2004-01-27 - slide 1is 257 – spring 2004 information systems planning and the database design...

IS 257 – Spring 2004 2004-01-27 - SLIDE 1

Information Systems Planning and the Database

Design Process

Ray R. LarsonUniversity of California, Berkeley

School of Information Management and Systems

SIMS 257: Database Management

IS 257 – Spring 2004 2004-01-27 - SLIDE 2

Lecture Outline

• Review– Database Life Cycle

– Dive Shop DB

– Access

• Information Systems Planning

• Information Systems Architecture

• Information Engineering

• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 3

Announcements/ Review

• To get DiveShop database, download from Web– There are links from the announcements page at

http://sims.berkeley.edu/courses/is257/s04/

– There is an Access 2000 version there (if you have a very old copy of access we have an Access 97 version too).

• From the SIMS lab use IE to download – there appear to be problems using NetScape

• Today: Summation and calculations in Access• Today: Printing the query results

IS 257 – Spring 2004 2004-01-27 - SLIDE 4

Lecture Outline


– Dive Shop DB

– Access




• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 5

Database System Life Cycle

Growth,Change, &

Maintenance6

Operations5

Integration4

Design1

Conversion3

PhysicalCreation

2

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The “Cascade” View

Project Identifcation and Selection

ProjectInitiation

and Planning

Analysis

Logical Design

PhysicalDesign

Implementation

MaintenanceSee Hoffer, p. 41

IS 257 – Spring 2004 2004-01-27 - SLIDE 7

Another View of the Life Cycle

Operations5

Conversion3

PhysicalCreation

2Growth, Change

6

Integration4

Design1

IS 257 – Spring 2004 2004-01-27 - SLIDE 8

Lecture Outline


– Dive Shop DB

– Access




• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 9

Test Database

• The DiveShop database contains information for the business operations of a skin & scuba diving shop that:– Organizes trips to particular locations

(destinations) with various dive sites– Dive sites have various features including

• types of marine life found there• other features (like shipwrecks)

– Rents/Sells equipment to dive customers for particular trips.

IS 257 – Spring 2004 2004-01-27 - SLIDE 10

ER Diagrams

• Entity-Relationship Diagrams are one of the main tools for database design

• We will examine ER diagrams in greater detail later

• ER Diagrams show Entities (rectangles) and their attributes (ovals) and the relationships between entities (diamonds)

IS 257 – Spring 2004 2004-01-27 - SLIDE 11

DiveShop ER DiagramCustomer

No

ShipVia

Dest

Sites

BioSite

ShipVia

ShipWrck

BioLife DiveStok

DiveItem

DiveOrds

DiveCust

CustomerNo

ShipVia

OrderNo

OrderNo

ItemNo

ItemNo

DestinationName

Destination

SpeciesNo

Site No

Destinationno

Site No

Destinationno

SpeciesNo

Site No

1

1

1

1

1

1

1/n

1

1n

n

n

n

n

n

n

n

1

IS 257 – Spring 2004 2004-01-27 - SLIDE 12

Lecture Outline


– Dive Shop DB

– Access




• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 13

• Qualifying searches

• Doing calculations in searches

• Capturing results

IS 257 – Spring 2004 2004-01-27 - SLIDE 14

Lecture Outline


– Dive Shop DB

– Access




• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 15

Information Systems Planning

• Scope of IS is now the entire organization

• Sometimes called “enterprise-wide” computing

• Problem: isolated groups in an organization start their own databases and it becomes impossible to find out who has what information, where there are overlaps, and to assess the accuracy of the information

IS 257 – Spring 2004 2004-01-27 - SLIDE 16

Information Systems Planning

• To support enterprise-wide computing, there must be enterprise-wide information planning

• One framework for thinking about and planning for enterprise-wide computing is an Information Systems Architecture or ISA

• Most organizations do NOT have such an architecture

IS 257 – Spring 2004 2004-01-27 - SLIDE 17

Lecture Outline


– Dive Shop DB

– Access




• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 18

Information Systems Architecture

• An ISA is a “conceptual blueprint or plan that expresses the desired future structure for information systems in an organization”

• It provides a “context within which managers throughout the organization can make consistent decisions concerning their information systems”– Quotes from McFadden (Modern Database Management, 4th edition),

Ch. 3

IS 257 – Spring 2004 2004-01-27 - SLIDE 19


• Benefits of ISA:– “Provides a basis for strategic planning of IS– Provides a basis for communicating with top

management and a context for budget decisions concerning IS

– Provides a unifying concept for the various stakeholders in information systems.

