1. Basic Definitions

2. A collection of incoming facts to the organization.
Basic Definitions
DATA
A collection of incoming facts to the organization.
DATA-ITEM NAME
The context for a recorded data-item is often indicated by a name,
such as date, name, age, etc.
Information
Incoming facts
Data processing
data
Output

3. Basic Definitions DATA-ITEM VALUE
It is the specific quantitative or qualitative values given to a specific data-item.
For example: If ‘AGE’ is an attribute of some entity and it is equal to ’22’, then 22 is the related data value and it is quantitative.
And if ‘CITY’ is an attribute of some entity and it is ‘Baghdad’ then ‘Baghdad’ represent the data item value for data-item name CITY, and it’s qualitative.

4. GROUP ITEMS AND ELEMENTRY ITEMS
Basic Definitions
GROUP ITEMS AND ELEMENTRY ITEMS
A group item is a collection of closely related items of information.
For example DATE usually has three parts, MONTH, DAY, YEAR, when any of there has no further subdivision into meaningful parts they are called ELEMENTRY data-item else the called GROUP data-item or (Aggregate).

5. An ENTITY Basic Definitions
Items about which we store information are referred to as Entities.
An Entity may be Tangible object such as:
A person (Employee), place (Amman), or thing (parts)
An Entity may be Intangible, such as:
An event (something happens at a particular time), customer-account, etc.

6. Basic Definitions AN ATTRIBUTE
An Entity has various properties which we may wish to record, so that we can recognize, remember, and describe it. These properties are called Attributes. For example:
Attributes of human being include items such as:
(height, weight, name, age, eye color, ets.)
Attributes of car accident include items such as:
(driver-name, time, location, cause of accident, ets.)

7. Basic Definitions
RECORD
Is a collection of related data-item which share a common context about a particular entity.
FILE
A file may be defined as a set of (Logical) records all of which related to a particular area of interest.

8. Basic Definitions
ENTITY IDENTIFIER
It is necessary for the programmer or data administrator to be able to refer to a record relating to a given entity, and it is necessary for the computer to be able to identify it and to have a means of finding it in the storage unit. For this purpose one of the attributes is usually designated an entity identifier.

9. Basic Definitions ENTITY IDENTIFIER
It is necessary for the programmer or data administrator to be able to refer to a record relating to a given entity, and it is necessary for the computer to be able to identify it and have a means of finding it in the storage unit. For this purpose one of the attributes is usually designated an entity identifier.
For example the entity identifier of an employee would be
EMPLOYEE-NUMBER.
And the entity identifier of an account record would be the
ACCOUNT-NUMBER.
Some time more than attribute is required in order to identify a record.
For example, to identify an airline flight record the FLIGHT-NUMBER
and FLIGHT-DATE are needed.

10. Basic Definitions
KEY
Is an attribute or a set of attributes which the computer uses to identify a record.
PRIMARY KEY
Is defined as that key used to uniquely identify one record. Such as ‘STUDENT-NUMBER’, ‘EMPLOYEE-ID’, etc.

11. Basic Definitions CUSTOMER table Customer-id Customer-name
Customer-street
Customer-city
192-83
Ahmed
23 Alma St.
Jbeha
182-74
Kasim
12 Main St.
Sweleh
Rana
7 Park Ave.
Marka
Susan
57 North St.
Jabal
Tarik
33 Alma St.
Ali
88 East St.
Gardens
Data-item name
(Attributes)
(Fields)

12. Basic Definitions CUSTOMER table Customer-id Customer-name
Customer-street
Customer-city
192-83
Ahmed
23 Alma St.
Jbeha
182-74
Kasim
12 Main St.
Sweleh
Rana
7 Park Ave.
Marka
Susan
57 North St.
Jabal
Tarik
33 Alma St.
Ali
88 East St.
Gardens
Data-item name
Data-item value

13. Basic Definitions CUSTOMER table Customer-id Customer-name
Customer-street
Customer-city
192-83
Ahmed
23 Alma St.
Jbeha
182-74
Kasim
12 Main St.
Sweleh
Rana
7 Park Ave.
Marka
Susan
57 North St.
Jabal
Tarik
33 Alma St.
Ali
88 East St.
Gardens
Primary key

14. Basic Definitions CUSTOMER table Records . . Customer File Customer-id
Customer-name
Customer-street
Customer-city
192-83
Ahmed
23 Alma St.
Jbeha
182-74
Kasim
12 Main St.
Sweleh
Rana
7 Park Ave.
Marka
Susan
57 North St.
Jabal
Tarik
33 Alma St.
Ali
88 East St.
Gardens
Records . .
Customer File

15. END