2006.09.05 - SLIDE 1IS 257 - Fall 2006 Information Systems Planning and the Database Design Process...
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Transcript of 2006.09.05 - SLIDE 1IS 257 - Fall 2006 Information Systems Planning and the Database Design Process...
IS 257 - Fall 2006 2006.09.05 - SLIDE 1
Information Systems Planning and the Database
Design Process
Ray R. Larson
University of California, Berkeley
School of Information
IS 257: Database Management
IS 257 - Fall 2006 2006.09.05 - SLIDE 2
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - SLIDE 3
Announcements/ Review
• To get DiveShop database, download from Web– There are links from the announcements page
at http://ischool.berkeley.edu/courses/is257/f06/
• Today: Summation and calculations in Access
• Today: Printing the query results
IS 257 - Fall 2006 2006.09.05 - SLIDE 4
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - SLIDE 5
Database System Life Cycle
Growth,Change, &
Maintenance6
Operations5
Integration4
Design1
Conversion3
PhysicalCreation
2
IS 257 - Fall 2006 2006.09.05 - SLIDE 6
The “Cascade” View
Project Identifcation and Selection
ProjectInitiation
and Planning
Analysis
Logical Design
PhysicalDesign
Implementation
MaintenanceSee Hoffer, p. 41
IS 257 - Fall 2006 2006.09.05 - SLIDE 7
Another View of the Life Cycle
Operations5
Conversion3
PhysicalCreation
2Growth, Change
6
Integration4
Design1
IS 257 - Fall 2006 2006.09.05 - SLIDE 8
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - 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 - Fall 2006 2006.09.05 - 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 - Fall 2006 2006.09.05 - 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 - Fall 2006 2006.09.05 - SLIDE 12
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - SLIDE 13
Access search operations
• Qualifying searches
• Doing calculations in searches (and aggregate functions)
• Capturing results
IS 257 - Fall 2006 2006.09.05 - SLIDE 14
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - SLIDE 15
Information Systems Planning
• Scope of IS is now the entire organization
• Sometimes called “enterprise-wide” computing or “Information Architecture”
• 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 - Fall 2006 2006.09.05 - 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 - Fall 2006 2006.09.05 - SLIDE 17
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - 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 - Fall 2006 2006.09.05 - SLIDE 19
Information Systems Architecture
• 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)”
– Quotes from McFadden (Modern Database Management, 4 th edition), Ch. 3
IS 257 - Fall 2006 2006.09.05 - SLIDE 20
Information Systems Architecture
• 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• Why: For events and rules that govern processing
IS 257 - Fall 2006 2006.09.05 - SLIDE 21
Information Systems Architecture
• 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 - Fall 2006 2006.09.05 - SLIDE 22
Zachman Framework
IS 257 - Fall 2006 2006.09.05 - SLIDE 23
Information Systems Architecture
Data Process Network
1. Enterprise Scope(Owner)
List of entitiesimportant tothe business
List of processesor functions thatthe businessperforms
List of locations inwhich the businessoperates
IS 257 - Fall 2006 2006.09.05 - SLIDE 24
Information Systems Architecture
Data Process Network
2. Enterprise Model(Architect)
Business entities andtheir relationships
Function and processdecomposition Communications links
between business locations
IS 257 - Fall 2006 2006.09.05 - SLIDE 25
Information Systems Architecture
Data Process Network
3. Information System Model(Designer)
Model of the businessdata and their relationships (ERD in Database design)
Flows between application processes
Distribution Network
IS 257 - Fall 2006 2006.09.05 - SLIDE 26
Information Systems Architecture
Data Process Network
4. Technology Constrained Model(Builder)
Database Design (logical) Process specifications Database Design
IS 257 - Fall 2006 2006.09.05 - SLIDE 27
