cse3180 semester 1 2005 week 2 / 1 lecture no. 2 project planning / management database design...
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CSE3180 Semester 1 2005 week 2 / 1
Lecture No. 2Lecture No. 2
Project Planning / ManagementDatabase Design
Entities, Relationships, Modelling
CSE3180 Semester 1 2005 week 2 / 2
Important DatesImportant Dates
Wednesday 16th March :
Semester 1 ‘Enrolment Statement’ issued to all students
CSE3180 Semester 1 2005 week 2 / 3
Data Base PrinciplesData Base Principles
This Lecture’s Objectives:
1. To briefly look at some Project Planning activities
2. To further develop aspects of Database Design
3. To introduce you to Entities and Entity relationships
4. To work through some examples of E-R modelling
CSE3180 Semester 1 2005 week 2 / 4
Project PlanningProject Planning
• Planning• Scheduling• Cost Tracking• Resource Management• Reporting
Software FunctionsReal time interactive operationAdd / Delete itemsChange logic dependencies
Adjust calendar and calendar dependenciesChange resource and availability levels and datesMouse driven : Multiple platforms
(Microsoft, MacIntosh)
CSE3180 Semester 1 2005 week 2 / 5
Project PlanningProject Planning
1. Project Manager’s Controls - Schedule
- Costs
- Technical
- Resources
2. Goals, Objectives, Targets, Disciplines
3. Development of Project Definition / Scope
4. Performance Assessment Criteria
5. Level of Detail in Planning
6. Feed back and Controls
7. Replanning and Rescheduling
8. Budgeting
CSE3180 Semester 1 2005 week 2 / 6
Project PlanningProject Planning
Task / Week 1 2 3 4 5 6 7Analysis
Design
Review
Programming
Implementation
- Plan
- Manuals
System Testing
Review
Acceptance Test
Review Results
Handover
CSE3180 Semester 1 2005 week 2 / 7
PERT DiagramPERT Diagram
start
Get Mix Pour intoingredients Ingredients cake pan
Preheatoven
Place Bake Removecake in cake cake fromoven oven
CSE3180 Semester 1 2005 week 2 / 8
Your ProjectYour Project
Why did we divert into Project Planning ?
Your assignment is a project, and the resources (you skills, your time, computer time and the preparation of the various deliverables need to be carefully managed.
One of the team will need to take the role of Co-ordinator, and one (not necessarily the same person) will need to take the role of Quality Controller and Reviewer - i.e. to critically review what the team have done or are intending to do.
One person will be the minute taker of your meetings, and there will probably be the recognition of individual skills
(e.g. screen design)
CSE3180 Semester 1 2005 week 2 / 9
Data Base DesignData Base Design
CSE3180 Semester 1 2005 week 2 / 10
Data Base DesignData Base Design
· Reduce data redundancy.
· Provide stable data structures that can be readily changed with changing user requirements.
· Allow users to make ad hoc requests for data.
· Maintain complex relationships between data elements.
· Support a large variety of decision needs
CSE3180 Semester 1 2005 week 2 / 11
End Product of Data Base DesignEnd Product of Data Base Design
A database which will:
• Accurately reflect the ‘real world’ data in all required aspects
• Be responsive to Management Information demands
• Reflect Business Rules and Controls
• Be capable of modification to meet changes in Management needs
• Be an asset to the Organisation/Enterprise
CSE3180 Semester 1 2005 week 2 / 12
Business Functions and ProcessesBusiness Functions and Processes
• Business Functions :
Broad groups of closely related activities and decisions which contribute to a product or service like cycle. (e.g. planning, materials management, production planning, quality assurance).
CSE3180 Semester 1 2005 week 2 / 13
Business Functions and ProcessesBusiness Functions and Processes
• Business Processes : Decision related activities which occur within a function. They are related to management of people, money, material and information.
