xml schema part 1

Q5M1 - XML Dudy Fathan Ali S.Kom

XML SchemaQ5M1 - XML

Dudy Fathan Ali, S.Kom (DFA)2015

CEP - CCITFakultas Teknik Universitas Indonesia

Introducing XML Schema


An XML schema defines the list of elements and attributes that can be used in an XML document. An XML schema specifies the order in which the elements appear in the XML document, and their data types. Microsoft has developed the XML Schema Definition (XSD) language to define the schema of an XML document.

Advantages of XML Schema Created Using XSDs


Some of the advantages of creating an XML schema by using XSD are:

XSD provides control over the type of data that can be assigned to elements and attributes. XSD enables you to create your own data types. XSD enables you to specify restrictions on data. The syntax for defining an XSD is the same as the syntax used for XML documents. XML schema content models can be used to validate mixed content. XML schema is extensible.XML schema is self documenting.

Support for XML Schemas in Various Parsers


Parsers that provide support for XML schemas are:IBM XML4J: Validates XML documents against several types of XML schemas.MSXML 6.0: Enables loading of XML data from anonymous or untrusted sources in a secured manner.

Data Types in XML Schemas


In an XML schema created using XSD, every element must be associated with a data type.XSD provides the following list of predefined data types:

PrimitiveDerivedAtomicListUnion





Cannot be broken down into smaller units.

Can be primitive or derived.





Are derived data types that contain a set of values of atomic data types.

Elements referring to a list data type can contain a value only from that defined set.




PrimitiveDerivedAtomicListUnion Are derived from the atomic and list data

types.

Elements in XML Schemas


There are two types of elements, simple and complex that can be defined in a schema.Simple Element

A simple element does not contain any child elements or attributes.It contains only values, such as numbers, strings, and dates. You can specify restrictions on elements by defining a new simple data type from an existing data type using facet values.You can also associate an element with a simple data type.



Simple Element• prodid• productname• description• price• quantity



Complex ElementA complex element contains other elements, attributes, and mixed content.To declare a complex element, you need to first define a complex data type.After defining the complex data type, you can declare a complex element by associating this data type with the element.



Complex Element• productdata• product

Syntax for declaring simple element



<xsd:element name=“element-name" type="data type" min0ccurs="nonNegativeInteger“max0ccurs="nonNegativeInteger|unbounded“

/>

The name attribute specifies the name of the element declared.

The type attribute specifies the data type of the element declared.

minOccurs specifies the minimum number of times the element can occur.

maxOccurs specifies the maximum number of times the element can appear.



Simple element declaration code:

Syntax for declaring complex element



<xsd:complexType name="data type name">Content model declaration

</xsd:complexType>

The complexType element is used to declare a new complex data type.

The name attribute specifies the name of the new complex data type.

The Content model declaration contains the declaration for the elements and attributes that make up the content of the complex type.



Complex element declaration code:



Full XSD Schema

XML Namespace


In XML, a namespace is a virtual space that is assigned or recognized by a Uniform Resource Identifier (URI). A namespace is a string that uniquely identifies the elements and attributes from different schemas.A namespace is a unique identifier used to resolve conflicts between elements that have the same names.The following guidelines ensure the uniqueness of a URI:

Using a URI that is controlled by the developer.Using a relative URI.

XML Namespace


A namespace can be declared in an XSD document by using the xmlns keyword.The general form of the xmlns keyword is:xmlns:prefix="URI“

There are two types of namespace declarations:Default Declaration: Declares a default namespace for a document without specifying the prefix for a default namespace. Explicit Declaration: Enables xmlns keyword to associate a prefix with a namespace.

xmlns is the name of the attribute.

prefix is an optional namespace.


Terima KasihDudy Fathan Ali S.Kom

[email protected]

mailto:[email protected]

xml schema part 1

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