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Modelling LanguagesCONCEPTUAL DATA MODELLING

(c) 2017 Monique Snoeck

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Modelling language

• A Modelling language is a collection of modellingtechniques

• the Unified Modelling Language (UML) is a collection of over 9 different modelling techniques

1. Class diagrams

2. ...

3. ...

(c) 2017 Monique Snoeck

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Modelling techniqueModels are written in a “modelling technique”

= collection of symbols + composition rules

• Example• BPMN Process diagrams

(c) 2017 Monique Snoeck

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Modelling techniques• Modeling techniques range from

Purely textual to Purely formal

register anew member

front office

desk Use Case 1:

Register Member

Description:

Regsitration of a new member

Precondition:

Member does not exist yet.

Steps:

Input the member's details into

the system

Checks uniqueness of member

Register member in the system

LOAN_ITEM = <{borrow, return, lose}, create_item.classify.(borrow.return)*.(borrow.lose + 1).declassify. remove_item>

BOOK =<{renew},create_item.classify.(borrow.(renew)*.return)*.(borrow.(renew)*.lose +1).declassify.remove_item>

(BOOK)|a LOAN_ITEM ║ LOAN_ITEM = LOAN_ITEM BOOK LOAN_ITEM

VOLUME = <{}, create_item.classify.(borrow.return)*.(borrow.lose + 1).declassify.remove_item

UMLCD

(c) 2017 Monique Snoeck

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Modelling techniques• There is a plentitude of modelling techniques for IS

• Entity Relationship Modelling

• UML Class diagram

• UML State chart

• Flow Charts

• Process Diagrams

• Petri Nets

• Event Process Chains (EPC)

• ...

(c) 2017 Monique Snoeck

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Modelling techniques

• Different models are used for different phases and different viewpoints

• PhaseAbstract/Conceptual Detailed

Implementation Agnostic Implementation Oriented

• ViewpointsData perspective Behavioural perspective Interaction perspective

(c) 2017 Monique Snoeck

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Modelling techniques

• Some techniques address the same viewpoint & phase, but use different symbols

• Business process modelling• BPMN Process diagrams

• Petri Nets

• Conceptual data modelling

• ER modelling

• UML Class diagram

Task 1 Task 2

Person Subscription(1,1) (0,N)Name Date

Person

String Name

Subscription

TimeStamp: Date1 0..*

(c) 2017 Monique Snoeck

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Modelling techniques

Sometimes the same technique is used through different phases

UML class diagram used for conceptual modelling

versus

UML class diagram used for program design

(c) 2017 Monique Snoeck

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Data modelling techniques

Extended Entity Relationship modelling• Invented by Peter Chen for the conceptual design of

databases.

• Later extended with insights from semantic modelling Extended Entity Relation (EER) modelling

Person Subscription(1,1) (0,N)Name Date

(c) 2017 Monique Snoeck

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Data modelling techniques

• Information Engineering (Crow's foot notation)

Person Subscription

(c) 2017 Monique Snoeck

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Data modelling techniques• UML Class Diagram

• Part of Unified Modelling Language

• Originates from Object Oriented Programming

• Represents data aspect of classes

Person

String Name

Subscription

TimeStamp: Date1 0..*

(c) 2017 Monique Snoeck

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Entity Class Entity

Data modelling techniques

EER UML InformationEngineering

0..1 0..*(0..1) (0..n)

1..1 1..*(1..1) (1..n)

(c) 2017 Monique Snoeck