• Materials Management (Business Function)could be
subdivided into: requirements planning, purchasing, goods
received, material accounting, stock-keeping
Business Processes should reflect related activity groupings
CSE3180 Semester 1 2005 week 2 / 14
Business ActivitiesBusiness Activities
Business Activities : Specific operations or transactions
required to carry out a process
Some guidelines:
An activity should produce some clearly defined (identifiable) result - a product, a decision, a plan ......
An activity has clear boundaries - a clear beginning and end. Activities do not overlap.
An activity is carried out as a unit, by a single agent or a team
Once initiated, an activity proceeds independently of and from other activities.
CSE3180 Semester 1 2005 week 2 / 15
Business EntitiesBusiness Entities
Are persons, objects or events about which Information is, or will be, recorded in the Information Data Base
Many of these Entities can be identified with Business Activities (e.g. supplier , purchase order , customer)
(notice the use of the singular noun - there is no particular standard)
CSE3180 Semester 1 2005 week 2 / 16
Critical Success FactorsCritical Success Factors
* Key factors which must be performed well to ensure the success of an organisation
* Also known as Critical Performance Items CPI
and Key Performance Indicators KPI
e.g. production failure rate < 0.01% of total production units
production cost increases <= c.p.i. increases
customer service complaints < 1% of all customer transactions
absenteeism < 1% of staff in any 24 hour period
product quality => advertised standards (water, power)
no more than 1% of trains > 3 late at destination
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Design CriteriaDesign Criteria
- data availability
- data reliability
- data currency
- data consistency
- data flexibility
- data efficiency
Verify these criteria are satisfied via technical review
CSE3180 Semester 1 2005 week 2 / 18
Database DesignDatabase Design
- the process of developing database structures from user information requirements
- a structured methodology
Structured Methodology - a number of ordered formalprocesses with known inputs and expected outputs
Objectives
1. derive relationships2. evolve to meet user requirements3. user requests are met within reasonable time limits
CSE3180 Semester 1 2005 week 2 / 19
3 Schema Architecture3 Schema Architecture
The Primary Objectives of a DBMS are to providefacilities for :
1. Definition of Database Logical Structures
2. Definition of Physical Structures
3. Access to the Database
4. Definition of Storage Structures to store user data
These components are known as the ‘database architecture’
CSE3180 Semester 1 2005 week 2 / 20
3 Schema Architecture3 Schema Architecture
EXTERNALSCHEMAS
CONCEPTUALSCHEMA
INTERNALSCHEMA(Storage Views)
user 1 user 2 user..nlogical
logical
physical
(as seen by database analysts, designers, programmers and the Data Base Administrator)
(as seen by the Operating System and the Data Base Administrator)
SCHEMA: Describes data in the data base - also sub-schema
Global
CSE3180 Semester 1 2005 week 2 / 21
3 Schema Architecture3 Schema Architectureexternal external external external view A view B view C view X Cobol C Assembler External+ DML + DML DML + DML Schemas
dbms Conceptual Model Conceptual Schema
Internal Model Internal Schema
Physical Level
userinterface
logicalrecord
interface
storedrecord
interface
physicalrecord
interface
operatingsystem
CSE3180 Semester 1 2005 week 2 / 22
Progression StagesProgression Stages
The previous overhead gave the foundation for the stages of design
Stage 1: The Conceptual Design (External Schemas) - the recognition and understanding of user requirements.
The purpose of this stage, which is independent of any / all physical considerations, is to construct a model of the information used in an organisation or business
Data flow diagrams, data structure diagrams are the ‘tools’
CSE3180 Semester 1 2005 week 2 / 23
Progression StagesProgression Stages
Stage 2 : Logical Database Design
This is the stage where a model is constructed of the information used in an organisation
The model is a specific model (E-R Diagram, UML, O-O model) but is independent of any DBMS
Stage 3 : Physical Database Design
This describes the base relations, file organisations, indexes, integrity constraints and security. It is tailored to a specific DBMS
CSE3180 Semester 1 2005 week 2 / 24
Database DesignDatabase Design
FunctionalRequirements
Information LevelDesign Processes
Final InformationLevel Design
PhysicalConstraints
PhysicalLevel Design
Final DatabaseStructure
Other mattersDomains, Nulls, Derived Data,Encoded Data.
