1. 1 Specification of IT Systems Mandatory Exercise Week 3 Jonas B. Jørgensen, 20021728 Rune Simonsen, 20022374 Torsten Aaboe Andersen, 20033031 Jesper G. Jensen, 20030396

2. 2 Exercise 1 - ERD

3. 3 Exercise 2 - Dictionary (1) Card reader. Entity type. A piece of hardware able to read access cards and accept pincodes(numbers). Keypad terminal. Entity type. A piece of hardware able to accept numbers (user ID and pincode) Card. Entity type. A piece of plastic of size approx. 5cm*6cm*2mm that contains an ID written on the card and in a magnetic area. Access control form. Entity type. A piece of paper the user fills out to gain access. Must contain studentID/employeeID, name, signature, expiry date and where the person wants access. Access log. Entity type. A log of when and to whom access is given. Access right. Entity type. A list of locations and corresponding timeframes in which a user has access. This list has an expire date.

4. 4 Exercise 2 - Dictionary (2) Logs access to (ah: Access hardware al: Access log). Relationship name. An access hardware terminal ah writes time and user for all given access in al. Can read (cr: Card reader c: Card). Relationship name. Cr can read the identification of the card. Exp. date. Attribute name. Describes the date where a users access rights expires.

5. 5 Consistency  Consistency

6. 6 Checking validity by elementary sentences  The user will always have exactly one card  Each location can have multiple access hardware  A user can access any location in his access right list  The card printer can write its actions in the card log. ...

7. 7 Checking Validity by snapshots  A student is issued a new card but his access rights contains no locations. (ok)  A location exists in the system but no users have access to the location. (ok)  An access right is created with an expire date earlier than the current date. (bad) ...