웹기술및응용. XML Schema 2018 년 2 학기. Instructor: Prof. Young-guk Ha Dept. of Computer Science & Engineering

Size: px

Start display at page:

Download "웹기술및응용. XML Schema 2018 년 2 학기. Instructor: Prof. Young-guk Ha Dept. of Computer Science & Engineering"

Justina Mosley
5 years ago
Views:

1 웹기술및응용 XML Schema 2018 년 2 학기 Instructor: Prof. Young-guk Ha Dept. of Computer Science & Engineering

2 Outline History Comparison with DTD Syntax Definitions and declaration Simple types Namespace Complex types Content models Secondary components 2

3 Birth of XML Schema XML-Data: Jan 1998 Basic concepts of XML Schema For W3C internal discussion only XDR (XML-Data Reduced): Jul 1998 Refines and subsets XML-Data down to manageable size Other Schema Languages DCD for XML (Document Content Description) DDML (Document Definition Markup Language) SOX (Schema for Object-oriented XML) XML Schema (W3C Recommendation) May 2001: XML Schema 1.0 Oct. 2004: XML Schema 1.0 2nd Edition Apr. 2012: XML Schema 1.1 W3C XSD Recommendation - Part 0: Primer - Part 1: Structures - Part 2: Data types XML Schema is also called XML Schema Definition Language (XSD) 3

4 Outline History Comparison with DTD Syntax Definitions and declaration Simple types Namespace Complex types Content models Secondary components 4

5 DTD vs. XML Schema 5

6 Outline History Comparison with DTD Syntax Definitions and declaration o Building blocks o Element & attribute declaration Simple types Namespace Complex types Content models Secondary components 6

7 Building Blocks Schema declaration Root of the document Namespace declarations Declarations Elements Attributes Type definitions Simple types for elements and attributes Complex types for elements 7

Declarations Element declaration decimal type := simpletype

maxoccurs := 0 ~ unbounded DTD Example) XML document with element

</product> <product> <name>bolt-002</name> </product> <product>

8 Declarations Element declaration decimal type := simpletype complextype Cardinality constraints - minoccurs := 0, 1, 2, - maxoccurs := 0 ~ unbounded DTD Example) XML document with element amount <product> <name>bolt-001</name> <amount>1000</amount> </product> <product> <name>bolt-002</name> </product> <product> <name>bolt-003</name> <amount>1000</amount> <amount>2000</amount> <amount>3000</amount> </product> 8

attribute partnum <quantity partnum= Bolt-001 unit= ea value= 1000 />

9 Declarations (cont d) Attribute declaration type := simpletype use := required optional prohibited DTD #REQUIRED > Example) XML document with attribute partnum <quantity partnum= Bolt-001 unit= ea value= 1000 /> <quantity unit= ea value= 2000 partnum= Bolt-002 /> <quantity unit= ea value= 3000 /> invalid 9

10 Outline History Comparison with DTD Syntax Definitions and declaration Simple types o Built-in, user-derived types o List, union types o Facets Namespace Complex types Content models Secondary components 10

11 Simple Types Built-in types Derived from anysimpletype o Primitive types Types in their own right Not defined in terms of other data-types o Derived types List or restriction of existing primitive types User-defined types Defined by the author of the schema and particular to the schema o List, union, and restriction are allowed for user-defined simple types o Extension is NOT allowed for simple types Note that complex types can be derived by either extension or restriction 11

12 Simple Types: Built-in Datatype Hierarchy DTD 호환성 12

13 Simple Types: Primitive Types double 13

14 Simple Types: Derived Types -128~127 14

15 Simple Types: User-Derived Types User-derived types Only restriction of simple base type is allowed o Extension is NOT allowed o E.g., expansion of range or addition of attributes is not allowed Example) Defining myinteger of range 1000~

16 Facets (1/2) length Determines the length of data type minlength o For string, it means the number of characters it contains o For binary data such as base64binary, it means the number of octets Sets the minimum length of the data type Less than or equal to maxlength maxlength Sets the maximum length of the data type pattern Specifies a regular expression which the element content should match enumeration Contains a set of values that element have to choose one 16

