> <EMP_T EMPNO="7782"> <ENAME>CLARK</ENAME> </EMP_T> <EMP_T EMPNO="7839"> <ENAME>KING</ENAME> </EMP_T> <EMP_T EMPNO="7934"> <ENAME>MILLER</ENAME> </EMP_T> </EMPLIST> </DEPT_T></Department>

Accessing a Text Node Value Matching an XPath Expression Using extractValue()

SELECT extractValue(XMLCOLUMN,'/PurchaseOrder/Reference') FROM ejemplo1;

SELECT extractValue(XMLCOLUMN,'/Description') FROM ejemplo1, TABLE ( xmlsequence (extract(XMLCOLUMN,'/PurchaseOrder/LineItems/LineItem/Description') ) ) t;

Using updateXML() to Replace Contents of a Node Tree Associated with XPath Elements

In this example updateXML() replaces the contents of the node tree associated with the element identified by the XPath expression `/PurchaseOrders/LineItems/LineItem[2]'.

UPDATE ejemplo1 SET xmlcolumn = updateXML(xmlcolumn, '/PurchaseOrder/LineItems/LineItem[2]', xmltype('<LineItem ItemNumber="4"> <Description>Andrei Rublev</Description> <Part Id="715515009928" UnitPrice="39.95" Quantity="2"/> </LineItem>' ) ) WHERE existsNode(XMLCOLUMN, '/PurchaseOrder[Reference="MILLER-200203311200000000PST"]' ) = 1;SELECT * FROM ejemplo1;

Using updateXML() to Update a Text Node Value Identified by an XPath Expression

This example uses updateXML() to update the value of the text node identified by the XPath expression `/PurchaseOrder/Reference':

UPDATE ejemplo1 SET XMLCOLUMN = updateXML(XMLCOLUMN,'/PurchaseOrder/Reference/text()', 'MILLER-200203311200000000PST') WHERE existsNode(XMLCOLUMN,'/PurchaseOrder[Reference="ADAMS-20011127121040988PST"]') = 1;

SELECT * FROM ejemplo1;

XMLFOREST: Generating Elements with Attribute and Child Elements

This example generates an Emp element for each employee, with a name attribute and elements with the employee hire date and department as the content.

SELECT XMLElement("Emp", XMLAttributes(e.first_name ||' '|| e.last_name AS "name"), XMLForest(e.hire_date, e.department AS "department"))AS "RESULT" FROM employees e WHERE e.department_id = 20;

RESULT-------------------------------------<Emp name="Michael Hartstein"> <HIRE_DATE>1996-02-17</HIRE_DATE> <department>20</department></Emp><Emp name="Pat Fay"> <HIRE_DATE>1997-08-17</HIRE_DATE> <department>20</department></Emp>

XMLFOREST: Generating an Element from a User-Defined Datatype Instance

SELECT XMLForest( dept_t(department_id, department_name, CAST (MULTISET (SELECT employee_id, last_name FROM hr.employees e WHERE e.department_id = d.department_id) AS emplist_t)) AS "Department") AS deptxml FROM hr.departments d WHERE department_id=10;

DEPTXML---------------------------------<Department DEPTNO="10"> <DNAME>Administration</DNAME> <EMP_LIST> <EMP_T EMPNO="200"> <ENAME>Whalen</ENAME> </EMP_T> </EMP_LIST></Department>

SELECT XMLELEMENT("Emp", XMLFOREST(KEYVALUE, XMLCOLUMN)) "Emp Element" FROM ejemplo1 WHERE KEYVALUE > 99;

XMLFOREST

CREATE TABLE datosxml(Colxml XMLType);CREATE TABLE xsl_tab (col1 XMLTYPE);

Insert Into datosxml Values (xmltype('<empleado><nombre>Juan</nombre><apellido>garcia</apellido></empleado>'));

SELECT * FROM datosxml;

XMLTRANSFORM

Inserting StyleSheet:

INSERT INTO xsl_tab VALUES (XMLTYPE.createxml('<?xml version="1.0"?><xsl:stylesheet version="1.0"xmlns:xsl="http://www.w3.org/1999/XSL/Transform" ><xsl:output encoding="utf-8"/><!-- alphabetizes an xml tree --><xsl:template match="*"><xsl:copy><xsl:apply-templates select="*|text()"><xsl:sort select="name(.)" data-type="text"order="ascending"/></xsl:apply-templates></xsl:copy></xsl:template></xsl:stylesheet>'));

XMLTRANSFORM

SELECT XMLTRANSFORM(d.colxml, x.col1) FROM datosxml d, xsl_tab x;

Result XMLTRANSFORM

http://www.acs.ilstu.edu/docs/oracle/server.101/b10759/functions204.htm

http://lbd.epfl.ch/f/teaching/courses/oracle9i/appdev.920/a96620/xdb03usg.htm#1656

Referencias