Elements of Database System

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Elements of Database System

• In this Chapter we will Examine
• The Relationships among three Elements
• People
• Software
• Technique
• And how the database approach may be used to
  develop systems that effectively support
  organizational needs
• How to design and structure effective DB System

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Elements of Database Systems

• Structure
• Refer to the parts of system and how these part
  interact
• The concern is with blending the five elements
  into a database system that serve the need of the
  organization.
• After this chapter you should understand how
  hardware, software, people, procedures, and plans
  can be blended to form an effective database
  system

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Elements of Database System

• How a Database System is like a Campus
• When campus or new building is planned
• This plan takes into consideration
• The special needs
• The special characteristics of the site
• Land is valuable commodity, so it use is
  carefully planned
• Data however, may not be recognized as a valuable
  resource, and often little planning

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The Need for Planning Modular Design

• Database should be compatible with all
  organizational units.
• Because this can lead to expensive redundancy and
  difficult to maintain
• Think about a building links between building
  walls, and whole structure.
• And they serve the need of the community

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The Need for Planning Modular Design

• A well designed database system consist of
• Modules
• Is used to describe a major element of the
  overall database system. DBS are loosely coupled
  and may be built independently, but they should
  fit into a grander scheme described in DB Master
  plan.
• DBSMP lays out the ultimate structure and
  contents of the database system
• Subsystems
• Of a database system contain data about entities,
  such as customers and products

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The need for planning Modular design

• Entity
• Is any object, tangible, or intangible, about
  which the organization wishes to store data.
• Entities have attributes such as name, color,
  price
• Entities and attributes must be accessible
  through some way
• The way is called navigation path
• Arrows in database are pointers indicating where
  the programe should look on the systems storage
  device to find record

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Database system
Marketing module
Personal Mgmt module
Personal database
Mkt database
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The Need for Access, Security, Adaptability

• If a building is poorly designed then is that
  easy to access and so on
• Someone may be break the building and steal
  something
• If it is constructed then it shouldnt be so
  expensive to put new things init.
• So good Database system design is to develop a
  DBMP

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DB System Master Plan

• Suggested outline for DBMP
• Organizational environment
• Goals and objective
• Organizational structure function
• Elements of the database
• A major entities and relationship
• Entity groups
• Modules
• User groups
• Costs and benefits
• Implementation schedule
• Summary

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DBMS consider

• Two aspects are important
• Organizational goals and objective
• The manner in which the enterprise is structured
• Assist the managers of organizations in measuring
  the level of goal attainment and in steering the
  organization towards its goals

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Entity Charts

• Purpose of DBMSMP is to guide
• Organization to manage its information resources
  effectively.
• Information needs at every level of organization
• It should identify the major information users
  and their needs.
• It should specify the entities to be contained in
  DB and relation between them.
• Specified entities and relationships can be
  illustrated in diagram

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Entity Chart for institute
course
Instructor
Participant
Evaluation
Prospect
Organization
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Entity chart for institute

• Entities of interest were
• Course
• Instructors
• Participants
• Course evaluation
• Prospects
• And organization for which prospects work

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Entity chart

• Relationship in the diagram are of three types
• One-to-one
• One-to-many
• Many-to-many
• Details are as..

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Entity chart

• One to one
• One instance of an entity of a given type is
  associated with only one member of another type
  such as, a participant in a course fills out one
  evaluation form for the course. Conversely, a
  given evaluation form was prepared by one
  participant

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Entity chart

• One to many
• One instance of a given type of entity is related
  to many instance of another type. Such as one
  prospects work for one organization, so the line
  emanating from prospect has a single arrowhead
  where it terminates with organization. But one
  organization may have several prospects for a
  given course.

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Entity chart

• Many to many
• Relationship is one in which many entities for
  one type are associated with many instance of
  another type. Such as, an instructor may teach
  many different courses, and one course may be
  taught by many different instructors.

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Entity Groups

• Large and complex DBS can not be designed and
  build at once.
• So it should be done piece by piece.
• The Master plan should describe the major pieces
  and or modules of the system to be developed
• How they will work together
• Structure, relationship and development of it

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Costs and Benefits

• Investment they can pay for DBS
• Cost of development
• Expensive to develop
• Could be uncertainty for cost and time
• Value of the benefits of DBS are more difficult
  to estimate than cost

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• Thanks very much!!
• Any Questions????????