17 Facets (2/2) whitespace Controls how the processor should treat whitespace chars o preserve (default), replace, or collapse maxinclusive, maxexclusive Sets an upper bound for values using the data type mininclusive, minexclusive Sets an lower bound for values using the data type mininclusive value maxinclusive minexclusive < value < maxexclusive precision, scale precision determines the maximum number of digits the data type may have (including comma. ) scale sets the maximum number of digits appearing in the fractional part of a decimal based data type 17

18 Facets Examples /> 10 chars long, e.g., e.g., one of 10, 20, or part Code precision value= 6 /> scale value= 1 /> e.g., , , , e.g., 123-AB, 327-XY, 617-ST, 18

19 Simple Types: List types List types Derived from existing primitive types, NOT from list or complex types Built-in: NMTOKENS, IDREFS, ENTITIES Using whitespace as a delimiter E.g.) User-defined list type <element name= listofinteger type= listofintegertype > XML Schema of listofintegertype XML Document 19

20 Simple Types: Union types Union types Enables an element or attribute value to be one or more instances of one type drawn from the union of multiple primitive and list types E.g.) <xsd:element name= zips type= zipunion > XML Schema of zipunion type XML Document 20

21 Outline History Comparison with DTD Syntax Definitions and declaration Simple types Namespace Complex types Content models Secondary components 21

22 Namespace XML Namespace W3C Recommendation o First edition on Jan o Currently, v1.0 3 rd Ed. (Dec. 2009) and v1.1 2 nd Ed. (Aug. 2006) Resolves name conflict between elements or attributes in XML documents o Qualified names of elements or attributes are required to be globally unique and persistent o Namespace can be used in XML docs and XSD docs as well Identified by URI (URL or URN) o However, actually identified by a short prefix (URI is quite long) o Note that the URL needs NOT to point to an actual document or location Default namespace o Unprefixed elements or attributes are associated with the default namespace of themselves or parent element s (block scope) * URI: Uniform Resource Identifier (= URL + URN) * URL: Uniform Resource Locator * URN: Uniform Resource Name 22

23 Namespace (cont d) 세개의 <title> element 가서로다른의미로사용되고있음 ( 또한같은 scope 내에동음이의 element 가사용될수도있음 ) 또한타 Markup 언어의 <title> element 와도구별할필요가있음 ( 예 : XHTML 의 <title>) 각각의 <title> element 가식별되지않는다면 well-formed 이지만 valid 하지않은 XML 문서로해석될가능성이있음 23

24 Namespace (cont d) Namespace declaration <element xmlns:edi= > Prefix Namespace URI Default namespace declaration <element xmlns= > * No prefix is defined for default namespace E.g.) <schema xmlns= Target namespace declaration (XSD docs only) <element targetnamespace= > 24

25 Namespace (cont d) 네임스페이스사용예 Namespace prefix = edi Namespace URI = <edi:x xmlns:edi= > <edi:price edi:units= Euro >32.18</edi:/price> </edi:x> 디폴트네임스페이스를사용하는경우 <x xmlns= > <price unit= Euro >32.18</price> </x> 25

26 Namespace (cont d) Well-known namespaces xsd= xsi= xhtml= xslt= wsdl= soapenv= soaprpc= xmldsig= xmlenc= 26

27 Namespace (cont d) 네임스페이스의적용범위 XML 문서는하나이상의네임스페이스를가질수있음 네임스페이스는네임스페이스가선언된 element 와그 element 의내부에 nested 된모든 element 및 attribute 들에적용됨 (block scope) 27

28 Namespace in XML Schema Target Namespace Using XML Schema, we can create new elements and attributes, and keep them in a specific namespace This particular namespace is target namespace where the newly created elements and attributes will reside During validation, an XML parser verifies whether the elements and attributes used in the document exist in the declared target namespace / 28

Namespace in XML Schema (cont d) <schema xmlns="http://www.w3.org/2001/xmlschema" xmlns:po="http://www.example.

29 Namespace in XML Schema (cont d) <schema xmlns=" xmlns:po=" targetnamespace=" <complextype name="usaddress"> <sequence> <element name="name" type="string"/> <element name="street" type="string"/> </sequence> </complextype> <complextype name="purchaseordertype"> <sequence> <element name="shipto" type="po:usaddress"/> <element name="billto" type="po:usaddress"/> </sequence> </complextype>... <element name="purchaseorder" type="po:purchaseordertype"/> </schema> 29

Namespace in XML Schema (cont d) Valid XML document example <purchaseorder xmlns= http://www.example.com/po.

