44220: Database Design & Implementation Review & Assignment 2 Ian Perry Room: C49 Tel Ext.:

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Data, Information, …

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Data  Information What is Data? a series of observations, measurements, or facts. What is Information? data that have been transformed into a meaningful and useful form for people. Information = Data + Structure + Context the same data can give different information if a different structure and/or context is applied.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Data + Structure <= a Database A database is: an organised collection of data. A database management system (DBMS) is: software designed to assist in maintaining and utilising large collections of data. A relational database management system (RDBMS) is: a specific type of DBMS, which is an implementation of Codd’s Relational Database Theory.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 The ‘Data Modelling Stack’

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Conceptual Model - ER Diagram Staff, Student, Course (SSC)

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Logical Model – Schema & Domains Schema: SSC Domains: StudentIdentifiers: Number, from 1 to 9999 Titles: Text, >=2 & <= 4 Characters, First Char Caps, e.g. Mr, Ms, Mrs, Miss, Prof, Dr. PersonNames: Text, <= 12 Characters, First Char Caps. OPoints: Number, from 0 to 100. StaffIdentifiers: Number, from 1001 to SPoints: Number, from 1 to 6. StaffBirthDates: Date, dd/mm/yyyy, >= 21 years before today. PayRates: Money, from £15,000 to £20,000, in £1,000 increments. CourseIdentifiers: Number, from 101 to 110. CourseNames: Text, <= 15 Characters, First Char Caps. CourseDurations: Number, 3, 6, 9 or 12 (Months).

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Logical Model – Relations 1 Relation: Student EnrolNo: StudentIdentifiers Title: Titles FirstName: PersonNames SurName: PersonNames OLevelPoints: OPoints Tutor: StaffIdentifiers Primary Key: EnrolNo Foreign Key: Tutor references Staff.StaffID Relation: Staff StaffID: StaffIdentifiers Title: Titles FirstName: PersonNames FamilyName: PersonNames ScalePoint: SPoints DOB: StaffBirthDates Primary Key: StaffID Foreign Key: ScalePoint references Pay.ScalePoint

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Logical Model – Relations 2 Relation: Pay ScalePoint: SPoints RateOfPay: PayRates Primary Key: ScalePoint Relation: Team CourseCode: CourseIdentifiers StaffID: StaffNumbers Primary Key: CourseCode & StaffD Foreign Key: CourseCode references Course.CourseCode Foreign Key: StaffID references Staff.StaffID Relation: Course CourseCode: CourseIdentifiers Name: CourseNames Duration: CourseDurations Primary Key: CourseCode

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 What is a Physical Data Model? The Physical Implementation (hardware & software) of a Logical Data Model: it is useless to progress to this stage of database development if your Logical Data Model is NOT demonstrably ‘robust’. Physical Data Model must enable: data to be stored (& maintained) in structured manner. retrieval of specific groupings of data (information?). There may be several constraints: depending upon the software application chosen.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Logical => Physical i.e. translate a ‘logical’ Database Schema into a ‘physical’ Database: Schema => Database Relations => Tables Attributes => Field Names Domains => Data Type Field Size Input Mask Validation Rule Key Fields=>Relationships

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Physical Implementation

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Implementing ‘rules’ of Domains Access provides 4 main ways to control the data that can be entered into individual fields. Data Type Number, Text, Memo, Date/Time, Currency, etc. Field Size (or Format) depends upon the Data Type chosen. Validation Rule to control the range of allowable values that can be entered into a field. Input Mask to force the data that is entered to conform to a particular shape/pattern.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Assignment 2 (50% of Module Marks) Deadline? 28 th April Read the Case Study carefully: Your Database MUST be able to ‘answer’ the 10 questions at the end of the Learn-by-Post Case Study. Two parts: implement your logical data model as a physical data model, using Microsoft Access. test this implementation thoroughly, by building a number of Database Queries (i.e. 10), i.e.: prove that the information requirements can actually be delivered.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Answer the Questions I have set! 1.Implement a Physical Data Model, i.e. a Microsoft Access Database; which supports requirements of the Case Study organisation. (50 Marks) This Physical Data Model MUST BE developed using Microsoft Access. Marks here will be awarded with respect to the following: Tables – are there sensible Table Names, Field Names & choice of Key Fields. Domains – how well have you attempted to control data entry by use of Field Type, Size, Format, Input Mask, Validation Rule, etc. Relationship Diagram – does it show all of the relationships, with referential integrity enforced, between the all of the above Tables? If you can’t enforce referential integrity for every relationship, then there is a problem with your database design.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Answer the Questions I have set! 2.Test this Physical Data Model; by developing a number of Queries that show that your database can deliver the information requirements, i.e. can answer the 10 questions from the Case Study. (50 Marks) These Database Queries MUST BE developed using Microsoft Access. You MUST develop 10, clearly named, queries (each worth 5 Marks) that provide ‘reasonable’ answers to the Questions of the Case Study organisation; e.g.: a)Who are our students? Remember to ADD ‘enough’ test data to your database tables in order to demonstrate that your Database can provide a ‘reasonable’ answer to each of the 10 questions.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 The 10 Questions (5 Marks each) a)Who are our students? b)Which students should attend examination centre X? c)What is the assessment/examination weighting for all of the available modules? d)Which tutor(s) is/are on the team for module X? e)Which tutors are module co-ordinators, and for which modules? f)Which module(s) has student X already taken? g)What module(s) is/are student X currently studying? h)Which modules are not yet fully marked, and who is the module co-ordinator? i)Which students should be sent a certificate for module X? j)Which module is the most difficult to pass? NB. Where the examination centre, module, or student is an X, then the user of the Database MUST be able to choose from at least 2 different values. Therefore, the queries that ‘answer’ these questions MUST BE parameter-based queries.

Ian PerrySlide : Database Design & Implementation: Review & Assignment 2 Workshops this Week & Next Assignment 2 Support If you want any help with Assignment 2, then make sure that you come to these sessions prepared to ask sensible questions. “Where do I begin?” - is NOT a sensible question! No Lecture Next Week You may be ‘glad’ to hear? Assignment 2 Deadline: 28th April 2006.