9/7/1999Information 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

9/7/1999Information Organization and Retrieval Review Database Design Process Basics of ER Diagrams

9/7/1999Information Organization and Retrieval Database Design Process Conceptual Model Logical Model External Model Conceptual requirements Conceptual requirements Conceptual requirements Conceptual requirements Application 1 Application 2Application 3Application 4 Application 2 Application 3 Application 4 External Model External Model External Model Internal Model

9/7/1999Information 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

9/7/1999Information 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

9/7/1999Information Organization and Retrieval Relationships Relationships are the associations between entities. They can involve one or more entities and belong to particular relationship types

9/7/1999Information Organization and Retrieval Relationships Class Attends Student Part Supplies project parts Supplier Project

9/7/1999Information Organization and Retrieval Types of Relationships Concerned only with cardinality of relationship Truck Assigned Employee Project Assigned Employee Project Assigned Employee 11 n n 1 m

9/7/1999Information Organization and Retrieval More Complex Relationships Project Evaluation Employee Manager 1/n/n 1/1/1 n/n/1 Manages Employee Project Assigned Employee 4(2-10)1 SSNProjectDate Manages Is Managed By 1 n

9/7/1999Information Organization and Retrieval Weak Entities Owe existence entirely to another entity Order-line Contains Order Invoice # Part# Rep# QuantityInvoice#

9/7/1999Information Organization and Retrieval Supertype and Subtype Entities Clerk Is one of Sales-rep Invoice Other Employee Sold Manages

9/7/1999Information Organization and Retrieval Many to Many Relationships Employee Project Is Assigned Project Assignment Assigned SSN Proj# SSN Proj# Hours

9/7/1999Information Organization and Retrieval Today Building the Conceptual Model for the Diveshop database Names for the Diveshop company?

9/7/1999Information 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...

9/7/1999Information 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.

9/7/1999Information 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

9/7/1999Information 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.

9/7/1999Information 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

9/7/1999Information 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

9/7/1999Information Organization and Retrieval Entities Customer Dive Order Line item Shipping information Dive Equipment/ Stock/Inventory Dive Locations Dive Sites Sea Life Shipwrecks

9/7/1999Information Organization and Retrieval Diveshop ER Entities: DiveCust Name Customer no Street State/ProvCity ZIP/Postal Code Country First Contact Phone DiveCust

9/7/1999Information Organization and Retrieval Diveshop ER Entities: DiveOrds Customer No Order no Sale Date Ship Via Total Invoice Destination CCExpDate CCNumber Payment Method DiveOrds No of People Vacation Cost Return Date Depart Date

9/7/1999Information Organization and Retrieval Diveshop ER Entities: DiveItem Item no Order no Rental/ Sale Qty Line Note DiveItem

9/7/1999Information Organization and Retrieval Diveshop ER Entities: ShipVia Ship Via Ship Cost ShipVia

9/7/1999Information Organization and Retrieval Diveshop ER Entities: DiveStok Description Item No Equipment Class Reorder Point On HandCost Sale Price DiveStok Rental Price

9/7/1999Information Organization and Retrieval Diveshop ER Entities: Dest Destination name Destination no Avg Temp (F) Spring Temp (F) Avg Temp (C) Summer Temp (C) Summer Temp (F) Travel Cost Winter Temp (C) Fall Temp (F) Fall Temp (C) Dest Winter Temp (F) Accommodations Body of Water Night Life

9/7/1999Information Organization and Retrieval Diveshop ER Entities: Sites Destination no Site no Site Name Site Notes Site Highlight Distance From Town (M) Distance From Town (Km) Skill Level Visibility(ft) Depth (m) Depth (ft) Sites Visibility (m)

9/7/1999Information Organization and Retrieval Diveshop ER Entities: Biolife Category Species no Common Name Length (cm) Species Name Length (in) Notes Graphic BioLife

9/7/1999Information Organization and Retrieval Diveshop ER Entities: Shipwrck Site no Ship Name Category InterestTypeTonnage Length (ft) Beam (m) Beam (ft) Length (m) Shipwrck Cause Comments Date Sunk Passengers/ Crew Graphic Survivors Condition

9/7/1999Information 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)

9/7/1999Information Organization and Retrieval Ordering Orders (DIVORDS) Customer (DIVECUST) Customers place Orders Each Order needs Customer information

9/7/1999Information Organization and Retrieval Ordering DiveOrds Orders DiveCust Customer No ship ShipVia Order No Ship Via DiveItem Repeating attribute Customer No

9/7/1999Information Organization and Retrieval Ordering Normalization DiveCust Orders Customer No DiveOrds Ship ShipVia Order No Ship Via DiveItem Contains Item No QtyOrder No Customer No Rental/sale

9/7/1999Information Organization and Retrieval Details of DiveItem DiveStok Supplies Supplier Company# Has DiveItem Item No On Hand Sale Price Order No mn We’re ignoring this part...

9/7/1999Information Organization and Retrieval Ordering: Full ER Customer No ShipVia Dest ShipVia DiveStok DiveItem DiveOrds DiveCust Customer No ShipVia Order No Order No Item No Item No Destination Name Destination no n n n n n

9/7/1999Information Organization and Retrieval Location/Site Selection Dest Going to? DiveOrds Destination No Destination Name Destination

9/7/1999Information Organization and Retrieval Destination/ Sites Dest Sites DiveOrds Customer No Order No Destination Name Destination Site No Destination no Destination no 1 1 n n

9/7/1999Information Organization and Retrieval Sites and Sea Life 1 BioLife Sites Site No Destination no Multiple occurrences of sea life...

9/7/1999Information Organization and Retrieval Diveshop ER diagram: BioSite Species No Site No BioSite

9/7/1999Information Organization and Retrieval Sites and Sea Life 2 Sites BioSite BioLife Species No Site No Destination no Species No 1 1 n n

9/7/1999Information Organization and Retrieval Sites and Shipwrecks Sites ShipWrck Site No Destination no Site No 1/n 1

9/7/1999Information Organization and Retrieval DiveShop ER Diagram Customer No ShipVia Dest Sites BioSite ShipVia ShipWrck BioLife DiveStok DiveItem DiveOrds DiveCust Customer No ShipVia Order No Order No Item No Item No Destination Name Destination Species No Site No Destination no Site No Destination no Species No Site No /n 1 1 n n n n n n n n 1

9/7/1999Information 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

9/7/1999Information 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