<ORACLE XML DB>
<Author fullName=‘Marouane Bouzoubaa’/>
<Course title=‘XML & Data Management ‘/>
<Supervisor fullName=‘Dr. Hachim Haddouti’/>
</ORACLE XML DB>
Outline
► Why XML in the Database
► What is XML DB?
► XML DB Architecture
► The XMLType Datatype
► Example1:
 Schemas Registration
 Inserting and Querying Data
 Creating and Using Indices
► The XML DB Repository
► The XML DB APIs
► XML Future Additions
► Summary
Common XML Architectures
Why XML in the Database?
► Reduce
maintenance costs of extra moving parts;
i.e. XML middleware.
 Eliminate separate ‘XML-processing’ layers
► Keep
applications standards-based
 W3C, IETF, ANSI/ISO, J2EE
 Eliminate proprietary file formats, message formats,
delimited columns
► Enable
richer semantics and better management
for content-oriented applications
 Store as XML vs. Files or LOBs
 Queryability
Oracle and XML
► Oracle
has been at the forefront of XML
technology for quite a while.
► From the beginning Oracle implemented the
various different XML standards, which have
largely been defined by the W3C.
► Oracle XML parser: SAX and DOM APIs.
► XSLT transformations and support for the
initial XML Schema proposals
► Etc… ahead of time.
ORACLE XML DB Features
► With
Oracle XML DB, you get all the advantages of
relational database technology and XML
technology at the same time.
► Oracle
XML DB provides an independent
infrastructure to store and manage XML data:
 storage-independent
 content-independent
 programming language-independent
ORACLE XML DB
► Oracle
XML DB is the term used to describe the
technology in the Oracle 9i Release 2 database for
supporting XML
► Extends the popular Oracle relational database
 Keeps all the functionality of RDBMS
 Provides all of the functionality associated with a
native XML database
► Delivers
XML.
high-performance storage and retrieval of
XML Support in Oracle 9i R2
XMLType
XML
Repository
XML DB Architecture - Data View
XML DB Architecture - Content View
The XMLType Datatype Definition
► “XMLType
is a native data-type
that is used to store and manage
XML documents in columns or
tables”
The XMLType Datatype
►Introduced
with Oracle 9i Rel. 1 to
store XML data in the database
►Enhanced extensively in 9i Rel. 2
► XMLType
is a native server data-type
 allows the database to understand that a
column or table contains XML
 same way as DATE data-type
The XMLType Datatype
► XMLType
is an object type
► In tables: xmltype can either be used
as data-type for a column or an entire
table
create table orders
(
orderNo NUMBER(10),
customerId NUMBER(8),
xmlorder XMLTYPE,
date_entered DATE
)
-------------------------------------create table orders of XMLTYPE
The XMLType Datatype
► XMLType
is an object type
 In PL/SQL: a parameter, a return value, a
PL/SQL table, a record or a variable can be
declared as an XMLTYPE
The XMLType Datatype
► The
XMLType data type can also be used
when defining views:
 XMLType view
 relational view that includes an XMLType column
► This
allows to expose content stored in
relational tables and external data sources
as XML documents.
The XMLType Datatype
► XMLType has a number of built-in member
functions for creating, extracting and
indexing XML data
► Allows access to the XML data using
standard XPath expressions
► A new 9.0.2 operator, XMLTransform,
allows for XSL transformations
► The XML data can optionally be based on
a W3C schema
The XMLType Member Functions
XML DB provides a number of functions for querying and
updating XML data. The most important of these
functions are:
extract(xmltype,xpath) extracts a subset of nodes, or an
XML fragment, from an XML document
► existsNode(xmltype,xpath) checks whether or not a particular
node exists in the XMLType, it is often found as part of a
WHERE clause statement
► extractValue(xmltype,xpath) extracts the value of a
single node in an XML document using an XPath
expression
► updateXML() updates an entire XML document or a
portion of the XML document in the database
►
The XMLType Member Functions
► schemaValidate() Validates the contents of
the XMLType against an XML Schema
► transform() XSL Transformation
► getClobVal()
Returns the document as a
CLOB.
► getNumVal() Returns the fragment or text
value in the XMLType to a number.
► getStringVal() Returns the document as a
string.
