1. You know my method, Watson. Apply them. SEMINAR BỘ MÔN: CƠ SỞ DỮ LIỆU NÂNG CAO

2. NỘI DUNG Object- Database Extend New data Identity Inheritanc e Design Challeng e ODL, OQL Compar e

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

4. GIỚI THIỆU Object-Database Support more complex kinds of data Object-Oriented Database Systems Object-Relational Database Systems Two paths  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  Extend relational database systems with the functionality necessary to support a broader class of applications  Bridge between relational and object-oriented paradigms  RDBMS vendors are adding ORDBMS functionality

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

6. OBJECT vs RELATIONAL Model Concepts Relational model concept Object model concept Object model benifits Data abstraction Intersection entities and indexing to represent references between tuples. Object identification (OIDS) to directly represent references between objects. Simpler shcema to represent complex data. Inheritance Type codes.Class hierachy.Direct representation of the references between type and subtypes as well as support for specialized processing for each subtype. Encapsulati on "If then else if" code based on type codes and management of the code, usually with libraries. Encapsulation provides built-in dispatching to ensure the correct code executes on the correct data. Reduced application code and reduced chance of error where the wrong code executes on the right data. Theo slide ODBMS, Hong Yang, NJIT

7. HOW ODB WORK? from Wikipedia

8. MOTIVATING EXAMPLE  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 Images Compressed Low- resolution High- resolution

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 sunrise SELECT F.Frameno, thumbnail(F.image), C.lease_price FROM Frames F, Categories C WHERE 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. Dinky executives want to make sure that a number of Herbert films are playing at theaters near Andorra when the cereal hits the shelves SELECT N.theater->name, N.theater->address, F.title FROM Nowshowing N, Films F, Countries C WHERE 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 table stars attribute of the Films table is a set of names of each film’s stars Nowshowing and Films are joined by the equijoin clause Nowshowing and Countries are joined by the spatial overlap clause MANIPULATING THE NEW DATA

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

19. THE END