Object oriented database management

8/10/2019 Object oriented database management

1/21

Object Oriented

DatabaseByRASHMI RAMESH

III Year Chemical EngineeringNIT Trichy

10211205508th October 2014


2/21


3/21

Database Management System

Clients (Services or applications) interact withdatabases through queries (remote or

otherwise) to Create, Retrieve, Update andDelete (CRUD) data within a database. Thisprocess is facilitated through a Database

Management System (DBMS)


4/21

Database Management System

Provides tools for maintenance such as runningsecurity checks, ensuring data integrity, backup

and recovery.

Applications : In all sectors of the modern worldbe it in technology oriented companies orhospitals and health care systems.


5/21


6/21

Data Models (Contd.)

Hierarchical model

This supports parent-child relationships between data similarto a tree data structure where object types are represented bynodes and their relationships are represented by arcs.

This model is restrictive in that it only allows one to many

relationship ( a parent can have many children but a child canonly have one parent)


7/21


8/21

Data Models (Contd.)Object Model

Reduces the overhead of converting informationrepresentation in the database to an application specificrepresentation.

Allows for data persistence and storage by storing objects inthe databases.

The relationships between various objects are inherent in the

structure of the objects. This is mainly used for complex data structures such as 2D and

3D graphics which must otherwise be flattened before storagein a relational database.


9/21

Object Model


10/21


11/21

Object Oriented DatabaseManagement Systems (OODMs)

Object database management systems extend the objectprogramming language with transparently persistent data,concurrency control, data recovery, associative queries, andother database capabilities.

Thus OODB implements OO concepts such as object identity,

polymorphism, encapsulation and inheritance to provideaccess to persistent objects using any OO-programminglanguage


12/21

Objects User defined complex data types. An object has structure or state (variables) and methods

(behavior/operations). An object is described by four characteristics

Identifier: a system-wide unique id for an objectName: an object may also have a unique name in DB(optional)Lifetime: determines if the object is persistent or transient

Structure: Construction of objects using type constructors The state (current value) of a complex object may be

constructed from other objects (or other values) by usingcertain type constructors.

Objects (Contd.)


13/21

Objects (Contd.) An object is associated with it:

A set of variables that contain the data for the object.The value of each variable is itself an object.

A set of messages to which the object responds; eachmessage may have zero, one, or more parameters.A set of methods , each of which is a body of code toimplement a message; a method returns a value as the

response to the message Messages and responses provide the only external interface to

an object.


14/21


15/21

Need for Complex Data Types

Addresses can be viewed as a Single string Separate attributes for each part, or Composite attributes

(which are not in first normal form) Convenient to store multivalued attributes as-is, without

creating a separate relation to store the values in first normalform

Applications :

computer-aided design, computer-aided software engineeringmultimedia and image databases, and document/hypertextdatabases.


16/21

Features Of OODMs

New features relational & Object oriented

Relational Features new data types, newpredicates, enhanced semantics, additionalsecurity and an active database.

Object Oriented Features support for functionsand procedures.


17/21


18/21

Relational and Object Models Queries look very similar in SQL and OQL, sometimes they are

the same In fact, the results they give are very different Query returns:

OQL - ObjectSQL - Collection of objects, Tuple, Table


19/21

Relational and Object Models(Contd.)

A method in an object model is defined in the class to whichthe object belongs.

A stored procedure is a sub-routine available to applicationsand this is external to the database , defined in the datadictionary.

Example: Stored procedures for data validation OODB is OO language specific whereas Relational DB are

language independent via SQL No impedance mismatch in applications using OODB where as

object relational mapping must be performed in relationaldatabase for use in OO applications.


20/21

Object Query Language

Example of OQL with integration to OO Language: Create objects as in OO languages and then make them

persistent using the set() method on the database.

Person p1 = new Person(Pikes Peak", 78); db.set(p1); Retrieve by age (null default for string)

Person p = new Person (null, 35); ObjectSet result = db.get(p);


21/21

Thank You

Documents

Object oriented database management