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Basic Definitions

Fundamentals of Data Base

Dr. Rashid Al_Zubaidy

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Basic Definitions

Welcome: The first learning sequence “ Basic Definitions “

Present learning: We shall explore the following definitions:

- Data-item name and value. - Key identifier. - Record and File.

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Basic Definitions

DATA

A collection of incoming facts to the organization.

Incoming facts data

Data processing

InformationOutput

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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.

Incoming facts data

Data processing

InformationOutput

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Basic Definitions

GROUP ITEMS AND ELEMENTRY ITEMS

A group item is a collection of closely related items of information.

For example DATE usually have three parts, MONTH, DAY, YEAR, when any of there have no farther subdivision into meaning full parts they are called ELEMENTRY data-item else the called GROUP data-item or (Aggregate).

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Basic Definitions

An ENTITYItems 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 Non Tangible, such as:

An event (something happens at a particular time), customer-account, etc.

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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.)

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Basic Definitions

DATA-ITEM VALUE It is the specific quantitive or qualitive 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 quantitive.

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 qualitive.

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Basic Definitions

RECORD

Is a collection of related data-item which share a common context about a particular entity.

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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.

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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.

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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.

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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.

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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.

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Basic Definitions

KEYIs an attribute or a set of attributes which the

computer uses to identify a record.

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Basic Definitions

KEYIs 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’, ets.

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Basic Definitions

KEYIs 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’, ets.

SECONDARY KEYIs a key which does not identify a unique record but which

identifies all those which have certain property.

Such as ‘DEPARTMENT-NAME’, ‘SKILL-CODE’, ets.

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Basic Definitions

Customer-id Customer-name

Customer-street

Customer-city

192-83 Ahmed 23 Alma St.

Jbeha

182-74 Kasim 12 Main St.

Sweleh

677-600 Rana 7 Park Ave.

Marka

321-140 Susan 57 North St.

Jabal

710-569 Tarik 33 Alma St.

Jbeha

210-872 Ali 88 East St. Gardens

CUSTOMER table

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Basic Definitions

Customer-id Customer-name

Customer-street

Customer-city

192-83 Ahmed 23 Alma St.

Jbeha

182-74 Kasim 12 Main St.

Sweleh

677-600 Rana 7 Park Ave.

Marka

321-140 Susan 57 North St.

Jabal

710-569 Tarik 33 Alma St.

Jbeha

210-872 Ali 88 East St. Gardens

CUSTOMER table

Data-item name

(Attributes)

(Fields)

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Basic Definitions

Customer-id Customer-name

Customer-street

Customer-city

192-83 Ahmed 23 Alma St.

Jbeha

182-74 Kasim 12 Main St.

Sweleh

677-600 Rana 7 Park Ave.

Marka

321-140 Susan 57 North St.

Jabal

710-569 Tarik 33 Alma St.

Jbeha

210-872 Ali 88 East St. Gardens

CUSTOMER table

Data-item name

Data-item value

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Basic Definitions

Customer-id Customer-name

Customer-street

Customer-city

192-83 Ahmed 23 Alma St.

Jbeha

182-74 Kasim 12 Main St.

Sweleh

677-600 Rana 7 Park Ave.

Marka

321-140 Susan 57 North St.

Jabal

710-569 Tarik 33 Alma St.

Jbeha

210-872 Ali 88 East St. Gardens

CUSTOMER table

Primary key

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Basic Definitions

Customer-id Customer-name

Customer-street

Customer-city

192-83 Ahmed 23 Alma St.

Jbeha

182-74 Kasim 12 Main St.

Sweleh

677-600 Rana 7 Park Ave.

Marka

321-140 Susan 57 North St.

Jabal

710-569 Tarik 33 Alma St.

Jbeha

210-872 Ali 88 East St. Gardens

CUSTOMER table

Primary key

Secondary key

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Basic Definitions

Customer-id Customer-name

Customer-street

Customer-city

192-83 Ahmed 23 Alma St.

Jbeha

182-74 Kasim 12 Main St.

Sweleh

677-600 Rana 7 Park Ave.

Marka

321-140 Susan 57 North St.

Jabal

710-569 Tarik 33 Alma St.

Jbeha

210-872 Ali 88 East St. Gardens

CUSTOMER table

Customer File

.

.

Reco

rds

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Basic Definitions

Summary: In this learning sequence, we discussed

the basic definitions related the subject “ Data Base “.

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Basic Definitions

END