XMLType Data Storage
XMLType data can be stored in one
of two ways:
 In CLOB storage to maintain the
original XML content
 In Structured storage (tables and
views) to maintain DOM fidelity
►
XMLType Data Storage
► When
you create an XMLType column
without an XML schema, a hidden CLOB
column is automatically created
► The hidden column stores the extra nonSQL based information
CLOB VS. Structured Storage
XML Piecewise Update
► When
using Structured Storage:
 You can use XPath to specify individual elements
and attributes of your document to update, without
rewriting the entire document.
 This is more efficient, especially for large XML
documents.
XMLType Data Storage
► Constraining
a column or table to an XML
Schema has a number of advantages:
 The database will store only valid XML documents
 Oracle XML DB can use the information contained in
the XML Schema to provide more intelligent query
and update processing of the XML.
► One
important point to note: DTDs are not
supported.
XMLType: Virtual DOM
► DOM
problem: to operate on a document, the
whole document has to be an object model in
memory.
► With large documents, that can be a serious
problem.
► Virtual DOM: however, allows users to
materialize a DOM on the fly while processing
requests (a "virtual" or "lazy" DOM), rather than
doing it all at once; it only loads the data trees as
they are requested, throwing away previouslyreferenced sections of the document if memory
usage grows too large. This feature is completely
transparent.
XMLType: Schema Validation
► Oracle
XML DB does not automatically perform a
full schema validation of documents as they are
inserted into the database.
► Why?
► Schema validation is a fairly CPU intensive
operation.
► The development team decided to make full
schema validation optional.
► Full schema validation can be enabled on a
Schema by Schema basis using a Check
Constraint or Trigger.
XMLType: Schema Validation
► By
default, Oracle XML DB performs a light
weight validation of each document. It checks
that mandatory elements and attributes are
present, and that number of elements within
a collection is compliant with the values
defined in the XMLSchema
► It does not check pattern matches, minimum
lengths etc. This is a performance
optimization.
►XMLType
Datatype Example
Example: Scenario
 A mediator Company that offers many products
from different suppliers
 The client buys from different suppliers
Example: Steps To Accomplish
1. Register the XML schema with XML DB
► 2. Create a relational table to hold both relational
data and XML documents
► 3. Load an XML document into the table
► 4. Write an SQL query to retrieve
►
 Whole Document
 Data from both the relational fields and the XML
document in the same query
5. Update an XML field
6. Create Indexes
Example: Schema File
http://stud.alakhawayn.ma/~991BE740226/schema/order.xsd
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<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XMLSPY v5 rel. 3 U (http://www.xmlspy.com) by Marouane Bouzoubaa (AUI) -->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
<xs:element name="order">
<xs:complexType>
<xs:sequence>
<xs:element ref="fillByDate" minOccurs="0"/>
<xs:element name="items" type="itemsType"/>
</xs:sequence>
<xs:attribute name="orderNo" type="xs:positiveInteger"/>
</xs:complexType>
</xs:element>
<xs:complexType name="itemsType">
<xs:sequence>
<xs:element name="item" type="itemType" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="itemType">
<xs:sequence>
<xs:element ref="supplier"/>
<xs:element ref="itemNo"/>
<xs:element ref="unitCost"/>
<xs:element ref="qty"/>
</xs:sequence>
</xs:complexType>
<xs:element name="qty" type="xs:positiveInteger"/>
<xs:element name="supplier" type="xs:string"/>
<xs:element name="fillByDate" type="xs:date"/>
<xs:element name="itemNo" type="xs:string"/>
<xs:element name="unitCost">
<xs:simpleType>
<xs:restriction base="xs:decimal">
<xs:minInclusive value="0"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
</xs:schema>
Example: XML File
http://stud.alakhawayn.ma/~991BE740226/schema/order1.xml
