



Introduction

Med.elhedhli@mailpost.tn

Mohamed HEDHLY
 Presentation
 Examples

 Characteristics
 Data independence
•
•



Data models
•
•
•
•



Physical independence
Log...
 Database

management systems is a
software package that allows users to
create, edit, query, update and administrate
Dat...




Characteristics
 Data

independence is a form of database
management that keeps data separated
from all programs that make use of it.
 D...
It is the ability to change the internal
schema(Using new storage media, Using
different data structures, switching from o...
Logical data independence makes it
possible to change the structure of the
data(addition or deletion of fresh entities,
at...
It’s a collection of concepts, rules and
tools for the description of the structure
of the database.
Structure of the data...
The hierarchical data
model organizes data in
a tree structure
 each entity has only one
parent but can have
several chil...
In the network model,
entities are organized in
a graph, in which some
entities can be accessed
through several path
 The...




A
relational
database
allows the definition of
data structures, storage
and retrieval operations
and integrity const...
 Object-oriented

models
define a database as a
collection of objects
with
features
and
methods.
 information
is
represe...
Models, policies, rules or standards that
govern which data is collected, and how it is
stored, arranged, integrated, and ...




The highest level of
abstraction it define and
specify user views : views
that enable different data
users to see it...






The next-higher level of
abstraction describes what
data are stored in the
database,
and
what
relationships exist...







The
lowest
level
of
abstraction
It describes how the data will
be physically stored and
accessed, using a DBMS....
Database management systems
Database management systems
Database management systems
Database management systems
Upcoming SlideShare
Loading in...5
×

Database management systems

993

Published on

Database management systems (initiation)

Published in: Education, Technology
0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
993
On Slideshare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
84
Comments
0
Likes
3
Embeds 0
No embeds

No notes for slide

Database management systems

  1. 1.   Introduction Med.elhedhli@mailpost.tn Mohamed HEDHLY
  2. 2.  Presentation  Examples  Characteristics  Data independence • •  Data models • • • •  Physical independence Logical independence Hierarchical model Network model Relational model Object-oriented model Data architecture • • • External level Logical level Internal level
  3. 3.  Database management systems is a software package that allows users to create, edit, query, update and administrate Database  it also defines rules to validate and manipulate this data.  Using DBMS final users can simply store modify extract information from database.
  4. 4.   Characteristics
  5. 5.  Data independence is a form of database management that keeps data separated from all programs that make use of it.  Data cannot be redefined or reorganized by any of the programs that make use of it. In this manner, the data remains accessible, but it is also stable and cannot be corrupted by the applications
  6. 6. It is the ability to change the internal schema(Using new storage media, Using different data structures, switching from one access method to another, using different file organizations or storage structures, modifying indexes, ...) for reasons of optimization or reorganization without affecting the application programs.
  7. 7. Logical data independence makes it possible to change the structure of the data(addition or deletion of fresh entities, attributes or relationships... ) independently of modifying the applications or programs that make use of the data.
  8. 8. It’s a collection of concepts, rules and tools for the description of the structure of the database. Structure of the database means the data types, the data semantics, the constraints and the relationships for the description or storage of data respectively.
  9. 9. The hierarchical data model organizes data in a tree structure  each entity has only one parent but can have several children . At the top of hierarchy there is only one entity which is called Root. 
  10. 10. In the network model, entities are organized in a graph, in which some entities can be accessed through several path  The network model organizes data in a tree structure but allows each record to have multiple parent and child records 
  11. 11.   A relational database allows the definition of data structures, storage and retrieval operations and integrity constraints. the data and relations between them are organized in tables. A table is a collection of records and each record in a table contains the same fields.
  12. 12.  Object-oriented models define a database as a collection of objects with features and methods.  information is represented in the form of objects as used in object-oriented programming
  13. 13. Models, policies, rules or standards that govern which data is collected, and how it is stored, arranged, integrated, and put to use in data systems and in organizations The architecture of a database system determines its capability, reliability, effectiveness and efficiency in meeting user requirements. A database management system provides three views of the database data:
  14. 14.   The highest level of abstraction it define and specify user views : views that enable different data users to see it in different ways It also contains the method of deriving the objects in the external view from the objects in the conceptual view.
  15. 15.    The next-higher level of abstraction describes what data are stored in the database, and what relationships exist among those data. It defines how information is arranged within the database. the conceptual schema describes all relations that are stored in the database
  16. 16.     The lowest level of abstraction It describes how the data will be physically stored and accessed, using a DBMS. So it describes details of how data is stored: files, indices, etc. on the random access disk system. It also typically describes the record layout of files and type of files
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×