Information Systems Architecture
Data Process Network
5. Technology Definition/Detailed Representations
(Contractor)
Database Schema and subschema definition
Program Code andcontrol blocks
Configurationdefinition/ NetworkArchitecture
IS 257 - Fall 2006 2006.09.05 - SLIDE 28
Information Systems Architecture
Data Process Network
6. Functioning Enterprise(User)
ImplementedDatabase and information
CurrentSystemConfiguration
ImplementedApplicationPrograms
IS 257 - Fall 2006 2006.09.05 - SLIDE 29
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - SLIDE 30
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 - Fall 2006 2006.09.05 - SLIDE 31
Information Engineering
Planning
Design
Analysis
Implementation
IS 257 - Fall 2006 2006.09.05 - SLIDE 32
Lecture Outline
• Review– Database Life Cycle
– Dive Shop DB
– Access
• Information Systems Planning
• Information Systems Architecture
• Information Engineering
• Database Design
IS 257 - Fall 2006 2006.09.05 - SLIDE 33
Database Design Process
ConceptualModel
LogicalModel
External Model
Conceptual requirements
Conceptual requirements
Conceptual requirements
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 - Fall 2006 2006.09.05 - SLIDE 34
Stages in Database Design
• Requirements formulation and analysis
• Conceptual Design -- Conceptual Model
• Implementation Design -- Logical Model
• Physical Design --Physical Model
IS 257 - Fall 2006 2006.09.05 - SLIDE 35
Database Design Process
• 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 - Fall 2006 2006.09.05 - SLIDE 36
Database Design Process
• 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 - Fall 2006 2006.09.05 - SLIDE 37
Database Design Process
• 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 - Fall 2006 2006.09.05 - SLIDE 38
Database Design Process
• Logical Model– How is each entity and relationship
represented in the Data Model of the DBMS• Hierarchic?• Network?• Relational?• Object-Oriented?
IS 257 - Fall 2006 2006.09.05 - SLIDE 39
Database Design Process
• Physical (AKA Internal) Model– Choices of index file structure– Choices of data storage formats– Choices of disk layout
IS 257 - Fall 2006 2006.09.05 - SLIDE 40
Database Design Process
• External Model– User views of the integrated database – Making the old (or updated) applications work
with the new database design
IS 257 - Fall 2006 2006.09.05 - SLIDE 41
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 - Fall 2006 2006.09.05 - SLIDE 42
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 - Fall 2006 2006.09.05 - SLIDE 43
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 - Fall 2006 2006.09.05 - SLIDE 44
Relationships
• Relationships are the associations between entities. They can involve one or more entities and belong to particular relationship types
IS 257 - Fall 2006 2006.09.05 - SLIDE 45
Relationships
ClassAttendsStudent
PartSuppliesproject
partsSupplier
Project
IS 257 - Fall 2006 2006.09.05 - SLIDE 46
Types of Relationships
• Concerned only with cardinality of relationship
TruckAssignedEmployee
ProjectAssignedEmployee
ProjectAssignedEmployee
1 1
n
n
1
m
Chen ER notation
IS 257 - Fall 2006 2006.09.05 - SLIDE 47
Other Notations
TruckAssignedEmployee
ProjectAssignedEmployee
ProjectAssignedEmployee
“Crow’s Foot”
IS 257 - Fall 2006 2006.09.05 - SLIDE 48
Other Notations
TruckAssignedEmployee
ProjectAssignedEmployee
ProjectAssignedEmployee
IDEFIX Notation
IS 257 - Fall 2006 2006.09.05 - SLIDE 49
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 - Fall 2006 2006.09.05 - SLIDE 50
Weak Entities
• Owe existence entirely to another entity
Order-lineContainsOrder
Invoice #
Part#
Rep#
QuantityInvoice#
IS 257 - Fall 2006 2006.09.05 - SLIDE 51
Supertype and Subtype Entities
ClerkIs one ofSales-rep
Invoice
Other
Employee
Sold
Manages
IS 257 - Fall 2006 2006.09.05 - SLIDE 52
Many to Many Relationships
Employee
ProjectIsAssigned
ProjectAssignment
Assigned
SSN
Proj#
SSN
Proj#Hours
IS 257 - Fall 2006 2006.09.05 - SLIDE 53
Next Time
• THURSDAY: – More on ER modelling– Designing the Conceptual Model for the
Diveshop Database