Petros KAVASSALIS

1

Enterprise IT[Πληροφοριακές Τεχνολογίες της Επιχείρησης]

Lecture 4 & 5: XML Overview

Univ. of the Aegean Financial and Management Engineering Dpt

Petros KAVASSALIS<[email protected]>

<[email protected]> 2

What you will learn in this course

A set of fundamental concepts for understanding basic Enterprise Information Technologies Enterprise Software Applications Enterprise Architecture Integration (EAI)

Best practices and techniques for building and migrating to a service-oriented enterprise

Strategies for integrating applications using standard technologies XML Web Services

Familiarization with concepts such as: Interoperability e-business e-government 2.0


Communication tools

e-mail: [email protected] Course web site: see FME web site


Students evaluation

Class Participation (20%)

+ Assignments (20%)

+ Final Exam (650%)

First go to http://www.w3schools.com/xml/default.asp


http://www.w3schools.com/xml/default.asp

XML in a nutshell

XML: Extensible Markup Language XML Working Group at W3C (please visit!)

Used for the definition of methods of storing, processing and managing information (texts) in electronic form Device independent System independent

Used to represent business transactions within and outside the enterprise and mediate communication between systems that support transactions Example: purchase orders, invoices, shipping, bills of lading, warehousing

information delivery etc Used to standardize the process by which enterprise applications

exchange message in the context of a transaction (within the enterprise or between trading partners)


Markup etc.

Markup Describe annotations or special marks (codes) inserted into electronic texts to govern

text formatting, processing, printing etc. Make explicit the representation of text

Markup language A set of conventions put together for encoding texts

o What markup?o What is required?o What does it mean?o How can it be distinguished from text?

Meta-language Provides a way of formally describing a language, i.e. a markup language XML: no predetermined tags XML: Descriptive markup (the mark-up annotations simply categorize parts of the

document)


Re-usability

A language for creating other languages! One uses XML to design his (her) own custom markup language (XMP

application) The, he(she) uses this custom language to format documents

A tag identifies (characterizes) data, data in that way become available for other tasks Labeled information that can be re-used

Sister technology: XML Schemas Defines the custom markup language one creates with XML

o Specifies tags to use in a documento Tags and attributes these tags can contain


XML: Why do we need it? [from S. Madnick Course at MIT]


XML: Elements, Attributes and Values

http://www.w3schools.com/xml/default.asp <?xml version="1.0"?> <note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body> </note> http://www.w3schools.com/xml/xml_tree.asp




http://www.w3schools.com/xml/xml_tree.asp

http://www.w3schools.com/xml/xml_tree.asp

Note: [Reference for the following examples]

http://elizabethcastro.com/xml/examples/index.html#ch1


http://elizabethcastro.com/xml/examples/index.html

XML: Declaring the version, root element and other rules

<?xml version="1.0" ?> <endangered_species />

Closing tags are required Case matters Values must enclosed in quotations


XML: Nesting elements <inner>

<?xml version="1.0" ?> <endangered_species>

<animal><name>Tiger</name><threat>poachers</threat><weight>500 pounds</weight>

</animal> </endangered_species> Important: The elements in an XML document form a document tree. The tree starts at the

root and branches to the lowest level of the tree. An element nested with another is referred to as “child element” (or, inversely, “parent element”)

<root> <child> <subchild>.....</subchild> </child></root>


animal: 3 child elements

XML: Attributes


<animal> <name language="English">Tiger</name> <name language="Latin">panthera tigris</name> <threat>poachers</threat> <weight>500 pounds</weight> </animal> </endangered_species>


XML: Empty Elements


<animal> <name language="English">Tiger</name> <name language="Latin">panthera tigris</name> <threat>poachers</threat> <weight>500 pounds</weight> <source sectionid="120" newspaperid="21" /> <picture filename="tiger.jpg" x="200" y="197" /> </animal> </endangered_species>


XML: Writing comments


<animal> <name language="English">Tiger</name> <name language="Latin">panthera tigris</name> <threat>poachers</threat> <weight>500 pounds</weight>



<source sectionid="120" newspaperid="21" /> <picture filename="tiger.jpg" x="200" y="197" /> </animal></endangered_species>


XML: Special Symbols(&amp, &lt, &gt, &quot, &apos)


<animal> <name language="English">Tiger</name> <name language="Latin">panthera tigris</name> <threat>poachers</threat> <weight>&lt500 pounds</weight>



<source sectionid="120" newspaperid="21" /> <picture filename="tiger.jpg" x="200" y="197" /> </animal> </endangered_species>


XML: Displaying elements as text

<?xml version="1.0" ?> <xml_book>

<tags><appearance><![CDATA[ <endangered_species> <animal> <name language="English">Tiger</name> <name language="Latin">panthera tigris</name> <threat>poachers</threat> <weight>500 pounds</weight>  <source sectionid="120" newspaperid="21"></source> <picture filename="tiger.jpg" x="200" y="197"/> </animal> </endangered_species> ]]> </appearance></tags>

</xml_book>


Check point: Understand an XML document


Please visit: Debugging an XML document http://faculty.matcmadison.edu/schmidt/xml/exer1.html

http://faculty.matcmadison.edu/schmidt/xml/exer1.html

Homework

Take a catalogue from a furniture shop Create an XML document


Check point: Create an XML Document[Reference: Allen Schmidt Class Support Home Page]

Items = {Item} <--This means that there are multiple Item entries within Items Item contains Item Number Description Selling Price Cost Quantity On Hand Date Last Received Quantity Sold; Year-To-Date (current) / *modification Warehouse Section Warehouse Shelve {Supplier} <-- This means that there are several suppliers for each item

Instructions First structure the information Then, create the document At the end, validate it!

Documents

Petros KAVASSALIS