Data Base Model
CSE3180 Semester 1 2005 week 2 / 25
Database DesignDatabase Design
4th Generation Environment - User Perception
user terminal
teleprocessing report query electronicmonitor writer language mail
applicationprograms
data dictionaryDBMS
database
structured and non-structured dataimages, graphics, video,voice
CSE3180 Semester 1 2005 week 2 / 26
Data ModellingData Modelling
Data Modelling is about - Structuring and Organising Data
Leads to the emergence of Records Attributes Data Types Constraints Semantics e.g. age relates to ? person ? building ? isotope ? galaxy ?
Commercial Data Base ModelsHierarchical Specific organisation and relationships between records held in the databaseNetwork Relational Constraints, domains, conditions of update, inserts, deletes, modifications, access
CSE3180 Semester 1 2005 week 2 / 27
EntitiesEntities
• The designation of a ‘thing’ about which data is to be collected
stored
processed
• Typical Entities : person , item , building , stock ,
vehicle , job , book , library
CSE3180 Semester 1 2005 week 2 / 28
Entity Relationship DiagramsEntity Relationship Diagrams
Used to model relationships
1 to 1 relation 1:11 to Many 1:MMany to Many M:N (real world situations)
vehicle regn no
department staff
supplier item
1:1
1:M
M:N
Also :-OptionalMandatoryoccurrence
CSE3180 Semester 1 2005 week 2 / 29
Entity RelationshipsEntity Relationships
One to One
One to Many
Many to One
Many to Many
CSE3180 Semester 1 2005 week 2 / 30
Logical Data ModellingLogical Data Modelling
• 3 types of data objects:– Entities– Attributes– Relationships
• Entities: Are persons, places, or things about which data is to be, or is, gathered
• Attributes : Are the properties of entities
Examples are Names, Tax Numbers, Age, Status• Relationships : Describe how entities relate to each other
e.g. Customers BUY Products
Persons WORK ON Jobs
CSE3180 Semester 1 2005 week 2 / 31
Logical Data ModellingLogical Data Modelling
Entity-Type : An entity type represents the class of Objects which share some common aspect -
such as Jobs, Persons, Materials, Houses
Entity-Occurrence : Also called ‘entity instance’
Example : “3 bedroom, brick veneer, 10 years old” are some of the actual values of an
entity instance of the Entity Type ‘House’
CSE3180 Semester 1 2005 week 2 / 32
Logical Data ModellingLogical Data Modelling
CARDINALITY
Premise: If an entity ‘A’ relates to another entity ‘B’, then the conditions of occurrences of ‘A’ and ‘B’ need to be known.
Cardinality : The specification of the number of occurrences of 1 entity type which can be related to the
number of occurrences of another entity type
Cardinality is expressed as ‘one’ or ‘many’
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Logical Data ModellingLogical Data Modelling
2 entities can be related as :
One to One : (1 : 1)
The interpretation of this is that an occurrence of an entity ‘A’ can relate to ONE and ONLY ONE occurrence of entity ‘B’, and an occurrence of entity ‘B’ can relate to ONE and ONLY ONE occurrence of entity ‘A’
One to Many : (1: M) or (1 : N)
The interpretation is that ONE occurrence of entity ‘A’ can relate to ONE or MORE occurrences of entity ‘B’, but an occurrence of entity ‘B’ can relate to ONE ONLY occurrence of entity ‘A’
CSE3180 Semester 1 2005 week 2 / 34
Logical Data ModellingLogical Data Modelling
Many to Many (M : N) - a common business relationship
The interpretation is that ONE or MORE occurrences of entity ‘A’ can relate to ONE or MORE occurrences of entity ‘B’ and ONE or MORE occurrences of entity ‘B’ can relate to ONE or MORE occurrences of entity ‘A’
CSE3180 Semester 1 2005 week 2 / 35
Logical Data ModellingLogical Data Modelling
MODALITY
An extension of relationship
