XML Structure of XML Data XML Document Schema Querying and Transformation Application Program Interfaces to XML Storage of XML Data XML Applications Database System Concepts-5th Edition,Aug 22,2005. 10.2 @Silberschatz,Korth and Sudarshan
Database System Concepts - 5 10.2 ©Silberschatz, Korth and Sudarshan th Edition, Aug 22, 2005. XML Structure of XML Data XML Document Schema Querying and Transformation Application Program Interfaces to XML Storage of XML Data XML Applications
Introduction XML:Extensible Markup Language Defined by the WW Consortium(W3C) Derived from SGML(Standard Generalized Markup Language),but simpler to use than SGML Documents have tags giving extra information about sections of the document E.g.<title>XML </title><slide>Introduction...</slide> Extensible,unlike HTML Users can add new tags,and separately specify how the tag should be handled for display Database System Concepts-5th Edition,Aug 22,2005. 10.3 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 5 10.3 ©Silberschatz, Korth and Sudarshan th Edition, Aug 22, 2005. Introduction XML: Extensible Markup Language Defined by the WWW Consortium (W3C) Derived from SGML (Standard Generalized Markup Language), but simpler to use than SGML Documents have tags giving extra information about sections of the document E.g. <title> XML </title> <slide> Introduction …</slide> Extensible, unlike HTML Users can add new tags, and separately specify how the tag should be handled for display
XML Introduction (Cont.) The ability to specify new tags,and to create nested tag structures make XML a great way to exchange data,not just documents. Much of the use of XML has been in data exchange applications,not as a replacement for HTML Tags make data(relatively)self-documenting E.g. <bank> <account> <account number>A-101 </account number> <branch name> Downtown </branch name> <balance> 500 </balance> </account> <depositor> <account number>A-101 </account number> <customer name>Johnson </customer name> </depositor> </bank> Database System Concepts-5th Edition,Aug 22,2005. 10.4 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 5 10.4 ©Silberschatz, Korth and Sudarshan th Edition, Aug 22, 2005. XML Introduction (Cont.) The ability to specify new tags, and to create nested tag structures make XML a great way to exchange data, not just documents. Much of the use of XML has been in data exchange applications, not as a replacement for HTML Tags make data (relatively) self-documenting E.g. <bank> <account> <account_number> A-101 </account_number> <branch_name> Downtown </branch_name> <balance> 500 </balance> </account> <depositor> <account_number> A-101 </account_number> <customer_name> Johnson </customer_name> </depositor> </bank>
XML:Motivation Data interchange is critical in today's networked world Examples: Banking:funds transfer Order processing (especially inter-company orders) Scientific data -Chemistry:ChemML,... -Genetics:BSML (Bio-Sequence Markup Language),... Paper flow of information between organizations is being replaced by electronic flow of information Each application area has its own set of standards for representing information XML has become the basis for all new generation data interchange formats Database System Concepts-5th Edition,Aug 22,2005. 10.5 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 5 10.5 ©Silberschatz, Korth and Sudarshan th Edition, Aug 22, 2005. XML: Motivation Data interchange is critical in today’s networked world Examples: Banking: funds transfer Order processing (especially inter-company orders) Scientific data – Chemistry: ChemML, … – Genetics: BSML (Bio-Sequence Markup Language), … Paper flow of information between organizations is being replaced by electronic flow of information Each application area has its own set of standards for representing information XML has become the basis for all new generation data interchange formats
XML Motivation (Cont.) Earlier generation formats were based on plain text with line headers indicating the meaning of fields Similar in concept to email headers Does not allow for nested structures,no standard"type"language Tied too closely to low level document structure(lines,spaces,etc) Each XML based standard defines what are valid elements,using XML type specification languages to specify the syntax DTD(Document Type Descriptors) XML Schema Plus textual descriptions of the semantics XML allows new tags to be defined as required However,this may be constrained by DTDs A wide variety of tools is available for parsing,browsing and querying XML documents/data Database System Concepts-5th Edition,Aug 22,2005. 10.6 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 5 10.6 ©Silberschatz, Korth and Sudarshan th Edition, Aug 22, 2005. XML Motivation (Cont.) Earlier generation formats were based on plain text with line headers indicating the meaning of fields Similar in concept to email headers Does not allow for nested structures, no standard “type” language Tied too closely to low level document structure (lines, spaces, etc) Each XML based standard defines what are valid elements, using XML type specification languages to specify the syntax DTD (Document Type Descriptors) XML Schema Plus textual descriptions of the semantics XML allows new tags to be defined as required However, this may be constrained by DTDs A wide variety of tools is available for parsing, browsing and querying XML documents/data