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

44220: Database Design & Implementation

Implementing Physical Domains

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: Implementing Physical Domains

The SSC Database

Relations Staff (StaffID, FirstName, SurName, ScalePoint, DOB) Student (EnrolNo, FirstName, SurName, OLevelPoints,

Tutor) Course (CourseCode, Name, Duration) Team (CourseCode, StaffID) Pay (ScalePoint, RateOfPay)

ER Diagram

Staff Course Student1 MN M


Domains Schema SSC Domains

StaffIdentifiers = 1001 - 1199; StudentIdentifiers = 2000 - 9999; Titles = Mr, Ms, Mrs, Dr; PersonNames = String, <= 12 Characters; CourseIdentifiers = 101 - 110; CourseNames = Computing, Law, …,

Marketing; CourseDurations = 3, 6, 9, 12; OLevelPoints = 0 - 240; ScalePoints = 1 - 6; PayRates = £13,000, £13,500, …, £15,500; BirthDates = Date, >= 21 Years before

Today;


Relations – Staff & Student Relation Staff

StaffID: StaffIdentifiers; Title: Titles; FirstName: PersonNames; SurName: PersonNames; ScalePoint: ScalePoints; DOB: BirthDates;

Primary Key: StaffID Foreign Key: ScalePoint refs

Pay.ScalePoint

Relation Student EnrolNo: StudentIdentifiers; Title: Titles; FirstName: PersonNames; SurName: PersonNames; OLevelPoints: OLevelPoints; Tutor: StaffIdentifiers;

Primary Key: EnrolNo Foreign Key: Tutor refs Staff.StaffID


Relations – Course, Team & Pay

Relation Course CourseCode: CourseIdentifiers; Name: CourseNames; Duration: CourseDurations;

Primary Key: CourseCode

Relation Team CourseCode: CourseIdentifiers; StaffID: StaffIdentifiers;

Primary Key: CourseCode & Staff-ID Foreign Key: CourseCode refs

Course.CourseCode Foreign Key: StaffID refs Staff.StaffID

Relation Pay ScalePoint: ScalePoints; RateOfPay: PayRates;

Primary Key: ScalePoint


Logical => Physical Translating a Logical Model (e.g. a

Database Schema) into a Physical Model (e.g. an Access Database) requires the following: Schema => Database Relations => Tables Attributes => Field Names Domains => Data Type

Field SizeValidation RuleInput Mask

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.


Controlling Data Entry 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.


Data Type & Field Size Number

Default = Long Integer; However, ALWAYS store numbers using the smallest

possible Field Size. Byte;

whole numbers, positive only, between 0 and 255. Integer;

whole numbers between –32,768 and 32,767. Long Integer (Default);

whole numbers between –2,147,483,648 and 2,147,483,647.

Single; large numbers, both positive & negative, including

decimal places. Double;

very large numbers, both positive & negative, including decimal places.


Data Type & Field Size Text

from 1 to 255 characters (Default = 255).

Domain PersonNames = String, <= 12 Characters;

Attribute FirstName: PersonNames;

Field Definition Field Name :- FirstName Data Type :- Text Field Size :- 12

Memo Field Size cannot be altered, but can

accommodate up to 63,999 characters.


Data Type & Format Date/Time

can accommodate Date and Time values between the Years 100 and 9999.

NB. Format ‘decides’ how a Date is displayed. Domain

BirthDates = Date, >= 21 Years before Today;

Attribute DOB: BirthDates;

Field Definition Field Name :- DOB Data Type :- Date/Time Format :- Long Date


Data Type & Format Currency

As with Date/Time fields, Format ‘decides’ how Currency fields are displayed.

Domain PayRates = £13,000, £13,500, …, £15,500;

Attribute RateOfPay: PayRates;

Field Definition Field Name :- RateOfPay Data Type :- Currency Format :- Currency


Validation Rules To control the range of allowable values

that can be entered into a field. e.g. Numeric Ranges

Domain StaffIdentifiers = 1001 - 1199;

Attribute StaffID: StaffIdentifiers;

Field Definition Field Name :- StaffID Data Type :- Number Field Size :- Integer Validation Rule :- >=1001 And <=1199 Validation Text :- Must be > 1000 And < 1200


Validation Rules e.g. Specific Numbers

Domain CourseDurations = 3, 6, 9, 12;

Attribute Duration: CourseDurations;

Field Definition Field Name :- Duration Data Type :- Number Field Size :- Byte Validation Rule :- 3 Or 6 Or 9 Or 12 Validation Text :- 3, 6, 9 or 12 months

only.


Validation Rules e.g. Patterns of Text

Domain Titles = Mr, Ms, Mrs, Dr;

Attribute Title: Titles;

Field Definition Field Name :- Title Data Type :- Text Field Size :- 3 Validation Rule :- “Mr” Or “Ms” Or “Mrs” Or

“Dr” Validation Text :- Mr, Ms, Mrs or Dr only.


Input Masks To force the data that is entered to

conform to a particular shape/pattern. Domain

PersonNames = String, <= 12 Characters;

Attribute SurName: PersonNames;

Field Definition Field Name :- SurName Data Type :- Text Field Size :- 12 Input Mask :- >L<L??????????


A little bit of Everything! Always attempt to constrain the domain

of each Field in as many ways as possible: Domain

Titles = Mr, Ms, Mrs, Dr; Attribute

Title: Titles; Field Definition

Field Name :- Title Data Type :- Text Field Size :- 3 Input Mask :- >L<L? Validation Rule :- “Mr” Or “Ms” Or “Mrs” Or “Dr” Validation Text :- Mr, Ms, Mrs or Dr only.


This Week’s Workshop Implementing Physical Domains

in Microsoft Access: Data Types Field Sizes Input Masks Validation Rules

Remember: I will be looking carefully for evidence of

you attempting to use all of the above, when judging the quality of the Implementation of your Database for Assignment 2.


The Next 4 Weeks There will be NO Lecture or Workshop

sessions next week! I have to attend a meeting at the Hull Campus.

The Final Lecture will take place; Thursday, the 24th of April.

There will be two more Assignment 2 Support workshops, i.e.; Thursday, the 24th of April. Thursday, the 1st of May.

The Assignment 2 Deadline is; Thursday, the 8th of May.

Documents

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