A DBMS is software that:Acts as an interface between application programs and the data files.Helps to reduce data redundancy and eliminate data inconsistency by allowing a central, shared data source

1. DATABASE MANAGEMENT
SYSTEM
Prepared by
NIJAZ N

2. ORGANIZING DATA IN A TRADITIONAL FILE
ENVIRONMENT
 Organize data in fields ,records and files.
 Field - A grouping of characters into a word, a group of words or a
complete number (eg: person’s name or age) is called a field.
 Record – A group of related fields comprises a record (eg: student’s
name, course taken, date and grade)
 File - A group of records of the same type (eg: course file)
 Difficult to keep track of all the pieces of data.
 Different functional areas and groups were allowed to develop their own
files independently.

3. PROBLEMS WITH FILE SYSTEM
Data Redundancy • Presence of duplicate data in multiple files so that
the same data are stored in more than one place or
location.
Data Inconsistency • Same data may have different values.
Lack of flexibility • Difficult to deliver ad hoc reports or respond to
unanticipated information requirements in a timely
fashions.
Poor Security •Little control over data or access of data.
Lack of Data Sharing • Information cannot flow freely across different
functional areas

4. DATABASE
 Is a collection of data organized.
 Serve many applications efficiently by
 Centralizing the data
 Controlling the redundant data.
 A single database services multiple application rather than storing data in
separate files for each application.
 E.g.:-
 A University database through which university applications from the
Registrar’s office, the Accounting department, and the Examination
department access data

5. DBMS
 Software that defines a database, stores the data, supports a query
language, produces reports, and creates data-entry screens.
 A DBMS is software that:
 Acts as an interface between application programs and the data files.
 Helps to reduce data redundancy and eliminate data inconsistency by
allowing a central, shared data source

6. Physical view
DBMS
Logical View
LOGICAL & PHYSICAL VIEW
Data as perceived by
end users/business
specialists
How data are actually
organized on physical
storage media

7. DBMS
Data
definition
Language
DDL
Data
Dictionary
Data
Manipulation
Language
DML
DBMS – COMPONENTS/REQUIREMENTSFormal language used
by the programmers
to specify the
structure/content of
the database
Contains commands
that permit end users
to extract data from
the database to satisfy
information requests
Automated/manual
file that stores
definitions of data
elements and data
characteristics

8. DATABASE MODELS /TYPES
Database
Models
Relationship
Model
Hierarchical
Model
Network
Object
Oriented

9. RELATIONSHIP MODEL
 Proposed in 1969 by Edgar F. Codd
 Depicts data logically as many-to-many relationships
 All data is represented in terms of tuples, grouped into relations
Order list of elements

10. HIERARCHICAL MODEL
 Organizes data in a tree-like structure
 Supports one-to-many /parent-child relationships
 Prevalent in large legacy systems

11. NETWORK MODEL
 Depicts data logically as many-to-many relationships
 Object types are nodes and relationship types are arcs

12. OBJECT ORIENTED MODEL
 Organizes data in a tree-like structure
 Supports one-to-many parent-child relationships
 Prevalent in large legacy systems