30 Namespace in XML Schema (cont d) Valid XML document example <purchaseorder xmlns= > <shipto> <name>micheal</name> <street>main street</street> </shipto> <billto> <name>tom</name> <street>fremont street</street> </billto>... </purchaseorder> 30

Namespace in XML Schema (cont d) Including XML Schema definitions from external documents <schema xmlns="http://www.w3.

xsd > <element name="purchaseorder" type="po:purchaseordertype"/> </schema> http://www.example.com/po1.

31 Namespace in XML Schema (cont d) Including XML Schema definitions from external documents <schema xmlns=" xmlns:po=" targetnamespace=" > <include schemalocation= > <element name="purchaseorder" type="po:purchaseordertype"/> </schema> * 동일 target namespace <schema xmlns=" targetnamespace=" > <complextype name="purchaseordertype"> </complextype> </schema> 31

32 Outline History Comparison with DTD Syntax Definitions and declaration Simple types Namespace Complex types o Extension, restriction o Adding attribute o Global & local element Content models Secondary components 32

33 Complex Types Features of complex types Carrying attributes and elements o I.e., contains other types (simple or complex) Can be derived by both restriction and extension o Cf., only restriction allowed for simple types Various and flexible content models o Any, empty, element-only, mixed o Model groups: sequence, all, choice o Cardinality constraints: minoccurs, maxoccurs o Combinations of the above 33

Complex Types: Complex Type Definition Model group (can be nested) Elements (simple or complex types) Attributes <schema xmlns="http://www.w3.org/2001/xmlschema" xmlns:po="http://www.example.

34 Complex Types: Complex Type Definition Model group (can be nested) Elements (simple or complex types) Attributes <schema xmlns=" xmlns:po=" targetnamespace=" <element name="purchaseorder" type="po:purchaseordertype"/> <complextype name="purchaseordertype"> <sequence> <element name="shipto" type="po:usaddress"/> <element name="billto" type="po:usaddress"/> <element ref="po:comment" minoccurs="0 maxoccurs= 10 /> </sequence> <attribute name="orderdate" type="date"/> </complextype> <complextype name="usaddress"> <sequence> <element name="name" type="string"/> <element name="street" type="string"/> </sequence> </complextype> Specific cardinality 34

35 Complex Types: Attribute Declaration Only simple types can be used for attribute types Examples <attribute name= orderdate /> <attribute name= orderdate type= date /> <attribute name= orderdate type= date use= required fixed= /> <attribute name= orderdate type= date use= optional default= /> <attribute name= orderdate type= date use= prohibited /> * prohibited: usually used to restrict the base element 35

Complex Types: Extension & Restriction (1) Deriving types by extension Base type Derived type Extension from a complex type o Adding new elements or attributes to a base type Extension from a simple

36 Complex Types: Extension & Restriction (1) Deriving types by extension Base type Derived type Extension from a complex type o Adding new elements or attributes to a base type Extension from a simple type o Adding new attributes to a base type o Expanding range, length, Deriving types by restriction Base type Derived type Restriction from a complex type o Limited cardinality of element, use of attributes, o Prohibiting attributes (e.g., use= prohibited ) Restriction from a simple type o Limiting range, length, <complextype> <complexcontent> <simplecontent> <restriction> <extension> <restriction> <extension> [ Derivation of Complex Types ] 36

37 Complex Types: Extension & Restriction (2) Limited cardinality Additional elements [ Extension from a simple type by adding an attribute ] [ Extension and restriction from a complex type ] 37

38 Complex Types: Scope of Elements Global elements Direct children of the schema element Can be referenced using attribute ref Local elements Child elements of another element Local elements with the same name can be declared in different scopes Global Element Local Element 38

39 Outline History Comparison with DTD Syntax Definitions and declaration Simple types Namespace Complex types Content models o Any, empty, mixed o Sequence, choice, all o minoccurs, maxoccurs Secondary components 39

