FIT 2001 Lecture
Actually lecture was interesting this time, since it was domain modelling. A model drawn with as little implementation information as possible to describe a system to be implemented.
To describe things in a system, that is modelling. Modelling is very important to create a plan or roadmap to imagine the end system. It fits all the requirements into understandable blocks so that there is an organized plan to build the system.
Well if you fail to plan then you plan to fail.
In an object orientated approach, the things are objects with their classes governing the objects blue print.
Class : Type of Thing
Object: The Thing
Method: Behavior of the Thing
Attributes : Descriptive values of the thing
A method I picked up is identifying the nouns and verbs. Nouns for things and verbs for functions of those things. These help make the domain model tangible.
Cardinality / Multiplicity describes the relationship between objects with each other. An example would be a single hospital to multiple departments would have a cardinality of 1 at hospital and 0..* at departments. The '*' character represents many.
Unified Modelling Language is a tool used to model systems. In an object orientated approach, classes, attributes and methods fill most of the domain modelling.Still new to this way of modelling and hence lacking a bit of the rules.
FIT 2001 Tute
A sub-class and a super-class share the amount of attributes of their objects. This is due to inheritance. This is a form of generalization.
Describing multiplicities, describes associations. The way objects relate to each other, that was how I interpret it. This description helps the developer, understand the relationships between the classes and their neighbouring classes.
Aggregation or whole-part relationships are relationships that relate objects to its parts. Like a car has an engine and multiple other components.
There was one question with the problem of creating a student, teacher , professor system. The question was why would the Human Resource Committee be omitted from the system. I found that it was not the main point of the system problem being described but maybe it was due more to the description of the human resource committee was incomplete and thus with not enough information, you do not go include into the system an unclear object. An unclear object increases the complexity and the requirements may not be met and hence wasted money and time.
Visual Paradigm is an interesting tool. I was fussing with it since it doesn't work like an ordinary drawing tool where you can just draw lines all over the place. Instead the links are quite specific with generalization lines and aggregation lines to link the classes together. Compared to other visual tools though, I felt like the tool was a bit complex. One thing I do like about the tool though is that it works by projects so I can have multiple diagrams all in a single file instead of image files every where around my computer.
Until my next blog
You're doing a good job of summarising the lectures and tutes. I find this useful as I don't go to them (I'm off campus). I'll check back once in a while. Thanks for a good read.
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