8 April: Announcements/Assignments 8-Apr C12-14 Quiz? C18 XML:Managing Data Exchange (http://en.wikibooks.org/wiki/XML) 13-Apr - Visiting Speaker - Dr. Richard T. Watson C15 - Organizational Intelligence Technologies (Reading Assignment) 15-Apr - DB2 Presentations Begin C19 Data Integrity, C15 Quiz? 20-Apr - DB2 Presentations C20 - Data Administration Chapter 18 XML: Managing data exchange Words can have no single fixed meaning. Like wayward electrons, they can spin away from their initial orbit and enter a wider magnetic field. No one owns them or has a proprietary right to dictate how they will be used. David Lehman, End of the Word, 1991. Summary XML is a significant technological development Its main purpose is to support data exchange It will lower the cost of business transactions It is a critical data management technology Central problems of data management Capture Storage Retrieval Exchange Covered 1-3 w/SQL EDI (Electronic Data Interchange) Electronic exchange of standard documents In use for some 20 years Standards ANSI X.12 (US and Canada) http://www.x12.org/x12org/about/X12History.cfm EDIFACT (International) http://en.wikipedia.org/wiki/EDIFACT Primary goal of XML is to support data interchange EDI: Advantages Paper handling is reduced, saving time and money Data can be exchanged in real time There are fewer errors since data are keyed only once Enhanced data sharing enables greater coordination of activities between business partners Money flows are accelerated and payments received sooner Examples? EDI: Adoption Much information flow is still on paper Electronic exchange is the exception rather than the rule for many customer transactions SGML Document management consumes 15% of company revenue 25% of labor costs 10 - 60% of an office worker?s time Standard generalized markup language (SGML) was designed to reduce the cost of document management Markup language Embedded information within text about the meaning of the text This uniquely creative collaboration between Miles Davis and Gil Evans has already resulted in two extraordinary albums?Miles AheadCL 1041> and Porgy and Bess CL 1274. SGML A vendor independent standard for publication of all media Cross system Portable Defines the structure of a document The parent of HTML and XML SGML: Advantages Re-use Same advantage as with word processing Flexibility Generate output for multiple media Revision Version control SGML code 18

Words can have no single fixed meaning. Like wayward electrons, they can spin away from their initial orbit and enter a wider magnetic field. No one owns them or has a proprietary right to dictate how they will be used. ?

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18

XML: Managing Data Exchange

Words can have no single fixed meaning. Like wayward electrons, they can spin away from their initial orbit and enter a wider magnetic field. No one owns them or has a proprietary right to dictate how they will be used.

The problem with HTML Presentation not meaning Reader must infer meaning Machines are not very good at inferring meaning XML Extensible markup language SGML for e- and m-commerce A meta-language A language to generate languages Will steadily replace HTML Primary goal of XML is to support data interchange XML vs. HTML Structured text User-definable structure Context-sensitive retrieval Greater hypertext linkage Formatted text Pre-defined format Limited retrieval Limited hypertext linking XML rules Elements must have both an opening and closing tag Elements must follow a strict hierarchy with only one root element Elements may not overlap other elements Element names must obey XML naming conventions XML is case sensitive HTML vs. XML HTML XML

MIST4610 Data Management
3 credit hours

MIST4610 3 Processing shift From server to browser Browser can ?read? meaning of the data Less data transmitted HTML XML Retrieve shirt data with prices in $US Retrieve shirt data with prices in euros Retrieve shirt data with prices in $US Retrieve conversion rate of $US to euro Retrieve Java program to convert currencies Compute prices in euros Searching Search engines look for appropriate tags in the XML code Faster More precise Expected gains Store once and format many times Hardware and software independence Capture once and exchange many times Accelerated targeted searching Less network congestion XML language design Designers must define Allowable tags Rules for nesting tags Which tagged elements can be processed Typical steps (following slides) Create a hierarchical data model ? document object module (DOM) Define a Data Schema (.xsd) Create an XML file containing data (.xml) Create an XSL file containing a stylesheet (.xsl) DOM (p514) Document object model (DOM) The data model for an XML document A tree (1:m) .xml XML Schema (.xsd) The schema defines The names and contents of all elements that are permissible in a certain document The structure of the document How often an element might appear The order in which the elements must appear The type of data the element contains .xsd Schema for CD Library (cdlib.xsd) XML declaration and root of all schema documents 1 2 See Table 18-8, P514 Schema (cdlib.xsd) CD library definition Schema (cdlib.xsd) CD definition Schema (cdlib.xsd) Track definition XML for describing CD (cd.xml) A2 1325 Atlantic Pyramid 1960 1 Vendome 2:30 ? Partial data - See Table 18-11, P517 for complete description XSL eXtensible Stylesheet Language (XSL) Stylesheet tells the browser how to display an XML file Defines how an XML document is rendered An XML file

Complete List of Songs

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Stylesheet for displaying XML file of CD data (cd.xsl) p519
cd.xsl (continued) XSL Results of applying cd.xsl Pyramid, Atlantic, 1960 [A2 1325] 1 Vendome 00:02:30 2 Pyramid 00:10:46 Ella Fitzgerald, Verve, 2000 [D136705] 1 A tisket, a tasket 00:02:37 2 Vote for Mr. Rhythm 00:02:25 3 Betcha nickel 00:02:52 XML and databases XML is a data management tool XML documents will be stored for the long-term Need a DBMS DBMS requirements Store a large number of documents; Store large documents Support access to portions of a document (e.g., the data for a single CD in a library of 20,000 CDs) Concurrent access Version control Integrate data from other sources Database to XML A significant proportion of Web pages are generated from databases Instead of converting to HTML these should be converted to XML Render with XSL Need tools for converting relational data to XML Conclusion XML is a significant technological development Its main purpose is to support data exchange It will lower the cost of business transactions It will be a critical data management technology XML Assignments/Exercises Complete Skill Builder exercises: P516 ? construct a schema to describe CD library P519 ? construct a stylesheet to display the xml CD file http://www.richardtwatson.com/dm5e/ Support Tab => XML p P519 ? XML Skillbuilder Exercise P519 ? construct a stylesheet to display the xml CD file Download cdlib.xsl, cdlib.xsd, cdlib.xml into a directory http://www.richardtwatson.com/dm5e/ - Go to Support>XML section 2. Edit a copy of cdlib.xml (insert 2nd line): Save file (from step 2) as cdlibv3.xml in same directory and open with browser Change cdlibv2.xml (steps 2, 3)