– Communicates the overall direction for information technology and a context for decisions in this area

– Helps achieve information integration when systems are distributed (increasing important in a global economy)

– Provides a basis for evaluating technology options (for example, downsizing and distributed processing)”

IS 257 – Spring 2004 2004-01-27 - SLIDE 20


• Zachman ISA Framework components– Data

• The “what” of the information system– Process

• The “how” of the information system– Network

• The “where” of the information system– People

• Who performs processes and are the source and receiver of data and information.

– Events and Points in time• When processes are performed

– Reasons• For events and rules that govern processing

IS 257 – Spring 2004 2004-01-27 - SLIDE 21


• Six roles or perspectives of the Data, Process and Network components– Business scope (Owner)– Business model (Architect)– Information systems model (Designer)– Technology model (Builder)– Technology definition (Contractor)– Information system (User)

IS 257 – Spring 2004 2004-01-27 - SLIDE 22


Data Process Network

1. Business Scope(Owner)

List of entitiesimportant tothe business

List of functionsthe businessperforms

List of locations inwhich the businessoperates

IS 257 – Spring 2004 2004-01-27 - SLIDE 23



2. Business Model(Architect)

Business entities andtheir relationships

Function and processdecomposition Communications links

between business locations

IS 257 – Spring 2004 2004-01-27 - SLIDE 24



3. Information System Model(Designer)

Model of the businessdata and their relationships

Flows between application processes

Distribution Network

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4. Technology Model(Builder)

Database Design Process specifications Database Design

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5. Technology Definition(Contractor)

Database Schema and subschema definition

Program Code andcontrol blocks

Configurationdefinition

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6. Information System(User)

Database and information System

ConfigurationApplicationPrograms

IS 257 – Spring 2004 2004-01-27 - SLIDE 28

Lecture Outline


– Dive Shop DB

– Access




• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 29

Information Engineering

• A formal methodology that is used to create and maintain information systems

• Starts with the Business Model and works in a Top-Down fashion to build supporting data models and process models for that business model

IS 257 – Spring 2004 2004-01-27 - SLIDE 30

Information Engineering

Planning

Design

Analysis

Implementation

IS 257 – Spring 2004 2004-01-27 - SLIDE 31

Lecture Outline


– Dive Shop DB

– Access




• Database Design

IS 257 – Spring 2004 2004-01-27 - SLIDE 32

Database Design Process

ConceptualModel

LogicalModel

External Model

Conceptual requirements




Application 1

Application 1

Application 2 Application 3 Application 4

Application 2

Application 3

Application 4

External Model

External Model

External Model

Internal Model

IS 257 – Spring 2004 2004-01-27 - SLIDE 33

Stages in Database Design

• Requirements formulation and analysis

• Conceptual Design -- Conceptual Model

• Implementation Design -- Logical Model

• Physical Design --Physical Model

IS 257 – Spring 2004 2004-01-27 - SLIDE 34


• Requirements formulation and analysis– Purpose: Identify and describe the data that

are used by the organization– Results: Metadata identified, Data Dictionary,

Conceptual Model-- ER diagram

IS 257 – Spring 2004 2004-01-27 - SLIDE 35


• Requirements Formulation and analysis– Systems Analysis Process

• Examine all of the information sources used in existing applications

• Identify the characteristics of each data element– numeric– text– date/time– etc.

