Accessing DataUsing XML

CHAPTER NINE

Matakuliah : T0063 – Pemrograman VisualTahun : 2009

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Introduction

• The eXtensible Markup Language (XML) is a language used to represent data in a form that does not rely on any particular proprietary technology.

• XML Schema provides a way of defining and validating XML documents.

• eXtensible Stylesheet Language (XSL) and eXtensible Stylesheet Language Transforms(XSLT) is another useful technology associated with XML.

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Introduction (cont.)

• This capability enables you to take a single XML document and transform it into a variety of different versions for specific uses.

• A number of classes within Visual Basic .NET provide methods that work directly with XML.

• Microsoft’s .NET initiative uses XML as its foundation data technology.

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Objectives

• Understand what XML is and how it is used within business-to-business transactions.

• Understand XML Schemas and XSL Transforms and how they are used within the context of XML.

• Read and process data that are stored in an XML document.

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Objectives (cont.)

• Read data from a relational database and transform them into their equivalent XML.

• Transform one XML document into a new XML document using an XSLT document.

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9.1 An XML Primer• What is XML?

– XML provides a technology-neutral way to represent data.

– XML is rapidly becoming the data format “standard” for the exchange of data on the Internet.

– Data content and data presentation are separate.– Data represent what is called a tree.

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9.1 An XML Primer (cont.)• XML Syntax

– The language is case sensitive.– There is one and only one root node.– All elements have a start tag and an end tag.– Tags must be nested correctly.– Attributes must be quoted.

• An XML document is well formed if you follow the above rules.

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9.1 An XML Primer (cont.)

– Namespaces• A namespace defines a point of reference.

– Change the element tag by adding a prefix and a colon to the tag.

– Ex. <furn:table> and <tax:table>.• Can differentiate two tags within the same

document.• Syntax: xmlns:name = “uri”• The uri (Uniform Resource Identifier) is a unique

identifier.

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9.1 An XML Primer (cont.)

– Document Prolog• Indicates that the document is XML as well

as other things such as document type, entity definitions and other processing instructions.

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9.1 An XML Primer (cont.)

• XML Schemas– Rules that define legal elements, tags, and content.– Used to determine the validity of a document.– Industry specific XML schemas are being

developed.

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9.1 An XML Primer (cont.)

• Styling XML– Extensible Stylesheet Language Transforms

(XSLT) provide a way to transform one XML document to another XML document.

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9.2 Creating XML Documents and XML Schemas Using Visual Basic .NET

• Creating an XML Schema– Add an XML Schema to a project by selecting Add

New Item from the File menu.– Use tools from the Toolbox to create the schema.– Save the Schema definition.

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9.2 Creating XML Documents and XML Schemas Using Visual Basic .NET

(cont.)• Creating an XML Document

– Complete the examples listed below in your textbook:• Example 9.1 Using Simple and Complex Data

Types in XML Schemas. • Example 9.2 Creating Nested Relationships in

an XML Schema.• Example 9.3 Creating Tables with

Relationships in an XML Schema.• Example 9.4 Transforming XML using XSLT.

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9.3 Using ADO.NET with XML

• ADO.NET provides a number of useful classes and methods to work directly with XML documents.– Data are already in XML form.

• This section provides a number of examples that demonstrate XML capabilities of the ADO.NET framework.

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9.3 Using ADO.NET with XML (cont.)

• Complete the following examples listed below in your textbook:– Example 9.5 Processing an XML Document.– Example 9.6 Converting Relational DB Data into XML.– Example 9.7 Using XML and XSLT to Transform Data

from a Relational Database.