ENJOY THE DATABASE LESSON

DEFINITION OF DATABASE

The termDATA BASE means: The collection of information that is organized so that it can easily be accessble, managed and updated with the aim of reducing the Repetition of data.

APPLICATION OF DATA BASE

DATA BASE CAN BE USING IN BANKING for all transactions done in Banking.

IT can be also be applied in TRAVELS;SCHOOLS, SALES, MANIFUCTURING, HUMAN RESOURCES, Etc.

DEFINITIONN OF CLIENT SERVER

THE CLIENT SERVER is a system that enables the share of the information on the network.

IMPORTANCE OF STUDYING DATA BASE

DATA INDEPENDENT

This is form of database management that keeps data separate from the programs that use the database.

TYPES OF DATA INDEPENDENT

LOGICAL INDEPENDENCE

This is the ability of changing the database logical schema without changing external schema.

PHYSICAL INDEPENDENCE

This is the ability of changing the DATA BASE physical schema whithout changing the logical schema.

DATA ACCESS

DATA ACCESS refers to softwares and activities related to storing and retrieving and creating the DATA BASE.

CONCURANT TRANSACTIONS

In CONCURENT TRANSACTIONS each use works as he/she is the one who is using the system.

DATA INTEGRITY AND SAFETYS

DATA INTEGRITY Is the assurance that the data will always be CORRECT, CONSISTANT AND ACCESSIBLE..

DATA SECURITY

This is the protection of the data from being damaged

REDUCTION OF THE DUPLICATION OF THE DATA

This is a system of reducing the repetition of the data

DATA RECOVERY AFTER BREAKDOWN

This is a process of getting back the data after being damaged so that they can be accessible again.

DATA INCONSISTENCY

Damage of data affects virtually all application programs.

LEVELS OF DESIGNING A DATA BASE

THE CONCEPTUAL LEVEL

conceptual level makes it possible to concieve a base of data. we choose to use model ENTITIES, PROPERTY, IDENTIFIER, ASSOCIATION, CARDINALITIES and ROLE Etc. This presents the data in tables

THE LOGICAL LEVEL ALSO KNOWN AS ORGANIZATION MODEL

Logical level makes it possible to create relation structures enables us into practice to put the conceptualization by imagining the relational Data Base Management System DBMS

the physical level also known as operational level

Consists in making the establishment or the practical application of all the proceding theories by using a data processing tool (software) to establish our data base.

CONCEPTS RELATING TO THE LEVELS OF DESIGNING A DATABASE

PROPERTY

Property is a smallest unit of information that is handled by the designer or user. it is atomic, and it is not decomposable.

characteristics of a property.

Property is characterized by property name, atomic, description, data type.

ENTITY alson know as a TABLE

Entity is a set of propeties. property name, data type and description.

EDENTIFIER

Among all the properties one or more of them must play a particular role that allow to distinguish each occurence from the others. The property which does this is known as Identifier. This kind of property is like the president who went outside of his or her country. when you're going to create a foreigner key, it is like the ambassadors who are in different countries.

TYPE OF IDENTIFIER

Simple identifier

Simple Identifier: This is when a an ENTITY has one primary key which Identifies the others.