ACG 5405
XML Schemas
XML Namespaces
XMLink
The XML Foundation
 Many participants – an extended family!
 XML 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 Languages - Schema
 Instance Document
 Elements (tag sets) meta-data about data
 Schema
 Well-formatted XML document
 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
 Defines each attribute and extension
 Root element is a namespace
 <xs:schema xmlns:xs=“http:www.w3.org/2001/XMLSchema”>
 Define an Element:



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Simple
 contain only data
Complex
contain other elements (i.e. Root & Parent)
contain attributes
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
<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)
 <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 for
Conceirge Instance
 Identify types of elements



Simple
Complex – Parent
Complex – Attribute
 Create Prolog
 Create Root element
 Work down from 1st element to last
Step 1
<ServiceRequest>
<Request>
<ID>1</ID>
<ApartmentNumber>1004</ApartmentNu
mber>
<TenantName>
<LastName>Hornik</LastName>
<FirstName>Steven</FirstName>
</TenantName>
<ServiceName>Dry
Cleaning</ServiceName>
<ServiceDate>2009-06-23</ServiceDate>
<ServiceTime>06:45 PM</ServiceTime>
</Request>
</ServiceRequest>
 Complex (Parent) Types:



ServiceRequest
Request
TenantName
 Simple Types:







ID
ApartmentNumber
LastName
FirstName
ServiceName
ServiceDate
ServiceTime
Step 2 and 3 (Prolog and
Root)
<?xml version=“1.0” encoding=“UTF-8”?>
<xs:schema
xmlns:xs=http://www.w3.org/2001/XMLSchema>
...
</xs:schema>
Step 4 – Build Schema
<xs:element name=“ServiceRequest">
<xs:complexType>
<xs:sequence>
<xs:element name=“Request“ minOccurs=“1” maxOccurs=“unbounded”>
<xs:complexType>
<xs:sequence>
<xs:element name=“ID” type=“xs:string”/>
<xs:element name=“ApartmentNumber” type=“xs:decimal”/>
<xs:element name=“TenantName“ minOccurs=“1”
maxOccurs=“1”>
<xs:complexType>
<xs:sequence>
<xs:element name=“LastName” type=“xs:string”/>
<xs:element name=“FirstName” type=“xs:string”/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name=“ServiceName” type=“xs:string”/>
<xs:element name=“ServiceDate” type=“xs:date”/>
<xs:element name=“ServiceTime” type=“xs:date”/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
UBL Schemas
 Schemas for each document type &
 Common Basic Components


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Defines Simple Elements
Defines Complex (attribute) Elements
Prefix: cbc
 Common Aggregate Components


Defines Complex (Parent) Elements
Prefix: cac
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
Vocabularies and Namespaces
 Namespace
A Unique Identifier
 Unique Prefix refers to URI
 Points to where information in an XML Document can be
found. (URI)
 Attributes of Root Element
 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>

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.
Creating UBL Document
Schemas
 Declare NameSpaces and qualifiers
 Import necessary Schemas
 Define Root Element


Reference Reusable data components
Declare Cardinalities
UBL Namespace Declaration
<?xml version="1.0" encoding="UTF-8"?>
<!-- Simplified UBL Catalogue schema: SkipWhite.com, May 2008 -->
<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
UBL Import
<xs:import namespace="UBLCommonBasicComponents"
schemaLocation="http://www.buec.udel.edu/whitec/UBL
CommonBasicComponents/UBLCommonBasicCompone
ntsSchema.xsd"/>
<xs:import
namespace="UBLCommonAggregateComponents"
schemaLocation="http://www.buec.udel.edu/whitec/UBL
CommonAggregateComponents/UBLCommonAggregate
ComponentsSchema.xsd"/>
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