Indicates whether an occurrence MUST PARTICIPATE in a relationship
Cardinality indicates the maximum number of entity occurrences which can participate in a relationship
Modality indicates the minimum number of occurrences
Modality = 0 if an occurrence is not needed or is optional
Modality = 1 if an entity occurrence is required or mandatory
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Logical Data ModellingLogical Data Modelling
DEGREE
Relates to the number of entity types associated in a relationship
UNARY - The entity type is related only to itself (also called recursive)
BINARY - Two entity types are related (most common case)
TERNARY - A relationship involving more than two entity types
CSE3180 Semester 1 2005 week 2 / 37
Logical Data ModellingLogical Data Modelling
ATTRIBUTE TYPES and ATTRIBUTE VALUES
An attribute type is an occurrence of a named set of values
e.g. ‘size’, ‘name’, ‘mass’, ‘person_id’
An attribute value is an occurrence (or instance) of an attribute type
An attribute value is a characteristic of, or a fact about an entity occurrence
e.g. Attribute ‘size’ Attribute value ‘25.4mm’
Entities/Attributes are often referred to as ‘meta-data’, that is ‘data about data values’
CSE3180 Semester 1 2005 week 2 / 38
Logical Data ModellingLogical Data Modelling
DOMAINSA ‘Domain’ is a set of possible values which an attribute set can
adopte.g. dates, integers, person name constructions, post codes
3 Main Types of Domains:Data Type : Numeric, Text, Integer, Date .....Ranges : Values between sets
‘Employee IDs must be between 10156 and 10987’
Acceptable Values : Specific Post Codes, Area Codes, Names of Prominent People, Building
Names They indicate the only values an attribute can have. All of these features contribute to ‘Database Integrity’
CSE3180 Semester 1 2005 week 2 / 39
Logical Data Modelling Logical Data Modelling
shiphands shipssail
Relationships Representation
CSE3180 Semester 1 2005 week 2 / 40
Logical Data ModellingLogical Data Modelling
Cardinality
Meaning : ONE Meaning : MANY
Course Units
CSE3180 Semester 1 2005 week 2 / 41
Logical Data ModellingLogical Data Modelling
Mandatory - Optional Relationship
Artists paint Pictures
Unary Relationship
(BinaryRelationship)
Ternary Relationship
customers cars
dealers
buy
CSE3180 Semester 1 2005 week 2 / 42
Logical Data ModellingLogical Data Modelling
ENTITIES
RELATIONSHIPS
ATTRIBUTES
membership class
degree
domains
values
cardinality
modality
recursive
binary
n-ary
1 : 11 : NM : N
mandatory
optional
CSE3180 Semester 1 2005 week 2 / 43
Entity RelationshipsEntity Relationships
part
vendorwarehouse
quantity
delivers
Quantity is the amount of a particular ‘part’ shipped from a particular‘vendor’ to a particular ‘warehouse’.
Each entity may be a ‘one’ or‘many’ participant
CSE3180 Semester 1 2005 week 2 / 44
Logical Data ModellingLogical Data Modelling
• Modelling symbols - McFadden, Hoffer, Prescott
Mandatory One
Mandatory Many - at least One
Optional One - No less than One
Optional Many - May be none
There is NO standard notation for E-R Modelling
CSE3180 Semester 1 2005 week 2 / 45
The Monash GalleryThe Monash Gallery
Exhibition Carrier
Contact
ArtistHistory
Gallery
ExhibitionCategory
Contract CollectionBuyer
Invoice
Payment
ItemArtist
ArtistCategory
Category
CSE3180 Semester 1 2005 week 2 / 46
Data Modelling ThoughtsData Modelling Thoughts
Nation Stock
nation code stock codenation name firm nameexchange rate stock price stock qty
stock divdnd
A 1:M relationship
Entities
Attributes
CSE3180 Semester 1 2005 week 2 / 47
Data Modelling ThoughtsData Modelling Thoughts
Nation State City
Name Statename Cityname Population Statepop Citypop Area State area City Area
Questions : Is the Nation ‘Population’ necessary ? Is the State ‘Population’ necessary ?