40 Basic Content Models Any type Default content model when you declare an element in XML Schema o <element name= anything /> == <element name= anything type= anytype /> Can contain any contents (completely unconstrained) o E.g., string, integer, elements,, or mixture of them Empty content Can carry attributes, but prevent any content appearing as text or child elements o <element name= empty xsi:nil= true /> xmlns:xsi= Mixed content and element only Mixture of text contents and elements o <xsd:element name="letterbody"> <xsd:complextype mixed="true">... Default: mixed= false (element-only) 40

41 Mixed Content Model [ Valid XML Document ] [ XML Schema ] 41

42 Model Groups sequence group Only allows the specified order in an instance choice group Allows only one of its children to appear in an instance all group Unordered subset of individual elements o Children may appear in any order o Children may appear once or not (no more than once) o Children must all be individual elements (no groups) o Children are restricted to contain local elements or refs to top-level elements declarations only Must appear o as the sole child o at the top of content model 42

43 Cardinality Constraints minoccurs Value: nonnegative integer (Default = 1) maxoccurs Value: nonnegative integer or unbounded (Default = 1) Examples <element name= e1 /> == <element name= e1 minoccurs= 1 maxoccurs= 1 /> DTD: <!ELEMENT e0 (e1)> <element name= e1 minoccurs= 0 maxoccurs= 1 /> DTD: <!ELEMENT e0 (e1?)> <element name= e1 minoccurs= 0 maxoccurs= unbounded /> DTD: <!ELEMENT e0 (e1*)> <element name= e1 minoccurs= 1 maxoccurs= unbounded /> DTD: <!ELEMENT e0 (e1+)> <element name= e1 minoccurs= 3 maxoccurs= 10 /> can not be described with DTD 43

44 Content Model Example: Sequence & Choice <xsd:complextype name="purchaseordertype"> <xsd:sequence> <xsd:choice> <xsd:sequence> <xsd:element name="shipto" type="usaddress"/> <xsd:element name="billto" type="usaddress"/> </xsd:sequence> <xsd:element name="singleusaddress" type="usaddress"/> </xsd:choice> <xsd:element ref="comment" minoccurs="0"/> <xsd:element name="items" type="items"/> </xsd:sequence> <xsd:attribute name="orderdate" type="xsd:date"/> </xsd:complextype> 44

45 Content Model Example: Sequence & Choice <PurchaseOrder orderdate= > <shipto>... </shipto> <billto>... </billto> <comment>... </comment> <items>... </items> </PurchaseOrder> [ Valid XML documents ] <PurchaseOrder orderdate= > <singleusaddress>... </singleusaddress> <comment>... </comment> <items>... </items> </PurchaseOrder> <PurchaseOrder orderdate= > <singleusaddress>... </singleusaddress> <items>... </items> </PurchaseOrder> 45

46 Content Model Example: All <xsd:complextype name="purchaseordertype"> <xsd:all> <xsd:element name="shipto" type="usaddress"/> <xsd:element name="billto" type="usaddress"/> <xsd:element ref="comment" minoccurs="0"/> <xsd:element name="items" type="items"/> </xsd:all> <xsd:attribute name="orderdate" type="xsd:date"/> </xsd:complextype> *** Illegal: used in a sequence group *** <xsd:complextype name="purchaseordertype"> <xsd:sequence> <xsd:all> <xsd:element name="shipto" type="usaddress"/> <xsd:element name="billto" type="usaddress"/> <xsd:element name="items" type="items"/> </xsd:all> <xsd:sequence> <xsd:element ref="comment" minoccurs="0" maxoccurs="unbounded"/> </xsd:sequence> </xsd:sequence> <xsd:attribute name="orderdate" type="xsd:date"/> </xsd:complextype> 46

47 Outline History Comparison with DTD Syntax Definitions and declaration Simple types Namespace Complex types Content models Secondary components o Attribute groups o Annotation o Redefinition o Abstract element o Null element 47

indicate the language of the information <attributegroup name="myattrgroup"> <attribute... />.

