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Dr. Abid Sohail Bhutta
abidbhutta@cuilahore.edu.pk
Department of Computer
Science,
COMSATS University , Lahore
Campus
Database Systems
Lecture 7
Object Orientated Data Model (OODB)
and Relational Data Model (RDB)
Recall Lecture 6
HDBS (Hierarchical)
NWDB (Network)
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OBJECT-ORIENTED
DATABASE (OODB)
The ODBMS which is an abbreviation
for object oriented database management
system, is the data model in which data is
stored in form of objects, which are instances
of classes. These classes and objects
together makes an object oriented data
model.
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OODB a simpler Example
class CLERK
{
//variables
char name;
string address;
int id; int salary;
//messages
char get_name();
string get_address();
int annual_salary();
};
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Data Object in OODB
{
"_id" : "37010"
"city" : "ADAMS",
"pop" : 2660,
"state" : "TN",
“councilman” : {
name: “John Smith”
address: “13 Scenic Way”
}
}
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OODB Data Object
book = {
title: “DBMS: The Definitive Guide",
authors: [ "Kristina Chodorow", "Mike Dirolf" ]
published_date: ISODate("2010-09-24"),
pages: 216,
language: "English",
publisher: {
name: "O’Reilly Media",
founded: "1980",
location: "CA"
}
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Array of Data Objects
{
"anObject": {
"numericProperty": -122,
"stringProperty": "An offensive \" is problematic",
"nullProperty": null,
"booleanProperty": true,
"dateProperty": "2011-09-23"
},
"arrayOfObjects": [
{
"item": 1
},
{
"item": 2
},
{
"item": 3
}
],
"arrayOfIntegers": [
1,
2,
3,
4,
5
]
}
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Advantages and Disadvantages
Advantages
Real world modeling
Model simplicity
Reduced data size
Advantages
Lack of SQL query language
Lack of automotive constraints
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Relational Database Model (RDBM)
Let’s user or database designer to operate
human logical environment
Perceived by user as a collection of tables for
data storage, while let RDBMS handles the
physical details.
Tables are a series of row/column intersections
Tables related by sharing common entity
characteristics
It allows 1:1, 1:M, M:N relationships
Relational Database Model
Relational Database Model
Advantages
Structural independence: data access path is
irrelevant to database design; change structure will
not affect the database
Improved conceptual simplicity
Easier database design, implementation,
management, and use
Ad hoc query capability with SQL (4GL is added)
Powerful database management system
Relational Database Model
Disadvantages
Substantial hardware and system software
overhead
Poor design and implementation is made
easy
May promote “islands of information”
problems
Data Models
Object-based
Entity-relationship
Semantic
Knowledge-based
Functional
Object-oriented
Record-based (transactions) Object-relational
Relational
Network Transaction-based
Hierarchical
Physical
How data are stored
Unifying
Frame memory
Summary -Record-Based Data Models
Relational (Oracle, DB2, Sybase, Informix, SQL
7, Ingres, etc.)
Based on concepts of mathematical relations
Tables, rows, columns
Network (CODASYL - Conference on Data
System Languages) (Image)
Many-to-many relationships
Record types, data items
Hierarchical (IMS)
Segment types, fields
In COBOL: files, records, fields