CSE3180 Semester 1 2005 week 2 / 48
Data Modelling ThoughtsData Modelling Thoughts
Library Book Borrower
libname callno borrower ID ISBN booktitle duedate
Library Book Copy Borrower
libname callno bookno borrowerID ISBN due date title
Physical Objects
CSE3180 Semester 1 2005 week 2 / 49
A Project Management Data ModelA Project Management Data Model
Project Management involves Planned and Actual data
A Project is normally divided into a number of Activities which require Resources
Planning requires an estimation of consumable resources
Employee Activity Project
empno planned hours project id
Daily Work
workdate
actual hours
CSE3180 Semester 1 2005 week 2 / 50
A Project Management Data ModelA Project Management Data Model
Planned Hours is an attribute of Activity
Actual Hours is an attribute of Daily Work
The time(hours) spent on an Activity would be the sum of actual hours in the Daily Work entity
This is probably workable, if planning is done at the Activity level and employees submit daily worksheets (or details are captured by electronic means)
Planning could be more detailed if Planners were able to indicate how many hours of each day each employee should spend on a project
CSE3180 Semester 1 2005 week 2 / 51
A Project Management Data ModelA Project Management Data Model
This model shows planned hours and actual hours asattributes of Daily Work
Employee
empno
Activity Project
project id
Daily Workworkdateplanned hoursactual hours
CSE3180 Semester 1 2005 week 2 / 52
Data Modelling ThoughtsData Modelling Thoughts
An interesting data model can be constructed which deals with aircraft leasing;
An aircraft broker will ‘own’ many aircraft which will be leased to a variety and number of airline companies (including of course Ansett and Qantas)
When a lease expires, the broker leases the plane to another airline company, which explains why there are some aircraft still flying which are 20 to 30 years old.
.
CSE3180 Semester 1 2005 week 2 / 53
Data Modelling ThoughtsData Modelling Thoughts
In this scenario, an aircraft can be leased many times, and an airline company can lease many aircraft.
Normally there is an agent handling each such deal. An agent can lease many aircraft and deal with many airlines. A transaction occurs when a deal is reached with an airline to lease an aircraft or a number of aircraft
CSE3180 Semester 1 2005 week 2 / 54
Modelling the Aircraft ScenarioModelling the Aircraft Scenario
Aircraft Aircraft- Agent Agent
aircraft code Agent ID
Airline- Airline Airline-Aircraft Agent
airlinename
An Aircraft - Airline - Agent data model
CSE3180 Semester 1 2005 week 2 / 55
Modelling the Aircraft ScenarioModelling the Aircraft Scenario
There is a bit of a problem here.
Where is the data relevant to the lease to be stored ( and how many times, and therefore how many versions ? - and which of these is the correct current value ?)
It could be in Airline-Aircraft.
If so, the agent responsible for the deal is ignored. Should it be in Agent-Airline ?
What is the problem here ?
CSE3180 Semester 1 2005 week 2 / 56
Modelling the Aircraft ScenarioModelling the Aircraft Scenario
A solution:
Aircraft Lease Agent
aircraftcode start date agentid
Airline
Airlinename
CSE3180 Semester 1 2005 week 2 / 57
A PuzzleA Puzzle
How can these dots be joined by 4 straight lines without lifting a pencil (or pen) from the surface ?
CSE3180 Semester 1 2005 week 2 / 58
A PuzzleA Puzzle
No, that’s 5 lines
1
2
3
4
5
CSE3180 Semester 1 2005 week 2 / 59
A PuzzleA Puzzle
That’s worse - it’s6 lines
1
2
3
45
6
CSE3180 Semester 1 2005 week 2 / 60
A PuzzleA Puzzle
How about this ?
1
CSE3180 Semester 1 2005 week 2 / 61
TimetableTimetable
• The lecture will be held in B2.15 from 10.00am to midday on Thursdays
• Tutorials will be held
in Laboratory K 1.07 midday to 2.00pm
There are 16 terminals in the room