1. Specification of IT Systems Mandatory Exercise Week 3 Group 3, Søren Vestergaard, Smari Waage, Belma Boyraz, Jannick Hoy

2. 2 Entity Relationship Diagram

3. 3 Dictionary #1 Travel element. Entity type. A description of a basic element of travel. It contains information on deadlines, description, type and location, depending on type. Types are: plane trip, car rental, hotel booking or a daytrip, but more types can be added. Travel elements are a part of a package, but can stand on their own. Itinerary. Entity type. An instance of the itinerary. An itinerary is a collection of the user’s selected packages and travel elements. Package. Entity type. A collection of travel elements, either made by the administrator or the user. User. Entity type. User of the system.

4. 4 Dictionary #2 Reservation(p: package u : user). Relationship name. A user u has reserved a package p. Location. Attribute name. Describes a travel-destination or source. Advertisement. Entity type. A suggestion of travel elements and/or packages that may be relevant to the user.

5. Validation - Consistency Package User 1 * Travel Element Advertisement reserved suggested by * 1..* consists of * * 1..* *

6. 6 Validation – Elementary Sentences “A user can reserve any number of packages” “A package is reserved by one user” “A package consists of at least one travel element” “A travel element can be contained in any number of packages” “Each advertisement suggests at least one travel element and each travel element can be suggested by any number of advertisements” “User gets presented any number of advertisements, and an advertisement is presented to any number of users”

7. Validation – Snapshots RESERVATIONUser NamePackage A1-Flight & HotelKate BigsbyeT.E: Flight (Aarhus - Istanbul) T.E: Hotel (The Marmara) Return Date: 15-10-2006 10:25 13:00 Departure Date: 30-09-2006 09:10 -11:15 RESERVATIOUser namePackage A1- Rent a carKate BigsbyeT.E: Rent a car Place: Istanbul Ataturk Airport Date:30-09-2006 Time: 11:20

8. Validation - Identification In our subject domain, we can communicate with external databases but we can’t say anything about them.