0
"An entity is a person, place, event, or thing about which data is collected...An instance is an occurence of an entity." - Systems Analysis & Design (4th) - Dennis
An example of this would be STUDENT as the entity while JACK SMITH is an instance of that entity.
If an entity is an individual "person, place, event, or thing about which data is collected", then an entity is an instance. Linguistically, entity is just another word for a single thing ("The existence of a thing as contrasted with its attributes.", Merriam-Webster's On-line Dictionary). Entities that have the same attributes are grouped in what are best called entity classes (it doesn't make sense to refer to a collection of entities as an entity). Entity and entity class are data modeling terms. The corresponding object modeling terms are object and class, albeit that a class typically has operations, which are foreign to an entity class.
Still curious? Ask our experts.
Chat with our AI personalities
Devin
Fran
BlakeAdd your answer:
Earn +20 pts
What is the difference between use cases and class diagrams?
The main difference between use cases and class diagrams is that a diagram shows how data is related. On the other hand, use cases show how a user uses a system.
What is the difference between integrated algebra and algebra 1?
Algebra 1 is a class/course that is on a higher level than Algebra.
What is the difference between analogy and example as amethod of teaching?
There is no difference as they are both used for simplifying complex stuff used somewhat as explanations during lessons. An example is a representation of a class or a group of things, while an analogy is a comparison made for clarifying between two or more dissimilar things. For example, an analogy about ecosystems would be something like a class room consisting of several students of different races. An example about ecosystems would be something like a tropical rainforest ofr a pond
What is the class midpoint?
midpoint between 4-16
What is the difference between a specialization hierarchies and specialization lattices?
Specialization Hierarchy - has the constraint that every subclass participates asa subclass in only one class/subclass relationship, i.e. that each subclass hasonly one parent. This results in a tree structure.Specialization Lattice - has the constraint that a subclass can be a subclass of morethan one class/subclass relationship.
