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SEMINAR

BỘ MÔN: CƠ SỞ DỮ LIỆU NÂNG CAO. SEMINAR. OBJECT-DATABASE SYSTEMS. Compare. Extend. New data. ODL, OQL. Object-Database. Challenge. Identity. Inheritance. Design. CAD/CAM. Floats. Fixed collection. Complex kind of data. ?. Small. Integers. Relational Database. Multimedia

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SEMINAR

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  1. BỘ MÔN: CƠ SỞ DỮ LIỆU NÂNG CAO SEMINAR OBJECT-DATABASE SYSTEMS

  2. Compare Extend New data ODL, OQL Object-Database Challenge Identity Inheritance Design

  3. CAD/CAM Floats Fixed collection Complex kind of data ? Small Integers Relational Database Multimedia Repositories GIS Dates Typid Data Types Document management Strings

  4. Support more complex kinds of data Two paths • Object-Oriented Database Systems • Good for apps where complex objects play a central role • Influenced by object-oriented PLs • An attempt to add DBMS functionality to a PL environment • Object Data Model & Object Query Language are developed • Object-Relational Database Systems • Extend relational database systems with the functionality necessary to support a broader class of applications Object-Database • Bridge between relational and object-oriented paradigms • RDBMS vendors are adding ORDBMS functionality

  5. Relation Model Object Model ThemeGallery is a Design Digital Content & Contents mall developed by Guild Design Inc. Similar Different Similar Similar Relation Class Instance Object Tuple Column Attribute Store Procedure Method Theo slide ODBMS, Hong Yang, NJIT

  6. Theo slide ODBMS, Hong Yang, NJIT

  7. from Wikipedia

  8. Dinky Entertainment Company • Assets: collection of cartoon characters • Especially: Herbert the Worm • Also licensing Herbert’s image, voice, video • DB: products & films

  9. NEW DATA TYPES • User-defined data types: • Herbert’s image, voice, video footage • Object identity • important to store references instead of copies of objects • Inheritance

  10. IN RDBMS: BLOBs • Binary Large Object • Further processing by the user application program • Not efficient as we have to retrieve all BLOBs in a collection

  11. MANIPULATING THE NEW DATA • Cereal Company: Clog wants to lease an image of Herbert in front of a sunriseSELECT F.Frameno, thumbnail(F.image), C.lease_priceFROM Frames F, Categories CWHERE F.category = C.cid AND is_sunrise(F.image) AND is_herbert(F.image)Frames(Frameno: integer, image: jpeg_image, category: integer)Categories(cid: integer, name: text, lease_price:float, comments: text) • Methods written in an imperative language like Java registered with a DBS: can be used in the same way as built-in methods such as =, +, -, <, >

  12. MANIPULATING THE NEW DATA • Dinky executives want to make sure that a number of Herbert films are playing at theaters near Andorra when the cereal hits the shelvesSELECT N.theater->name, N.theater->address, F.titleFROM Nowshowing N, Films F, Countries CWHERE N.film = F.filmno AND overlaps(C.boundary, radius(N.theater->address,100)) AND C.name = ‘Andorra’ AND ‘Herbert the Worm’ = F.stars[1]theater attribute in Nowshowing is a reference to an object in another tablestars attribute of the Films table is a set of names of each film’s starsNowshowing and Films are joined by the equijoin clauseNowshowing and Countries are joined by the spatial overlap clause

  13. ADDITIONAL FEATURES • User Defined Methods: User defined types are manipulated via their own Methods, for example, is_herbert • Operators for Structured Types:For example, the ARRAY type supports standard array operation of accessing an element • Operators for Reference types: Reference types are dereferenced via an arrow (->) notation

  14. SUMMARY • Traditional relational systems offer limited flexibility in the data types available • Data is stored in tables and the type of each field value is limited to simple atomic types • Limited type systems can be extended in three ways (complex types): • User-defined data types • Structured types • Reference types

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