Class Schedule
21 Aug | intro
23 Aug | clients
28 Aug | servers
30 Aug | networks
04 Sep | basics lab
06 Sep | structural layer
11 Sep | presentational layer
18 Sep | working with layers |
18 Sep | scripting |
25 Sep | images & design
27 Sep | website lab |
XML |
next session
02 Oct | object layers
04 Oct | tools that read markup
09 Oct | document markup lab
11 Oct | spreadsheets, formulas & functions
16 Oct | data display
18 Oct | Fall Break
23 Oct | database tools
25 Oct | spreadsheets lab
30 Oct | relational databases
01 Nov | tables
06 Nov | relationships
08 Nov | input & output
13 Nov | SQL
15 Nov | complex queries
20 Nov | databases lab
22 Nov | Thanksgiving
27 Nov | presentation design
29 Nov | presentation delivery
04 Dec | presentation lab
13 Dec | 0800-1100 | final in class presentation
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We won't use it, but it is good to know about XML.
eXtensible Markup Language (XML) is used to describe data. The XML standard is a flexible way to create information formats and electronically share structured data via the public Internet, as well as via corporate networks.
XML code, a formal recommendation from the World Wide Web Consortium (W3C), is similar to Hypertext Markup Language (HTML). Both XML and HTML contain markup symbols to describe page or file contents. HTML code describes Web page content (mainly text and graphic images) only in terms of how it is to be displayed and interacted with.
XML and HTML were designed with different goals:
XML Does Not Use Predefined Tags
UNIX/LINUX ⇒ | command | argument | value |
HTML ⇒ | tag | attribute | value |
CSS ⇒ | selector | declaration property | declaration value |
JavaScript ⇒ | script | type | text/javascript |
XML ⇒ | tag | attribute | value |
XML data is known as self-describing or self-defining, meaning that the structure of the data is embedded with the data, thus when the data arrives there is no need to pre-build the structure to store the data; it is dynamically understood within the XML. The XML format can be used by any individual or group of individuals or companies that want to share information in a consistent way. XML is actually a simpler and easier-to-use subset of the Standard Generalized Markup Language (SGML), which is the standard to create a document structure.
The basic building block of an XML document is an element, defined by tags. An element has a beginning and an ending tag. All elements in an XML document are contained in an outermost element known as the root element. XML can also support nested elements, or elements within elements. This ability allows XML to support hierarchical structures. Element names describe the content of the element, and the structure describes the relationship between the elements.
An XML document is considered to be "well formed" (that is, able to be read and understood by an XML parser) if its format complies with the XML specification, if it is properly marked up, and if elements are properly nested. XML also supports the ability to define attributes for elements and describe characteristics of the elements in the beginning tag of an element.
XML documents are formed as element trees.
An XML tree starts at a root element and branches from the root to child elements.
All elements can have sub elements (child elements):
<root>
<child>
<subchild>.....</subchild>
</child>
</root>
The terms parent, child, and sibling are used to describe the relationships between elements.
Parent have children. Children have parents. Siblings are children on the same level (brothers and sisters).
All elements can have text content (Harry Potter) and attributes (category="cooking").
<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
<book category="cooking">
<title lang="en">Everyday Italian<</title>
<author>Giada De Laurentiis<</author>
<year>2005<</year>
<price>30.00<</price>
</book>
<book category="children">
<title lang="en">Harry Potter</title>
<author>J K. Rowling</author>
<year>2005</year>
<price>29.99</price>
</book>
<book category="web">
<title lang="en">Learning XML</title>
<author>Erik T. Ray</author>
<year>2003</year>
<price>39.95</price>
</book>
</bookstore>
XML's power resides in its simplicity. It can take large chunks of information and consolidate them into an XML document - meaningful pieces that provide structure and organization to the information.