48 Attribute Groups & Annotation Attribute groups Improves readability of schemas and facilitates updating schemas Must appear at the end of complex type definitions Annotation Annotating schemas for benefit of human readers and applications as well Use xml:lang attribute to indicate the language of the information <attributegroup name="myattrgroup"> <attribute... />... </attributegroup> <complextype name="myelement">... <attributegroup ref="myattrgroup"/> </complextype> <annotation> <documentation xml:lang= en > Some documentation </documentation> </annotation> 48

49 Redefinition To provide some support for evolution or versioning of XML schema files The redefine mechanism enables you to redefine simple and complex types, groups, and attribute groups that are obtained from external schema files (i.e., restriction or extension from the original version) o Cf., the include mechanism enables you to use externally created schema components as-is (i.e., without any modification) Redefinition requires the external components to be in the same target namespace as the redefined schema 49

Redefinition Example v1.xsd : targetnamespace="http://mycom.

name="forename" minoccurs="0 maxoccurs="unbounded"/> </sequence> </complextype> v2.

50 Redefinition Example v1.xsd : targetnamespace=" <complextype name="personname"> <sequence> <element name="title" minoccurs="0"/> <element name="forename" minoccurs="0 maxoccurs="unbounded"/> </sequence> </complextype> v2.xsd : targetnamespace=" xmlns:p=" <redefine schemalocation= v1.xsd"> <complextype name="personname"> <complexcontent> <extension base= p:personname"> <sequence> <element name="generation" minoccurs="0"/> </sequence> </extension> </complexcontent> </complextype> </redefine> <element name="author" type="personname"/> 50

Substitution Groups Substitution groups allow elements to be substituted for other elements Head element o a particular named element to be substituted o E.g., ipo:comment Substitutable elements o E.

substitutiongroup="ipo:comment"/> <element name="customercomment" type="string" substitutiongroup="ipo:comment"/> <element name="item" minoccurs="0" maxoccurs="unbounded"> <complextype> <sequence>

51 Substitution Groups Substitution groups allow elements to be substituted for other elements Head element o a particular named element to be substituted o E.g., ipo:comment Substitutable elements o E.g., shipcomment, customercomment Both types of elements must be declared as global elements <element name="ipo:comment" type="string"/> <element name="shipcomment" type="string" substitutiongroup="ipo:comment"/> <element name="customercomment" type="string" substitutiongroup="ipo:comment"/> <element name="item" minoccurs="0" maxoccurs="unbounded"> <complextype> <sequence> <element name="productname" type="string"/> <element ref="ipo:comment" maxoccurs= unbounded"/> <element name="shipdate" type="date" minoccurs="0"/> </sequence> </complextype> </element> <item partnum="833-aa"> <productname>lapis necklace</productname> <ipo:comment>order #1</ipo:comment> <ipo:shipcomment>use gold wrap</ipo:shipcomment> <ipo:customercomment>want ASAP!</ipo:customerComment> <shipdate> </shipdate> </item> 51

Abstract Elements and Abstract Types Abstract elements can NOT be used in an instance document To make a substitutable element MUST appear in the instance document o From the previous example

52 Abstract Elements and Abstract Types Abstract elements can NOT be used in an instance document To make a substitutable element MUST appear in the instance document o From the previous example <element name= ipo:comment" type="string abstract="true"/> Abstract type elements Must be used with a specific derived type in instance documents o E.g., <transport> element  <complextype name="vehicle" abstract="true"/> <complextype name="car"> <complexcontent> <extension base="ns:vehicle"/> </complexcontent> </complextype> <complextype name="plane"> <complexcontent> <extension base="ns:vehicle"/> </complexcontent> </complextype> <element name="transport" type="ns:vehicle"/> <transport/> <transport xsi:type="ns:car"/> Schema invalid Schema valid * xsi=" 52

53 Null Element An element that can has a null value as its content Meaning of null value o Unknown o Not applicable o The element may be absent XML has no actual null value that appears as element content o E.g.) <shipdate>null</shipdate> null string value Using attribute xsi:nil In the schema: nillable= true In the document: xsi:nil= true /> 53

54 References XML Schema 1.0 (2 nd Ed) Part 0: Primer XML Schema 1.0 (2 nd Ed) Part 1: Structures XML Schema 1.0 (2 nd Ed) Part 2: Data types Namespaces 1.0 (3 rd Ed) in XML 54

XML DTDs and Namespaces. CS174 Chris Pollett Oct 3, 2007.

XML DTDs and Namespaces. CS174 Chris Pollett Oct 3, 2007. XML DTDs and Namespaces CS174 Chris Pollett Oct 3, 2007. Outline Internal versus External DTDs Namespaces XML Schemas Internal versus External DTDs There are two ways to associate a DTD with an XML document: