Introduction to XML for Building Data Management

1
Introduction to XML for Building Data Management

• Frank Olken
• Lawrence Berkeley National Laboratory

2
Overview

• What is XML?
• Why use XML?
• What is a DTD or Schema?
• Why use a schema?
• Content Standards Needed

3
Example of XML

• ltcar_for_salegt
• ltmakegt Volvo lt/makegt
• ltmodelgt 245 Station Wagon lt/modelgt
• ltyeargt 1975 lt/yeargt
• ltcolorgt orange lt/colorgt
• ltprice currencyUSDgt 700 lt/pricegt
• ltphonegt 510-486-5891 lt/phonegt
• lt/car_for_salegt

4
Another example of XML

• ltarticlegt
• lttitlegt Clinton Impeached lt/titlegt
• ltauthorgt Daniel Schorr lt/authorgt
• ltbodygt
• ltpgt Clinton was impeached today . lt/pgt
• ltpgt The Republican Congress voted . lt/pgt
• ltbodygt
• lt/articlegt

5
What is XML?

• XML is a markup metalanguage
• Markup language
• means of marking up documents and/or data
  exchange, a.k.a. tagging
• markup delimit fields, document structure
• Metalanguage
• Designer can specify application-specific set of
  tags

6
Tagging (Markup)

• To delimit structure of documents
• author, title, heading, paragraph, section,
  citation, footnote
• To delimit fields in data exchange records, e.g.,
  in purchase order
• date, shipping address, billing address,
  quantity, description, price

7
What is a DTD or XML Schema?

• DTD Document Type Definition
• DTD specifies elements (tags), attributes, order
  and nesting of elements (tags)
• XML Schema (new) also specifies data types
  integer, floating point numbers, dates, times,
  strings, URLs,
• Provide grammar for document tags

8
Why use XML Schema ?

• To facilitate data validation
• Validating parser can check
• correct syntax
• correct data types (integer, float, date, string)
• Avoids need to write custom data validators

9
Why use XML?

• Technical advantages
• Human readable, flexible, extensible, typed,
• Social advantages
• IBM, Microsoft, Oracle, Sun, et al. agree
• Many software tools
• parsers, editors, DB loaders/unloaders, query
  engines, formatters, translators, .
• Becoming lingua franca for data exchange

10
Advantages of XML Usage

• For documents
• single source file - multiple media (paper, Web)
• more precise information retrieval
• distinguish Washington as state, city, person,
  univ.
• For data exchange
• more flexible than traditional EDI
• less error prone than traditional EDI or comma
  separated variable (CSV) formats
• many more software tools

11
Applications for Buildings

• Design Phase
• analysis tools energy efficiency, structural,
• cost estimation tools
• automated checking of building codes
• Construction and Operations Phases
• purchasing building materials
• facilities management, insurance, leasing,
• emergency response (fire, earthquake, )

12
Why not use EDI, STEP, ??

• Existing EDI is obscure, inflexible, often vague,
  error prone,
• EDI Electronic Data Interchange (X12)
• STEP Express Part 21 design data exchange
• STEP (std for the exchange of product data)
• has limited vendor support (expensive)
• unsuited to documents
• unpopular for e-commerce transactions

13
Content Standards Needed

• XML is pure syntax
• What tag sets to use?
• What to they mean?
• Need content standards
• tags, definitions,
• Current status Tower of Babel
• many, many ill-specified content standards

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It is the semantics, stupid !!

• Semantic specification is hard.
• Often, unwitting misunderstandings
• Currently rely on English definitions
• Trans-lingual semantic specifications??
• Measurement units often unclear.
• Need authoritative citations for semantics
• legislation, regulations, contracts, standards,
  ...

15
IAI Data Modeling

• Content modeling for AEC industry
• Semantics of building data
• Requires
• subject area (AEC) expertise
• data modeling expertise
• Lengthy, expensive development

16
Acknowledgements

• XML Standards work is supported by the U.S.
  Environmental Protection Agency
• XML Standards work is joint work with John L.
  McCarthy (LBNL).

17
Contact Information

• Frank Olken
• olken_at_lbl.gov
• http//www.lbl.gov/olken
• Tel [phone]
• Fax [phone]
• Lawrence Berkeley National Laboratory, 1
  Cyclotron Road, Mailstop 50B-3238,
  Berkeley, CA 94720