44220: Database Design & Implementation Review & Assignment 2 Ian Perry Room: C41C Tel Ext.: 7287 E-mail: [email protected]@hull.ac.uk

44220: Database Design & Implementation

Review & Assignment 2

Ian PerryRoom: C41C Tel Ext.: 7287

E-mail: [email protected]

http://itsy.co.uk/ac/0708/sem2/44220_DDI/

Ian Perry Slide 244220: Database Design & Implementation: Review & Assignment 2

Data, Information, …


The ‘Data Modelling Stack’

Conceptual Overview of things that are perceived to be of ‘interest’ in the ‘real’ world.

Model of the Business System. (ER Model)

Logical Data elements & the relationships between those elements in a tabular form.

Model of Data Storage Theory (Db Schema)

Physical Actual data held in a database & the means to manipulate that data.

Physical Implementation (RDBMS)


Conceptual Model - ER Diagram

Staff, Student, Course (SSC)

Staff Student

Team Course

Pay tutor for =>

<= tutored by

1 M

1

11

M

M

M<= taught by

applies to =>

<= paid at<

= p

art o

f

IndicatesMandatory

Participation

Staff Student

Team Course

Pay tutor for =>

<= tutored by

1 M

1

11

M

M

M<= taught by

applies to =>

<= paid at<

= p

art o

f

IndicatesMandatory

Participation


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 1199. 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).


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


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


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.


Logical => Physical i.e. translate a ‘logical’ Database

Schema into a ‘physical’ Database: Schema => Database Relations => Tables Attributes => Field Names Domains => Data Type

Field SizeInput MaskValidation Rule

Key Fields => Relationships


Physical Implementation - 1


Physical Implementation - 2

The ‘Team’ Table has composite Primary Key, consisting of BOTH;

CourseCode & StaffID You MUST set up relationships between ALL of the Tables of your

Database, with referential integrity enforced, BEFORE you; ADD any DATA to your Tables, BUILD any QUERIES to answer Questions.


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.


Assignment 2 (50% of Module Marks)

Deadline? Friday, the 9th of May.

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; Using Data Type, Field Size, Input Masks & Validation

Rules as appropriate in order to constrain domains. test this implementation thoroughly, by

building 10 Database Queries; i.e. prove that the information requirements can

actually be delivered.


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 Data Type, Field Size, 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?

NB. If you can’t enforce referential integrity for every relationship, then there is a problem with your database design/implementation.


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?B. Which tutors are module co-ordinators, and for which

modules?C. Which students should be sent a certificate for module X?

AND 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.


The 10 Questions (5 Marks each)

Your database MUST be able to ‘answer’ the following questions:

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 & 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.


Get on with it! No More Lectures

You may be ‘glad’ to hear? TWO Assignment 2 Support Workshops

i.e. this week & next. If you want any help with Assignment 2,

then make sure that you come to these support sessions prepared to ask sensible questions. “Where do I begin?” - is NOT a sensible

question! Assignment 2 Deadline:

Friday, the 9th of May.

Documents

44220: Database Design & Implementation Review & Assignment 2 Ian Perry Room: C41C Tel Ext.: 7287 E-mail: [email protected]@hull.ac.uk