Compare
Sponsored Links
This presentation is the property of its rightful owner.
1 / 21

Object-Database PowerPoint PPT Presentation


  • 94 Views
  • Uploaded on
  • Presentation posted in: General

Compare. Extend. New data. ODL, OQL. Object-Database. Challenge. Identity. Inheritance. Design. Objectives. Overview of ODMG Data Model Object Data Language – ODL Object Query Language - OQL. ODMG Data Model. Conceived by ODMG in 1991.

Download Presentation

Object-Database

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Compare

Extend

New data

ODL, OQL

Object-Database

Challenge

Identity

Inheritance

Design


Objectives

  • Overview of ODMG Data Model

  • Object Data Language – ODL

  • Object Query Language - OQL


ODMG Data Model

  • Conceived by ODMG in 1991.

  • Provides a standard model for object databases.

  • Supports object definiton via ODL.

  • Supports object querying via OQL.

  • Supports a variety of data types and type constructor.

  • The basis for an OODBMS.


Object vs Class

Collection of object

OBJECT

CLASS

Unique oid

Same properties

Using Object Data Language to specify properties of class.


Object Data Language – ODL

  • ODL supports semantics constructs of OODBMS.

  • ODL is independent of any programming language.

  • ODL is used to create object specification (classes and interfaces)

  • ODL is not used for database manipulation.


Class

CLASS

attributes

methods

relationships


Class

  • Atrributes: atomic type or structured type.

  • Methods:

    • Functions that can be applied to objects of the class.

    • No analog to methods in the ER or relational models.


Class

  • Relationships:

    • Type is a reference to an object or a collection such references.

    • Show how an object is related to one or more objects of the same class or of a different class.

    • Has a corresponding inverse relationship.


Example

showAt

nowShowing


Example


Example


Example


Object Query Language - OQL

  • OQL is ODMG’s query language.

  • OQL works closely with programming languages such as C++.

  • Embedded OL statement return objects that are compatible with the type system of the host language.

  • OQL’s syntax is similar to SQL with additional features for object.


Example


Example


Example


Compare

Extend

New data

ODL, OQL

Object-Database

Challenge

Identity

Inheritance

Design


RDBMS versus ORDBMS

  • RDBMS does not support the extensions that ORDBMS supports.

  • Relational system is easier to use because there are fewer features to master.

  • RDBMS is less versatile than an ORDBMS.


OODBMS vs ORDBMSSimilarities

  • Both support user-defined ADTs, structired types, object type and inheritance.

  • Both support a query language for manipulating collection type:

    • ORDBMS: extended form of SQL

    • OODBMS: ODL/OQL.

  • ORDBMS add OODBMS features to an RDBMS.

    OODBMS have developed query language based on relational query language.

  • Both provide DBMS functionality.


OODBMS vs ORDBMSDifferences

  • OODBMS try to add DBMS functionality to a programming language, whereas ORDBMS try to add richer data type ro a relational DBMS.

  • OODBMS aim to achieve seamless integration with a programming language, whereas it’s not an important goal for an ORDBMS.


OODBMS vs ORDBMSDifferences

  • The query facilities of OQL are not support efficiently in most OODBMS, whereas they are the centerpiece of an ORDBMS.

  • OODBMS have been optimized to directly support object oriented applications and specific OO languages.

    ORDBMSs are supported by most of the ‘major players’ in the DBMS market place.


  • Login