LESSON-2 DATABASE ARCHITECTURES (Cont’d; Ashraf, Khan, and Mir)
LESSON-2 DATABASE ARCHITECTURES (Cont’d; Ashraf, Khan, and Mir)
2. Components Of Business Systems
2.1 Overview
A framework of business system helps to understand communicate requirements is called model.
Model explicitly represents structure (syntactical diagrams) and functional behavior (semantically business processes).
These model diagrams make qualitative guesses about the attributes and behavior of the actual system.
These are called object technologies.
The model consists of objects (entities) and the relations among them.
The analysis phase produces these entities.
The entities are the packages of the data (attributes).
These attributes are associated with procedures specific to each object that is called access method (method), to describe the behavior of the object.
The package should be accessed through these methods, is encapsulation that enforces the correct use of data items, because of its meaning (semantics) incorporated through that method.
The methods are invoked to execute an event by a message to an object.
The message includes object’s name and the method, if additional data is needed, that is the argument(s) in the message.
The framework of modeling categorizes the objects; for example, tools; pliers, wrench, screwdriver and so on. This would be called a class.
The class is the description that covering the important attributes.
In object technology a model is usually built with classes and the representation of the real-world are called class instances.
Object and associations (relationships) applied to classes and links when applied to objects.
For instance; A class worker associated with the class tools by the relationship ‘uses’ one-or-more workers may use a tool. This one-or-more abstraction is termed the multiplicity of association. Thus it makes possible to define classes that are the abstraction of the common features of existing classes.
For instance; canned foods, classified advertisement
The common characteristics of the higher-level classes can be ‘inherited’ by the less general classes without repeating, is termed inheritance.
This strategy of model building makes it a general purpose in nature and can be reused in future extensions, this allows drill of producing good quality code, develop and test for the availability of rapid building of prototype is a checkpoint for correct interpretation of user requirements.
The core of an object is a data structure, which provides stable foundations for application development than function’ centered model. Because, the requirement of change are more frequent at the function level than at the data level. Thus, the solution based on a stable higher level, aremore flexible, because it can implement variations of lower level.
Certain development environments (object oriented upper class tools) provide repository of catalogue of classes. That can be used through out application development life cycle. Developers should be able to use generator, language and knowledge based tools to extract the classes from the repository and use them to construct business application from reusable parts.
The object technology (modeling at a higher level) can conceive requirements for faster constructions MIS. Thus, the process of MIS building starts with the abstractions and collection of libraries of reusable classes. These classes are used to construct other models of applications, whose quality can be tested through rapid prototyping.
Click To MAIN PAGE: OBJECT- ORIENTED RELATIONAL MODELLING E-MONOGRAPH, By J. Ashraf, M. Khan, and H. Mir
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- MESSAGE: DEDICATED TO ANONYMOUS COMBATANTS OF KNOWLEDGEمکتب علم الل مہد منل لحد Learning continues from birth to deathFOR PROMOTION OF LEARNEDNESS SHARE WITH FRIENDS ABOUT;
- CAUSE AND EVENTS – SPATIAL And TEMPORAL RESPECTIVELY: https://be4gen.wordpress.com/2012/11/16/cause-and-events-spatial-temporal-respectively/
- WHETHER ‘BRAIN-POWER’ OR ‘HEART-IMPULSE’ PLINTHS ‘HUMAN GEN’? http://sunedu.wordpress.com/2012/09/17/whether-brain-power-or-heart-impulse-plinths-human-gen/
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