OBJECT ORIENTED DATA MODEL

GENERAL INTRODUCTION

1. OBJECT ORIENTED DATA MODEL SUBMITTED TO : MR.GAURAV KALOTRA SUBMITTED BY : PRIYANKA KOHLI SHEETAL MALIK

2. INTRODUCTION OBJECT : REAL WORLD ENTITIES HEART OF OBJECT ORIENTED APPROACH OBJECT ORIENTATION: VIEWING AND MODELLING THE WORLD OR SYSTEM AS A SET OF INTERACTING &INTERRELATED OBJECTS. OBJECT ORIENTED MODELLING: FOCUSES ON THE DESIGNING OF OBJECT ORIENTED SYSTEMS. MODEL: IT CAN BE DEFINED AS AN ABSTRACTION OF SOMETHING BEFORE IT IS ACTUALLY DEVELOPED ,INSTALLED OR PUT INTO PRACTICE. A MODEL IS AN ABSTRACTION OF SOMETHING FOR THE PURPOSE OF UNDERSTANDING IT BEFORE BUILDING IT.

3. ELEMENTS OF OODM OBJECTS: THE REAL WORLD ENTITIES AND SITUATIONS ARE REPRESENTED AS OBJECTS IN THE OODM. ATTRIBUTES AND METHOD: EVERY OBJECT HAS CERTAIN CHARACTERISTICS.THESE ARE REPRESENTED USING ATTRIBUTES.THE BEHAVIOUR OF THE OBJECT IS REPRESENTED USING METHODS. CLASS: SIMILAR ATTRIBUTES AND METHODS ARE GROUPED TOGETHER USING A CLASS. AN OBJECT CAN BE CALLED AS AN INSTANCE OF THE CLASS. INHERITANCE: A NEW CLASS CAN BE DERIVED FROM THE ORIGINAL CLASS. THE DERIVED CLASS CONTAINS ATTRIBUTES AND METHODS OF THE ORIGINAL CLASS AS WELL AS ITS OWN.

4. FEATURES WHICH DISTINGUISH OODM FROM TRADITIONAL DATABASE SYSTEMS GENERIC PROPERTIES: THERE SHOULD BE AN INHERITANCE RELATIONSHIP WITH MANY NUMBER OF CLASSES AND SUBCLASSES. ABSTRACTION: OBJECTS,CLASSES AND SUPER CLASSES ARE TO BE GENERATED BY CLASSIFICATION, GENERALIZATION, ASSOCIATION AND AGGREGATION. ADHOC QUERIES: USERS CAN HAVE ANY SPATIAL OPERATION TO OBTAIN SPATIAL RELATIONSHIPS OF GEOGRAPHIC OBJECTS USING SOME CONCISE ‘ HIGH LEVEL’ LANGUAGES.

5. ADVANTAGES THEY ARE MORE EFFICIENT TO MANAGE THE COMPLEX RELATIONSHIPS BETWEEN OBJECTS THROUGH AN EASY MAINTENANCE AND UPDATING.FOR EXAMPLE, A LINE MAY BE A BOUNDARY OF LAND OR PROPERTY, A ROAD EDGE, OR SOMETHING ELSE. IN AN OODM, IT NEEDS TO BE UPDATED ONLY ONCE , WHILE IN OTHER DATABASE SYSTEMS IT REQUIRES MULTIPLE UPDATING OPERATIONS. BECAUSE OF ITS INHERITANCE PROPERTY, WE CAN RE-USE THE ATTRIBUTES AND FUNCTIONALITIES IT REDUCES THE COST OF MAINTAINING THE SAME DATA MULTIPLE TIMES ALSO, THESE INFORMATION ARE ENCAPSULATED AND,THERE IS NO FEAR BEING MISUSED BY OTHERS OBJECTS SINCE EACH CLASS BINDS ITS ATTRIBUTES AND ITS FUNCTIONALITY, IT IS SAME AS REPRESENTING THE REAL WORLD OBJECT.

6. DISADVANTAGES  In comparison to RDBMSs the use of OODBMS is still relatively limited. This means that we do not yet have the level of experience that we have with traditional systems. Also there is a resistance to the acceptance of the technology. While the OODBMS is limited to a small niche market, this problem will continue to exist.  The increased functionality provided by the OODBMS (such as the illusion of a single-level storage model, pointer swizzling , version management, and schema evolution) makes the system more complex than that of traditional DBMSs. In complexity leads to products that are more expensive and more difficult to use. Currently, OODBMSs do not provide adequate security mechanisms. The user cannot grant access rights on individual objects or classes. of the most significant issues that face OODBMS vendors is the competition posed by the RDBMS and the emerging  ORDBMS  products. These products have an established user base with significant experience available.