OBJECT ORIENTED DATABASE

NAME- AJAYKANT JHAEXAM NO- 2845

TY BCA SEM 6TH SDJ INTERNATIONAL COLLEGE

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OUTLINE

Types of database Object oriented database Objects Comparison of oodbs and rdbs Conclusion References

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TYPES OF DATABASE

Hierarchical

Network

Relational Object Oriented

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DIFFERENCES

The first database systems (early ‘60s and before) used a hierarchical arrangement where, for example, parts were stored as sub-elements of the supplier that supplied them.

This approach had several disadvantages, including the introduction of an unnecessary degree of asymmetry.

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DIFFERENCES

To overcome the asymmetry problem, network databases (mid ‘60s) came into being.

These were mainly pointer-based structures. Querying and traversal was a low-level procedural affair.

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DIFFERENCES

Relational systems were born in 1969 and were soon recognised as a drastic simplification over the previous models.

Everyone agreed that relational was a good thing.

However it took a good decade before the commercial systems could catch up with the theory.

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DIFFERENCES

The late ‘80s saw the emergence of object oriented database systems as a response to the requirements of applications like CAD which dealt with many complex, nested objects.

The field is still evolving very rapidly and, although everyone agrees that some degree of objectness is useful, there is no unanimous consensus on what exactly an OODBMS should be.

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RELATIONAL MODEL OF A ‘CAT’ RELATIONAL MODEL OF A ‘CAT’

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OO MODEL OF A ‘CAT’ Applications

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OBJECT ORIENTED DATABASE

Object-Oriented DBMS(OODBMS) are DBMS based on an ObjectOriented Data Model inspired by OO programming languages

OODBMS are capable of storing complex objects, I.e., objects that are composed of other objects, and/or multi-valued attributes

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OBJECT ORIENTED FEATURES

User-defined data types

Nested objects

Containers: sets, lists, bags...

Methods (precursor: stored procs)

Preserve strong typing across interface

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KEY BENEFITS OF ODBMS

Sharing in highly distributed environment Easier to share and distribute objects than tables

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KEY BENEFITS OF ODBMS

Better memory usage and less paging 1. Bringing only objects of interest Object-oriented

databases can reduce the need for paging b

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STRENGTHS

Rich type system

Better at modelling complex objects

Better performance on certain data structures

No impedance mismatch

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OBJECTS

Objects are used in object oriented languages such as C++, Java, and others.

Objects basically consist of the following:

Attributes - Attributes are data which defines the characteristics of an object. This data may be simple such as integers, strings, and real numbers or it may be a reference to a complex object.

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OBJECTS Methods - Methods define the behavior of an object and

are what was formally called procedures or functions.

Therefore objects contain both executable code and data.

There are other characteristics of objects such as whether methods or data can be accessed from outside the object.

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WHEN TO USE OBJECT DATABASES

Object databases should be used when there is complex data and/or complex data relationships.

This includes many to many object relationship.

Object databases should not be used when there would be few join tables and there are large volumes of simple transactional data.

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WHY OBJECT-ORIENTED DATABASES?

Because object-oriented databases are good at handling BLOBs, and the new world of information is all about BLOBs.

BLOB - Binary Large Object. Like:

• Images • Video • Audio • Animations• Mixed Media

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DIFFERENT FROM RDBS An OOD and its database management system (DBMS) is

aware of how to

Access or extract internal components of an object. For example, one or two frames of a video.

Execute operations or functions against objects without exporting them to the client.

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DIFFERENT FROM RDBS Extract enough about the object to develop an "intelligent"

search plan to optimize performance.

For example: The user wants multiple frames of a video, plus info on actors, royalties and rights.

The OODBMS gauges the speed of retrieval for each item and optimizes a retrieval plan using SERVER resources, freeing the client to continue work.

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HOW DATA IS STORED Two basic methods are used to store objects by different

database vendors

Each object has a unique ID and is defined as a subclass of a base class, using inheritance to determine attributes.

Virtual memory mapping is used for object storage and management.

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COMPARISON

Criteria RDBMS ODBMS

Support for object oriented

programming

Poor Direct and extensive

Simplicity of use Table structures easy to

understand

OK for programmers; some

SQL access for end users

Extensibility and content None users can write methods and

on any structure

Complex data relationships Difficult to model Can handle arbitrary

complexity

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ADVANTAGES OVER RDBMS

Reduced paging

Better concurrency control - A hierarchy of objects may be locked

Data model is based on the real world.

Less code required when applications are object oriented.

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DISADVANTAGES COMPARED TO RDBMS

Lower efficiency when data is simple and relationships are simple.

Relational tables are simpler.

Standards for RDBMS are more stable.

Support for RDBMS is more certain and change is less likely to be required.

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CONCLUSION

Object Oriented Database deals with the complex data or we can say object which are not accessed by any of the database.

Blobs like Videos, Animation and Image.

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REFERENCES

www.cs.sfu.ca/CourseCentral/354/zaiane/material/notes/Chapter9/node13.html

people.cs.pitt.edu/~chang/156/19oodb.html

www.axswave.com/weblibry/relobjdb.htm

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THANK U

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