ENTITY LIFE HISTORIES
iseng - iseng saya bahas disini biar semua orang tahu!!!!!(kaya' penting aja!)
so, what is Entity life hostories?
A major reason for building computer-based information systems is to provide up-to-date and accurate information. Information is constantly changing or evolving, for example the number of beds available in a hospital, the price of petrol, and people's names and addresses. An information system must be able to keep track of these changes. Previous notes have described how the system is modelled from the viewpoint of information flows (DFDs) and from the viewpoint of the information (i.e. entities) that is held (ER modelling).
Entity Life Histories (ELH) model the system from the viewpoint of how the entities/information in a system evolves over time. What the ELHs show is the full set of changes that can possibly occur to the entities/information within the system, together with the context of each change.
Initially, each entity within a system is examined in isolation as this is a manageable unit of information to model. It is the stimuli of the changes that are modelled rather than the entity, a composite picture is formed, eventually specifying the full set of changes that will occur within the system.
An ELH is a diagrammatic representation of the life of a single entity, from its creation to its deletion. The life is expressed as the permitted sequence of events that can cause the entity to change. An event may be thought of as whatever brings a process into action to change entities, so although it is a process that changes the entity, it is the event that is the cause of the change.
Masih dengan tujuan utama yaitu Update - update n update!! chayooo...(FTI - It's works!)
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