XML with RDBMS

coping with the paradigm issue

XML Storage options

Incoming XML can be treated in different ways, depending on what your application needs:Store XML in OS File with a pointerBring the file,as is, into a table (CLOB)Read the file, and programmatically

break it up and put into relational storage

Store in a XMLDB repository

Oracle XML DB White Paperhttp://otn.oracle.com/tech/xml/xmldb/pdf/XMLDB_Technical_Whitepaper.pdf

Tamino "Storing XML documents in a true native XML

data store integrated in an XML server is the key for to keeping pace with steadily increasing business dynamics. And it is the best way to respond to demands for maximum performance and scalability, with the lowest operational and administration costs"

http://www1.softwareag.com/Corporate/products/tamino/prod_info/default.asp

"Here's why you too should choose XML technology"

Tamino architecturehttp://www1.softwareag.com/Corporate/products/tamino/prod_info/architecture/default.asp

The Oracle approach

Generic approach

http://www.research.att.com/~sihem/shrex/shrex-widm2004.pdf

Doing XML in Oracle

XML_DB Getting XML out from Oracle Getting XML into Oracle

Procedural approachSQLLDR

Oracle XML Developer's Kit 10g

XML_DB

Oracle XML DB is fully compliant with the W3C XML data model

provides new standard access methods for XML navigation and query.

Not a Separate Database Server Technical white paper:

http://download-uk.oracle.com/technology/tech/xml/xmldb/current/twp.pdf

XML_DB features

XMLType is a native datatype extend CLOB datatype used to store and manage XML documents Columns

CREATE TABLE NewCDInfo (

DateTime_Recd Date DEFAULT SYSDATE, SourceFileName Varchar2(60), XMLContent XMLType) ;

or TablesCREATE TABLE CDXML of XMLType;

XML_DB features REGISTERING AN XML SCHEMA

XML Schema registered by calling the PL/SQL procedure: dbms_xmlschema.register_schema()

An XML Schema registration caused a default table to be created for each element in the XML Schema.

When an instance document is loaded in the Oracle XML_DB repository, the content of the document will be stored in the default table.

NOTE: tables created by this process are XMLType tables:

• Object tables where each row is represented as an instance of the XMLType datatype

XML_DB benefits

The ability to store and manage both structured and unstructured data under the same standard W3C XML data model (XML Schema).

Complete transparency and interchangeability between the XML and SQL data views.

FTP, and WebDAV protocol support. Store XML in the database and render it queryable and at

the same time access it through popular desktop tools. Claimed by XML_DB manual:

• (http://oracledocs.shu.ac.uk/oracle/10.1/GenericV1/appdev.101/b10790/xdb01int.htm#i1047230)

XML_DB uses include: Business-to-Business (B2B) and Application-to-Application (A2A)

integration Content-management applications Web Services A typical Oracle XML DB application has one or more of the following

requirements and characteristics: Large numbers of XML documents must be ingested or generated Large XML documents need to be processed or generated High performance searching, both within a document and across a

large collections of documents High Levels of security. Fine grained control of security Uses languages such as Java that support open standards such as

SQL, XML, XPath, and XSLT Accesses information using standard Internet protocols such as FTP,

HTTP/WebDAV, or JDBC Full queriability from SQL and integration with analytic capabilities Validation of XML documents is critical

http://oracledocs.shu.ac.uk/oracle/10.1/GenericV1/appdev.101/b10790/xdb02rep.htm#i1034512

XML_DB systems design factors:

Data Structured? Schema based?

Access How do applications get to the data? security

Application Language What are your organisations skillsets?

Performance issueshttp://oracledocs.shu.ac.uk/oracle/10.1/GenericV1/appdev.101/b10790/xdb02rep.htm#i1034512

Getting XML Out using XML SQL Utility (XSU).

XSU Java Servlet released Oracle8i In Oracle9i+ improved functionality

and PL/SQL APIs Two key packages:

DBMS_XMLQuery• getXML• getDTD

DBMS_XMLSave

Getting XML Out using XML SQL Utility (XSU). The basic stages of the procedure are:

Assign the Select that generates the data we want to the context called Qry

Use the DBMS_XMLQuery procedure called getXML to return the result set, and put the resultant CLOB into the pre-defined variable Members_xml.

Contexts need to be closed Return the generated CLOB as a result

From Table to XMLCREATE OR REPLACE FUNCTION membernames2xml RETURN CLOB IS members_xml CLOB; Qry DBMS_XMLQuery.ctxType;

BEGIN

Qry := DBMS_XMLQuery.newContext('SELECT * FROM member');

Members_xml := DBMS_XMLQuery.getXML(Qry);

DBMS_XMLQuery.closeContext(Qry);

RETURN members_xml ;

END;/

set pagesize 0

set long 10000

select '<?xml version="1.0"?>' from dual ;

select '<ROWSET>' from dual ;

SELECT

xmlelement("CD", xmlforest(a.composer, b.title, b.cdid))

FROM composers a, cds b

where a.composerid=b.composerid

and a.composerid < 10 ;

select '</ROWSET>' from dual ;

Outputing XML with XML_DB SQL extentions

IVY

To carry out the server-side procedures in the tutorial you need to have access to a folder that the Oracle Server can access

Log in to Ivy using Telnet and run: /usr/local/bin/oracle_dir

This process creates a Database Directory Object which maps to the user's home directory on ivy and the F: drive: /homedir/oracle_work

The Directory object has the following name: USERNAME_ORACLE_WORK For example: CMSPL4_ORACLE_WORK

Inserting to a table from XML

We can insert XML directly into a table of type XMLType: drop table CDXML ; CREATE TABLE CDXML of XMLType;

Declarethis_clob CLOB ;Beginthis_clob:=getclobfromfile('CMSPL4_ORACLE_WORK','Ne

wCD1471.xml');

INSERT INTO CDXML VALUES ( xmltype ( this_clob ) );END ;/• set long 1000• select * from CDXML ;

Inserting to a table from XML There are more steps involved than there

were for generating XML from SQL. We need to: read the XML file from the OS or URL PARSE it (make some sense of it) Put it in a memory structure that we can

manipulate it (a DOM document). Decide how we will handle the mapping to

fields And then insert the data

See example in tutorial