9/7/1999Information Organization and Retrieval Database Design: Conceptual Model and ER Diagramming University of California, Berkeley School of Information.
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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
9/7/1999 Information Organization and Retrieval
Review
• Database Design Process
• Basics of ER Diagrams
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
Relationships
• Relationships are the associations between entities. They can involve one or more entities and belong to particular relationship types
9/7/1999 Information Organization and Retrieval
Relationships
ClassAttendsStudent
PartSuppliesproject
partsSupplier
Project
9/7/1999 Information Organization and Retrieval
Types of Relationships
• Concerned only with cardinality of relationship
TruckAssignedEmployee
ProjectAssignedEmployee
ProjectAssignedEmployee
1 1
n
n
1
m
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
Weak Entities
• Owe existence entirely to another entity
Order-lineContainsOrder
Invoice #
Part#
Rep#
QuantityInvoice#
9/7/1999 Information Organization and Retrieval
Supertype and Subtype Entities
ClerkIs one ofSales-rep
Invoice
Other
Employee
Sold
Manages
9/7/1999 Information Organization and Retrieval
Many to Many Relationships
Employee
ProjectIsAssigned
ProjectAssignment
Assigned
SSN
Proj#
SSN
Proj#Hours
9/7/1999 Information Organization and Retrieval
Today
• Building the Conceptual Model for the Diveshop database
• Names for the Diveshop company?
9/7/1999 Information Organization and Retrieval
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...
9/7/1999 Information Organization and Retrieval
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.
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
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.
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
Entities
• Customer• Dive Order• Line item• Shipping information• Dive Equipment/
Stock/Inventory• Dive Locations
• Dive Sites• Sea Life• Shipwrecks
9/7/1999 Information Organization and Retrieval
Diveshop ER Entities: DiveCust
Name
Customer no
Street
State/ProvCityZIP/Postal
Code
Country
First Contact
PhoneDiveCust
9/7/1999 Information Organization and Retrieval
Diveshop ER Entities: DiveOrds
CustomerNo
Order no
SaleDate
ShipVia
TotalInvoice
DestinationCCExpDate
CCNumber
PaymentMethodDiveOrds
No ofPeople
VacationCost
ReturnDate
DepartDate
9/7/1999 Information Organization and Retrieval
Diveshop ER Entities: DiveItem
Item no
Order no
Rental/Sale
Qty
Line Note
DiveItem
9/7/1999 Information Organization and Retrieval
Diveshop ER Entities: ShipViaShip Via
ShipCost
ShipVia
9/7/1999 Information Organization and Retrieval
Diveshop ER Entities: DiveStok
Description
Item No
EquipmentClass
ReorderPoint
On Hand Cost
SalePrice
DiveStokRentalPrice
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
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)
9/7/1999 Information Organization and Retrieval
Diveshop ER Entities: Biolife
Category
Species no
CommonName
Length(cm)
SpeciesName
Length(in)
Notes
GraphicBioLife
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
Functional areas
• Ordering• Inventory• Supplies• Shipping• Billing• Location/Site Selection
– We will concentrate on Ordering and Location/Site Selection (these are joined tasks)
9/7/1999 Information Organization and Retrieval
Ordering
Orders(DIVORDS)
Customer(DIVECUST)
Customers place OrdersEach Order needs Customer information
9/7/1999 Information Organization and Retrieval
Ordering
DiveOrdsOrdersDiveCust
Customer No ship
ShipVia
Order No
Ship Via
DiveItem Repeatingattribute
Customer No
9/7/1999 Information Organization and Retrieval
Ordering Normalization
DiveCust Orders
Customer No
DiveOrds
Ship
ShipVia
Order No
Ship Via
DiveItemContains
Item No
QtyOrder No
Customer NoRental/sale
9/7/1999 Information Organization and Retrieval
Details of DiveItem
DiveStokSuppliesSupplier
Company# Has
DiveItem
Item No
Item No
On Hand
Sale Price
Order No
m n
We’re ignoring this part...
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
Location/Site Selection
DestGoing
to?DiveOrds
DestinationNo
DestinationName
Destination
9/7/1999 Information Organization and Retrieval
Destination/ Sites
Dest
Sites
DiveOrds
CustomerNo
OrderNo
DestinationName
DestinationSite No
Destinationno
Destinationno
1
1
n
n
9/7/1999 Information Organization and Retrieval
Sites and Sea Life 1
BioLife
Sites
Site NoDestination
no
Multiple occurrencesof sea life...
9/7/1999 Information Organization and Retrieval
Diveshop ER diagram: BioSiteSpecies
NoSiteNo
BioSite
9/7/1999 Information Organization and Retrieval
Sites and Sea Life 2
Sites
BioSite
BioLifeSpeciesNo
Site No
Site No
Destinationno
SpeciesNo
1
1
n
n
9/7/1999 Information Organization and Retrieval
Sites and Shipwrecks
Sites
ShipWrck
Site NoDestination
no
Site No
1/n
1
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
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
9/7/1999 Information Organization and Retrieval
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
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