ACG 4401

XML SchemasXML NamespacesXMLink

+The XML Foundation

Many participants – an extended family! XML Instance documents – carry data in context

Each must be parsed into its component parts XML Schemas – define the rules a class of documents

must follow Can be used to validate documents & contents

XSLT – provide processing instructions Can be used to process XML documents

Namespaces – qualify elements & attributes Differentiate & associate them with a URI

XPath … XLink … XQuery … XML Processors are not designed equally!

+ XML Schema Language

Language used to create Schema Documents

Schema Used to define the structure and content of Instance documents

Well-formatted XML document Definition: “provide a means for defining the structure, content and

semantics of XML documents.” (W3C)

Defines structure and contents of Instance Document Similar to an ER-Diagram for databases Defines Each Element and Attribute Its Structure

Includes Business Rules Cardinalities

Used to Validate Instance Document Means Instance Document conforms to Schema Rules

+XML Schema

.xsd extension But won’t open in IE so use .xml if using that browser

Defines each attribute and extension

+Vocabularies & Schemas

XBRL & UBL are vocabularies XBRL for Financial Reporting UBL for Business Documents

Vocabularies are designed using Agreed upon element names Agreed upon element types Agreed upon element sequence/structure

Defined by Schemas

6+Namespaces

Each XML Vocabulary is associated with a unique NameSpace A unique identifier (think, primary key) Universal Resource Identifier

Local Name (e.g. TeeTimeResevations.xml) URL (http://www……)

Used to prevent naming collisions (more later)

+ Vocabularies and Namespaces

Namespace

A Unique Identifier

Unique Prefix refers to URI

Points to where information in an XML Document can be found. (URI)

Attribute of Root Element

Definition: “XML namespace: In XML, a namespace is a collection of names, identified by a URI reference, that are used in XML documents as element types and attribute names. In order for XML documents to be able to use elements and attributes that have the same name but come from different sources, there must be a way to differentiate between the markup elements that come from the different sources.” (Webopeida) (Technical Information from W3.org)

Used to preclude naming collisions

Method for distinguishing between the same element name for different elements

<inv:id>10001</inv:id> ...

<employee:id>18897</employee:id>

8+Types of Elements Simple

contain only data

<SalesOrderID>98765</SalesOrderID>

Complex

contain other elements (i.e. Root & Parent)

<PartyName>

<Name>Bicycles Online, Inc.</Name></PartyName>

contain attributes

<PriceAmount currencyID="USD">730.55</PriceAmount>

+Simple Element Definition

Declare Name

Declare Type

<xs:element name=“ID” type=“xs:string”/>

Type= Defines the data type:

string Integer date decimal other types

+Complex Element (Parent)

Declares Name

Declares type

Declares Structure

11+Complex Element (Parent) xml

<xs:element name="Party">

<xs:complexType>

<xs:sequence>

<xs:element ref="PartyName" minOccurs="1" maxOccurs="1"/>

<xs:element ref="PostalAddress" minOccurs="1" maxOccurs="1"/>

<xs:element ref="Contact" minOccurs="0" maxOccurs="1"/>

</xs:sequence>

</xs:complexType>

</xs:element>

+Complex Element (attribute)

Declare Name

Declare Type

Define element and attribute(s)

13+Complex (Attribute) xml

<xs:element name="PriceAmount">

<xs:complexType>

<xs:simpleContent>

<xs:extension base="xs:decimal">

<xs:attribute name="currencyID" type="xs:string”use="required"/>

</xs:extension>

</xs:simpleContent>

</xs:complexType>

</xs:element>

+Create a Schema from a non-vocabulary instance document

Identify types of elements Simple Complex – Parent Complex – Attribute

Create Prolog

Create Root element

Work down from 1st element to last

15+Root Element

Root element is used to declare namespace(s)

<xs:schema xmlns:xs=“http://www.w3.org/2001/XMLSchema”>

xs: = namespace prefix

xmlns:xs defines prefix to use for namespace

“http:www.w3.org/2001/XMLSchema” location of Namespace, where the dictionary is

Prefix is used before each tag xs:tagname

+

Creating Schema from Instance DocumentPizzaOrders

16

17+Identify Element Types

PizzaOrder.xml

+UBL Schemas

Schemas for each document type

Common Basic Components Defines Simple Elements Defines Complex (attribute) Elements Prefix: cbc (Namespace prefix)

Common Aggregate Components Defines Complex (Parent) Elements Prefix: cac (Namespace prefix)

+Creating UBL Document Schemas

1. Declare NameSpaces and qualifiers

2. Import necessary Schemas

3. Define Root Element

1. Reference Reusable data components

2. Declare Cardinalities

+Declaring a Namespace (in the UBL instance document)

<Catalogue xmlns="UBLCatalogueDocument"

xmlns:cbc="UBLCommonBasicComponents"

xmlns:cac="UBLCommonAggregateComponents">

Since UBLCatalogueDocument does NOT have a prefix any element in the instance document without a prefix relates to this namespace.

UBL Catalogue Instance with namespaces

+1. UBL Namespace Declaration in Root Element

<?xml version="1.0" encoding="UTF-8"?>

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"

targetNamespace="UBLCatalogueDocument"

xmlns="UBLCatalogueDocument"

xmlns:cbc="UBLCommonBasicComponents"

xmlns:cac="UBLCommonAggregateComponents"

elementFormDefault="qualified"

attributeFormDefault="unqualified">

+Namespace Clarification

targetNamespace="UBLCatalogueDocument“ The schema being created/used is applied to the

UBLCatalogueDocument namespace

elementFormDefault="qualified“ Element names will use a namespace prefix

CAC: CBC:

attributeFormDefault="unqualified“ Attribute names will not use a namespace prefix

+2. UBL Import

<xs:import namespace="UBLCommonBasicComponents"

schemaLocation="http://www.buec.udel.edu/whitec/UBLCommonBasicComponents/UBLCommonBasicComponentsSchema.xsd"/>

<xs:import namespace="UBLCommonAggregateComponents"

schemaLocation="http://www.buec.udel.edu/whitec/UBLCommonAggregateComponents/UBLCommonAggregateComponentsSchema.xsd"/>

+3. UBL Root Element (Catalogue)

<xs:element name="Catalogue">

<xs:complexType>

<xs:sequence>

<xs:element ref="cbc:ID" minOccurs="1" maxOccurs="1"/>

<xs:element ref="cbc:Name" minOccurs="1" maxOccurs="1"/>

<xs:element ref="cbc:IssueDate" minOccurs="1" maxOccurs="1"/>

<xs:element ref="cac:ProviderParty" minOccurs="1" maxOccurs="1"/>

<xs:element ref="cac:ReceiverParty" minOccurs="1" maxOccurs="1"/>

<xs:element ref="cac:CatalogueLine" minOccurs=”1” maxOccurs="unbounded"/>

</xs:sequence>

</xs:complexType>

</xs:element>

Put it all together: The Entire Schema

+Validating XML

Ensure that Instance Document Follows business rules Data types are correct Data is properly sequenced

+XML Linking Language

XLink Uses attributes to describe relationships between

elements Simple: HTML type links Extended: More complex Relationship links

27+Simple links

Unidirectional and always Outbound

Link to list of approved Vendor

<InventoryItem xlink:type”simple” xlink:href=“http://….”/>

28+Extended Links

Attributes: xlink:type=“extended”

Used in Parent element Xlink:type=“locator”

Remote resource In Child element

Xlink:href=“http://….” In Child Element