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<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XMLSPY v5 rel. 3 U (http://www.xmlspy.com) by Marouane Bouzoubaa (AUI) -->
<order orderNo="104">
<fillByDate>2003-08-28</fillByDate>
<items>
<item>
<supplier>Miloud Company</supplier>
<itemNo>SL35-721</itemNo>
<unitCost>17.97</unitCost>
<qty>12</qty>
</item>
<item>
<supplier>Spezi Company</supplier>
<itemNo>CP01-487</itemNo>
<unitCost>162.75</unitCost>
<qty>5</qty>
</item>
<item>
<supplier>Kamal BO Company</supplier>
<itemNo>ML32-42</itemNo>
<unitCost>12.25</unitCost>
<qty>5</qty>
</item>
<item>
<supplier>Al-Watania Company</supplier>
<itemNo>KP96-351</itemNo>
<unitCost>16.70</unitCost>
<qty>5</qty>
</item>
<item>
<supplier>Bouchta Company</supplier>
<itemNo>CT01-365</itemNo>
<unitCost>62.05</unitCost>
<qty>5</qty>
</item>
</items>
</ order>
Registering a Schema
► Before
using an XML schema, it must be
registered with the database
► This
is accomplished using the
DBMS_XMLSCHEMA package
► The
two main functions are
registerSchema and deleteSchema
Registering an XML Schema
exec DBMS_XMLSCHEMA.registerSchema(
schema URL, schema source document)
► The
XML schema source document can
be define as a VARCHAR, a CLOB, an
XMLType or a URIType
► Registering an XML schema adds a
resource to the XML DB repository
► A Schema can be registered locally or
globally
Registering an XML Schema
► By
default, schemas are loaded locally and
associated with the “database schema” they
are created under
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BEGIN
DBMS_XMLSCHEMA.REGISTERSCHEMA(
schemaurl=>'http://stud.alakhawayn.ma/~991BE740226/schema/order.xsd',
schemadoc=>sys.UriFactory.getUri('http://stud.alakhawayn.ma/~991BE740226/sch
ema/order.xsd'));
END;
/
Creating a Relational Table with
XML Data
► create
table orders(
►orderNo
NUMBER(10),
►customerId NUMBER(8),
►xmlOrder XMLTYPE,
►date_entered
► XMLTYPE
DATE)
COLUMN xmlOrder
 STORE AS CLOB
 STORAGE (INITIAL 4096 NEXT 4096)
 XMLSCHEMA “http://stud.alakhawayn.ma/~991BE740226/schema/order.xsd”
ELEMENT “order”
 ;
Inserting, Querying and Updating
► XML
data is inserted into an XMLType column
using the XMLType() constructor
INSERT INTO ORDERS (orderNo,customerId,
xmlOrder, date_entered)
VALUES (orderNoSeq.nextval, 6135,
XMLTYPE(‘
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<order orderNo="104" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://stud.alakhawayn.ma/~991BE740226/schema/order.xsd">
<fillByDate>2003-08-28</fillByDate>
<items>
<item>
<supplier>Miloud Company</supplier>
<itemNo>SL35-721</itemNo>
<unitCost>17.97</unitCost>
<qty>12</qty>
</item>
<item>
<supplier>Spezi Company</supplier>
<itemNo>CP01-487</itemNo>
<unitCost>162.75</unitCost>
<qty>5</qty>
</item>
<item>
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</item>
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</item>
<item>
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</order>
</items>
</item>
'), SYSDATE)
<supplier>SOMAPHA Company</supplier>
<itemNo>ML32-42</itemNo>
<unitCost>12.25</unitCost>
<qty>5</qty>
<supplier>Al-Watania Company</supplier>
<itemNo>KP96-351</itemNo>
<unitCost>16.70</unitCost>
<qty>5</qty>
<supplier>Bouchta Company</supplier>
<itemNo>CT01-365</itemNo>
<unitCost>62.05</unitCost>
<qty>5</qty>
Inserting, Querying and Updating
► The
XML document can be retrieved in a query using
getClobVal()
► select
o.xmlOrder.getClobVal() from ORDERS o
WHERE
o.xmlOrder.existsNode('/order/items')= 1
► select
extract(o.xmlOrder,’/’) from ORDERS o
WHERE
o.xmlOrder.existsNode('/order/items')= 1
Hint
► In
order to display many lines of the XML
result in the sql*plus:
► set long 10000
► Set pagesize 10000
Inserting, Querying and Updating
► You
can even combine both types of access
into a single SQL query
SELECT orderNo, customerId,
extractValue(xmlOrder,
'/order/fillByDate') FillByDate,
date_entered FROM orders
Inserting, Querying and Updating
► The
XML document can be updated using
► update
orders SET xmlOrder =
updateXML(xmlOrder,
'/order/items/item[2]/qty/text()',10);
Creating XMLType Indices
►Indices
can be created on XMLType
columns
►These
indices can either be functionbased using extract() or existNodes().
