Samenvatting slides boek Ontwerp van informatiesystemen

Ontwerp van Informatesystemen

Table of Contents

Hoofdstuk 1: Wat is systeemontwerp?...............................................................................3
Inleiding.......................................................................................................................................3
Informatesystemen......................................................................................................................3
Organisates en IS..........................................................................................................................3
Software engineering....................................................................................................................4
Watervalmodel.............................................................................................................................5
Analyse..........................................................................................................................................5
Ontwerp........................................................................................................................................5
Implementate...............................................................................................................................5
Testen...........................................................................................................................................6
Onderhoud....................................................................................................................................6
Nuancering....................................................................................................................................6
Methodologieën............................................................................................................................7
Gestructureerd vs object-georiënteerd ontwerp..........................................................................7
Hoofdstuk 2: Variabelen en Datastructuren........................................................................8
Constanten...................................................................................................................................8
Variabelen....................................................................................................................................8
Declarate......................................................................................................................................8
Initalisate.....................................................................................................................................9
Toekenning...................................................................................................................................9
Basistypes.....................................................................................................................................9
Integer...........................................................................................................................................9
Real.............................................................................................................................................10
Char en string..............................................................................................................................10
Boolean.......................................................................................................................................10
Datastructuren...........................................................................................................................10
Arrays..........................................................................................................................................10
Records.......................................................................................................................................11
Hoofdstuk 3: Basisstructuren............................................................................................11
Sequente...................................................................................................................................11
Iterate........................................................................................................................................11
For…next.....................................................................................................................................12
Repeat… untl..............................................................................................................................12
While…........................................................................................................................................12
Selecte.......................................................................................................................................12
If… then.......................................................................................................................................13
Switch..........................................................................................................................................13
Hoofdstuk 4: Procedures..................................................................................................13
Wat zijn procedures....................................................................................................................13
Functe........................................................................................................................................13

, Globale en lokale variabele.........................................................................................................13
Parameters..................................................................................................................................14
Recursiviteit...............................................................................................................................14
Voordelen van procedures.........................................................................................................14
Hoofdstuk 6: Sofwarekwaliteit........................................................................................15
Kwaliteit.....................................................................................................................................15
Kwaliteitseisen...........................................................................................................................15
Afweging tussen kwaliteitseisen.................................................................................................16
Verband met onderhoud............................................................................................................17
Verband met architectuur..........................................................................................................17
Hoofdstuk 7: Modules......................................................................................................17
Modules.....................................................................................................................................17
Definite.......................................................................................................................................17
Communicate.............................................................................................................................18
Kenmerken..................................................................................................................................18
Ontwerpen met modules: Voordelen.........................................................................................18
Bepalen van modules..................................................................................................................19
IVO-architectuur.........................................................................................................................19
Koppeling...................................................................................................................................19
Cohesie.......................................................................................................................................21
Hoofdstuk 9: Inleiding tot Object-oriëntate.....................................................................22
Inleiding......................................................................................................................................22
Abstract Data Type (ADT)...........................................................................................................22
Object-Oriëntate.......................................................................................................................23
Objecten en Klassen....................................................................................................................23
Attributen en methoden.............................................................................................................23
Voordelen van OO.......................................................................................................................23
Inkapseling.................................................................................................................................23
Parameters in Java......................................................................................................................24
UML............................................................................................................................................24
Objecten identiceren................................................................................................................24
Modulariteit en object-oriëntate...............................................................................................25
Hoofdstuk 10: Relates tussen klassen..............................................................................26
Associate...................................................................................................................................26
Generalisate..............................................................................................................................27
Aggregate..................................................................................................................................27
Hoofdstuk 11: Eigenschappen van Object-oriëntate.........................................................27
Overerving..................................................................................................................................27
Polymorisme.............................................................................................................................28
Statsche Atributen en Methoden.............................................................................................30
Hoofdstuk 12: Patronen....................................................................................................30
Ontwerppatronen.......................................................................................................................30
Voordeel.....................................................................................................................................30
Voorbeelden...............................................................................................................................31




2 Klaas Van Hoeck 2017-2018

,Hoofdstuk 1: Wat is systeemontwerp?

Inleiding

Informatesystemen
 Leerdoel: Vaardigheid aanleren van hoogstaand IS
 Een informatesysteem
o Staat in voor input, verwerking, opslaan en de uitvoer i.f.v. de
informatebehoeften
o Verzorgt verwerking van grote hoeveelheid data, relatef eenvoudige
verwerking naar output.
o Bestaat uit software, hardware, gebruikers, bedrijfsprocessen, het gebruik
ervan dus niet enkel hardware en software Socio-technische benadering)
 Soorten informate
o Gestructureerde: getallen, tekstuele gegevens, …
o Semigestructureerd: e-mail, documenten, …
o Ongestructureerde: video, audio, afeeldingen
 Soorten verwerking
o Sorteren
o Aggregate
o Selecte
o …


Organisates en IS
 IS bestaat enkel binnen bepaalde context
 Organisate bepaald
o Bedrijfsprocessendus informatebehoeften dus welke IS nodig
 Soorten IS
o Wordt bepaald door plaats in organisate
o TPS
 Kern van systeem
 Doet transactes
 Behandelen atomaire deeltjes bv. 1 inschrijving)
o MIS




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,  Ondersteunen gestructureerde beslissingen
 Bv. Hoeveel studenten per richtng?
o DSS
 Ondersteunen semigestructureerde beslissingen
 Analyseren data ook
 O.b.v. kwanttateve modellen en sensitviteitsanalyse
 Al ingewikkeldere verwerkingen
 Sociale kant is ook belangrijk om het ontwerp van IS te laten slagen
 Bouwen van IS is socio-technisch project
o Nieuwe bedrijfsprocessen
o Nieuwe hiërarchieën van bevoegdheden
o Nieuwe taken voor WN
o Nieuwe machtsverhoudingen
o ICT moet juiste systemen bouwen


Software engineering
 Ontstaan ’60 in de softwarecrisis
o Programmeren was afankelijk van individu
 Gebeurden ad hoc
o Geen structuur
 Spaghetticode
o Resultaat
 Slechte leesbaarheid
 Veel fouten
 Slechte onderhoudbaarheid
 Term verwijst naar de discipline van het ontwerpen, ontwikkelen en onderhouden
van software op basis van
o Principes
o Methodologieën
o Methodes
o Technieken
o Om kwalitatef hoogstaande software te maken
 Gericht op grote systemen
 Streven naar
o Uniformiteit
o Standaardisate
o Betrouwbaarheid
o Onderhoudbaarheid
 Technieken en methodes geleend uit andere wetenschappen




4 Klaas Van Hoeck 2017-2018