9/7/1999Information Organization and Retrieval Database Design: Conceptual Model and ER Diagramming University of California, Berkeley School of Information.

9/7/1999 Information Organization and Retrieval

Database Design: Conceptual Model and ER Diagramming

University of California, Berkeley

School of Information Management and Systems

SIMS 202: Information Organization and Retrieval


Review

• Database Design Process

• Basics of ER Diagrams


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


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


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


Relationships

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


Relationships

ClassAttendsStudent

PartSuppliesproject

partsSupplier

Project


Types of Relationships

• Concerned only with cardinality of relationship

TruckAssignedEmployee

ProjectAssignedEmployee

ProjectAssignedEmployee

1 1

n

n

1

m


More Complex Relationships

ProjectEvaluationEmployee

Manager

1/n/n

1/1/1

n/n/1

ManagesEmployee

ProjectAssignedEmployee 4(2-10) 1

SSN ProjectDate

Manages

Is Managed By

1

n


Weak Entities

• Owe existence entirely to another entity

Order-lineContainsOrder

Invoice #

Part#

Rep#

QuantityInvoice#


Supertype and Subtype Entities

ClerkIs one ofSales-rep

Invoice

Other

Employee

Sold

Manages


Many to Many Relationships

Employee

ProjectIsAssigned

ProjectAssignment

Assigned

SSN

Proj#

SSN

Proj#Hours


Today

• Building the Conceptual Model for the Diveshop database

• Names for the Diveshop company?


Developing a Conceptual Model

• We will look at a small business -- a diveshop that offers diving adventure vacations

• Assume that we have done interviews with the business and found out the following information about the forms used and types of information kept in files and used for business operations...


Primary Business Operations• The shop takes orders from customers for dive

vacations.

• It ships information about the dive vacation to the customers.

• It rents diving equipment for the divers going on the trips (these may include additional people other than the customer)

• It bills the customer for the vacation and for equipment rental or sales.


Business Operations (cont.)

• It arranges sub-trips to particular dive sites at the primary location.

• It provides information about the features of various sites to help customers choose their destinations.– Features include sea life found at the location

and shipwrecks


Business Operations (cont.)• Each dive order (or sale or trip) is on an invoice

to one customer.– Invoices contain:

• Line items for each type of equipment ordered,• Total amount due for the invoice,• Customer information:

– Name, address, phone, credit card info.

• Information must be kept on inventory of dive equipment.

• There are multiple types of dive equipment:– The prices charged for sale or rental are maintained.


Business Operations (cont.)• Destination information includes:

– Name of the destination– information about the location (accomodations,

night life, travel cost, average temperatures for different times of the year

• Destinations have associated dive sites.• Dive Sites have associated features

– Sea life – Shipwrecks


Business Operations (cont.)

• One record is kept for each order by a customer and will include the method of payment, total price, and location information. (I.e. Customers may have multiple orders)

• The company needs to know how an order is to be shipped.

• The shop has to keep track of what equipment is on-hand and when replacements or additional equipment is needed


Entities

• Customer• Dive Order• Line item• Shipping information• Dive Equipment/

Stock/Inventory• Dive Locations

• Dive Sites• Sea Life• Shipwrecks


Diveshop ER Entities: DiveCust

Name

Customer no

Street

State/ProvCityZIP/Postal

Code

Country

First Contact

PhoneDiveCust


Diveshop ER Entities: DiveOrds

CustomerNo

Order no

SaleDate

ShipVia

TotalInvoice

DestinationCCExpDate

CCNumber

PaymentMethodDiveOrds

No ofPeople

VacationCost

ReturnDate

DepartDate


Diveshop ER Entities: DiveItem

Item no

Order no

Rental/Sale

Qty

Line Note

DiveItem


Diveshop ER Entities: ShipViaShip Via

ShipCost

ShipVia


Diveshop ER Entities: DiveStok

Description

Item No

EquipmentClass

ReorderPoint

On Hand Cost

SalePrice

DiveStokRentalPrice


Diveshop ER Entities: Dest

Destinationname

Destination no

Avg Temp (F)

SpringTemp (F)

Avg Temp (C)

Summer Temp (C)

SummerTemp (F)

TravelCost

WinterTemp (C)

FallTemp (F)

FallTemp (C)Dest

WinterTemp (F)

Accommodations

Body ofWater

NightLife


Diveshop ER Entities: Sites

Destinationno

Site no

Site Name

SiteNotes

SiteHighlight

DistanceFrom Town (M)

DistanceFrom Town (Km)

Skill Level

Visibility(ft)

Depth (m)

Depth (ft)Sites

Visibility (m)


Diveshop ER Entities: Biolife

Category

Species no

CommonName

Length(cm)

SpeciesName

Length(in)

Notes

GraphicBioLife


Diveshop ER Entities: Shipwrck

Site no

Ship Name

Category

InterestType Tonnage

Length (ft)

Beam(m)

Beam(ft)

Length(m)Shipwrck

Cause

CommentsDateSunk

Passengers/Crew

Graphic

Survivors

Condition


Functional areas

• Ordering• Inventory• Supplies• Shipping• Billing• Location/Site Selection

– We will concentrate on Ordering and Location/Site Selection (these are joined tasks)


Ordering

Orders(DIVORDS)

Customer(DIVECUST)

Customers place OrdersEach Order needs Customer information


Ordering

DiveOrdsOrdersDiveCust

Customer No ship

ShipVia

Order No

Ship Via

DiveItem Repeatingattribute

Customer No


Ordering Normalization

DiveCust Orders

Customer No

DiveOrds

Ship

ShipVia

Order No

Ship Via

DiveItemContains

Item No

QtyOrder No

Customer NoRental/sale


Details of DiveItem

DiveStokSuppliesSupplier

Company# Has

DiveItem

Item No

Item No

On Hand

Sale Price

Order No

m n

We’re ignoring this part...


Ordering: Full ERCustomer

No

ShipVia

DestShipVia

DiveStok

DiveItem

DiveOrds

DiveCust

CustomerNo

ShipVia

OrderNo

OrderNo

ItemNo

ItemNo

DestinationName

Destination

Destinationno 1

1

1

1

1n

n

n

n

n


Location/Site Selection

DestGoing

to?DiveOrds

DestinationNo

DestinationName

Destination


Destination/ Sites

Dest

Sites

DiveOrds

CustomerNo

OrderNo

DestinationName

DestinationSite No

Destinationno

Destinationno

1

1

n

n


Sites and Sea Life 1

BioLife

Sites

Site NoDestination

no

Multiple occurrencesof sea life...


Diveshop ER diagram: BioSiteSpecies

NoSiteNo

BioSite


Sites and Sea Life 2

Sites

BioSite

BioLifeSpeciesNo

Site No

Site No

Destinationno

SpeciesNo

1

1

n

n


Sites and Shipwrecks

Sites

ShipWrck

Site NoDestination

no

Site No

1/n

1


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


What must be calculated?

• Total price for equipment rental?

• Total price for equipment sale?

• Total price of an order?– Vacation price– Equipment (rental or sale)– Shipping


What is Missing??

• Not really an “enterprise-wide” database– No personnel

• Sales people• Dive masters• Boat captains and crew• payroll

– Local arrangements• Dive Boats• Hotels

– Suppliers/Wholesalers for dive equipment• Orders for new/replacement equipment

9/7/1999Information Organization and Retrieval Database Design: Conceptual Model and ER Diagramming University of California, Berkeley School of Information.

Documents

information organization

retrieval slide

types of information

information persons

following information

retrieval entity

n slide

companies employee slide