Latter is better for bit-mapped indexes
Creating XMLType Indices
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CREATE INDEX FillBy_NDX ON ORDERS
(xmlOrder.extract('/order/fillByDate').
getStringVal());
CREATE BITMAP INDEX MultItems_NDX ON
ORDERS
(xmlOrder.existsNode('/order/items/
item/supplier'));
Creating Context Indexes
► Oracle
ConText indexes can be defined
for XMLTypes columns or tables
CREATE INDEX co_ctx_ndx ON
orders(xmlOrder) indextype is
ctxsys.context;
► Operation
be used
such as CONTAINS can then
The XMLType/XML DB APIs
► XMLType
Member Functions
► SYS_XMLGEN, SYS_XMLAGG and
DBMX_XMLGEN
► SQL/XML Functions
► PL/SQL DOM API (DBMS_XMLDOM)
► PL/SQL Parser API (DBMS_XML_PARSER)
► XSLT Processor (DBMS_XSL_ PROCESSOR)
► DBMS_XDBT (Context indexes)
► The XML DB Repository views
►XML
DB Repository
XML DB Repository
► It
is possible to have your cake and eat it
too
► You can store your document as a Native
XML Type in Oracle's XML DB repository,
which will preserve byte-by-byte document
fidelity and also shred it into SQL tables.
XML DB Repository
► When
your XML schema is registered, you
store your XML data in your database, by
simply inserting an XML document file using
SQL, PL/SQL, Java, FTP, HTTP, or WebDAV.
► Getting XML data out of your database can
be as simple as executing a SQL query or
reading a file using one of those Internetstandard protocols.
XML DB Repository Features
► Provides
access to XML content using a
foldering metaphor
► Includes ACLs (Access Control Lists) to
control secured access to XML data
► Access includes HTTP, WedDAV and FTP
► WebDAV provides directory-like access to
XML from any WebDAV-enabled device such
as Windows desktops
► FTP access is provided for XML application
development requiring file transfers
► Document versioning is also available
XML DB Repository
►There
are many advantages to
the XML DB repository, but it isn't
right for every application.
►Overhead
is involved in
maintaining the relationship
between the full document and
its shredded data.
XML DB Repository
► However,
the biggest problem comes with
schema evolution.
► That means you can't do most nontrivial
changes of either the database or the
document schema, without having to export
all the data and re-import it into the
database.
XML DB: Comming Soon
► In
the future, Oracle is looking at adding
several new capabilities:
► XQuery: which will be a language
specifically designed to query XML data
from a document perspective, rather than
the rows-and-tables perspective of SQL.
► (A prototype of XQuery language is
available for download on OTN.)
Summary
Oracle XML DB
► Oracle
XML DB
 Adds native support for the emerging XML
standards to the popular Oracle database
 Brings SQL and XML processing together
 introduces a number of innovations needed for
efficient storage and retrieval of XML.
XML-Type Summay
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XML can be stored one of two ways:
 An XMLType column in a relational table.
 An XML object in an XMLType table.
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Non Schema based XML is always stored as CLOB.
Schema based XML can be stored as a CLOB or as a
set of objects.
Relational and external data can be exposed as XML
using views.
The view can be a relational view containing a
column of XMLType or can be a XMLType View.
CLOB vs. Structured Storage
Feature
CLOB
Structured
Format
Unstructured
Structured
Storage
Whole document
Decomposed
Integrity
Original content
DOM Fidelity
Performance
Mediocre for DML
Excellent for DML
Space
Can be large
Less space
References
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1. Oracle 9i XML Database Developer's Guide: Appendix A – Installing
and Configuring XML DB.
(http://otn.oracle.com/tech/xml/doc.html)
2. Oracle 9i: XML API Reference.
(http://otn.oracle.com/tech/xml/doc.html)
3. W3C XML 1.0 Recommendation. (http://www.w3.org/TR/REC-xml)
4. W3C XML Schema Recommendation.
(http://www.w3.org/TR/xmlschema-1 and
http://www.w3.org/TR/xmlschema-2 )
5. Altova's XML Spy. (http://www.xmlspy.com)
6. Oracle 9i XML Database Developer's Guide: Appendix G – Example
Setup Scripts. At the beginning of this section, there is a script that you
can run to create a directory to contain your schemas and XML
documents as well as for getDocument() procedure to load these files
into XML DB (http://otn.oracle.com/tech/xml/doc.html)