1 / 9

Databases : Object-Oriented DB

Databases : Object-Oriented DB. 2007, Fall Pusan National University Ki-Joune Li. Object-Oriented DB. Weak Points of Relational DB Lack of Expressive Power Non 1NF Impedance Mismatch Mismatches between DB and Host Languages Demands for complicated DB in late 1980s

zyta
Download Presentation

Databases : Object-Oriented DB

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Databases : Object-Oriented DB 2007, Fall Pusan National University Ki-Joune Li

  2. Object-Oriented DB • Weak Points of Relational DB • Lack of Expressive Power • Non 1NF • Impedance Mismatch • Mismatches between DB and Host Languages • Demands for complicated DB in late 1980s • CAD, GIS, VLSI DB, Multimedia • Need more expressive power • Relational Data Model • Good since it is simple • Bad since it lacks of expressive power

  3. Relational Model: Lack of Expressive Power • Example • Description of Road Network by Relational Data Model • How to compute the shortest path from two points • Navigation by Point number: extremely expensive • Why this problem? : Lack of Expressive Power

  4. Relational Model: 1NF • 1NF: Only Atomic Value in a field • Example Neither very natural,Nor efficient

  5. Relational Model: 1NF • Non-1NF: Any Type for a field • Set, List, Table • NO MORE Relational Algebra • No Selection, No Join etc.. • User-Defined Type • Example OK

  6. Relational Model: Impedance Mismatch • Separation between Data and Program • Data: Relational Algebra: Declarative Approach • Program: Procedural Language like Java and C  Totally different approaches • Impedance Mismatch • Difficult to develop Program Mismatch DB

  7. Persistent Object • Objects in OOPL like Java, Smalltalk, and C++ • Persistency: • The states of objects remain after the termination of program • OOPL: Not persistent • If Persistent  DB and OO DB • Persistent Object • NO MORE Impedance Mismatch • Functions for DB in language itself • OOPL + DB • Persistent Type • Example • Persistent Smalltalk • Persistent C++ • Persistent Java

  8. Stored Procedure in OODB • Example: Polygon • Data • Methods (Operations) • Intersect, • Contain, • Etc.. Persistent Object Program Program Stored Procedure Data DB Polygon Data Intersect Contain Etc..

  9. Some Important Aspects of OODB • Object Identifier • User-Defined Type • Version Control

More Related