• Examine the tasks carried out using the information

• Examine results or reports created using the information

IS 257 – Spring 2004 2004-01-27 - SLIDE 36


• Conceptual Model– Merge the collective needs of all applications– Determine what Entities are being used

• Some object about which information is to maintained

– What are the Attributes of those entities?• Properties or characteristics of the entity• What attributes uniquely identify the entity

– What are the Relationships between entities• How the entities interact with each other?

IS 257 – Spring 2004 2004-01-27 - SLIDE 37


• Logical Model– How is each entity and relationship

represented in the Data Model of the DBMS• Hierarchic?• Network?• Relational?• Object-Oriented?

IS 257 – Spring 2004 2004-01-27 - SLIDE 38


• Physical (AKA Internal) Model– Choices of index file structure– Choices of data storage formats– Choices of disk layout

IS 257 – Spring 2004 2004-01-27 - SLIDE 39


• External Models– “User views” of the integrated database – Making the old (or updated) applications work

with the new database design

IS 257 – Spring 2004 2004-01-27 - SLIDE 40

Developing a Conceptual Model

• Overall view of the database that integrates all the needed information discovered during the requirements analysis.

• Elements of the Conceptual Model are represented by diagrams, Entity-Relationship or ER Diagrams, that show the meanings and relationships of those elements independent of any particular database systems or implementation details.

IS 257 – Spring 2004 2004-01-27 - SLIDE 41

Entity

• An Entity is an object in the real world (or even imaginary worlds) about which we want or need to maintain information– Persons (e.g.: customers in a business,

employees, authors)– Things (e.g.: purchase orders, meetings,

parts, companies)

Employee

IS 257 – Spring 2004 2004-01-27 - SLIDE 42

Attributes

• Attributes are the significant properties or characteristics of an entity that help identify it and provide the information needed to interact with it or use it. (This is the Metadata for the entities.)

Employee

Last

Middle

First

Name SSN

Age

Birthdate

Projects

IS 257 – Spring 2004 2004-01-27 - SLIDE 43

Relationships

• Relationships are the associations between entities. They can involve one or more entities and belong to particular relationship types

IS 257 – Spring 2004 2004-01-27 - SLIDE 44

Relationships

ClassAttendsStudent

PartSuppliesproject

partsSupplier

Project

IS 257 – Spring 2004 2004-01-27 - SLIDE 45

Types of Relationships

• Concerned only with cardinality of relationship

TruckAssignedEmployee

ProjectAssignedEmployee


1 1

n

n

1

m

Chen ER notation

IS 257 – Spring 2004 2004-01-27 - SLIDE 46

Other Notations




“Crow’s Foot”

IS 257 – Spring 2004 2004-01-27 - SLIDE 47

Other Notations




IDEFIX Notation

IS 257 – Spring 2004 2004-01-27 - SLIDE 48

More Complex Relationships

ProjectEvaluationEmployee

Manager

1/n/n

1/1/1

n/n/1

ProjectAssignedEmployee 4(2-10) 1

SSN ProjectDate

ManagesEmployee

Manages

Is Managed By

1

n

IS 257 – Spring 2004 2004-01-27 - SLIDE 49

Weak Entities

• Owe existence entirely to another entity

Order-lineContainsOrder

Invoice #

Part#

Rep#

QuantityInvoice#

IS 257 – Spring 2004 2004-01-27 - SLIDE 50

Supertype and Subtype Entities

ClerkIs one ofSales-rep

Invoice

Other

Employee

Sold

Manages

IS 257 – Spring 2004 2004-01-27 - SLIDE 51

Many to Many Relationships

Employee

ProjectIsAssigned

ProjectAssignment

Assigned

SSN

Proj#

SSN

Proj#Hours

IS 257 – Spring 2004 2004-01-27 - SLIDE 52

Next Time

• THURSDAY: – More on ER modelling– Designing the Conceptual Model for the

Diveshop Database

2004-01-27 - slide 1is 257 – spring 2004 information systems planning and the database design...

Documents

database management

n n n n n n n n

diveshop database

test database

database design process

systems sims

life cycle operations

various dive sites