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"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.
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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.
What is the difference between the class and the entity?
A class is a type. An entity is a object created from this type. A class is like a definition and the entity behaves as per this definition.
Entity type vs entity instance?
Entity Type : A collection of entities that share common properties or characteristics. for example student is an entity type with common attributes such as student_ID , Name, Class etc. These characteristics are common to all students. Entity Instance: A single occurrence of a particular entity type is called entity instance..
What is the difference between classes and object in C?
An object is an INSTANCE of a class. Human is a class, while YOU are a person, an instance of Human class, but YOU do not represent the entire human class. Or, a class provides the abstraction, and an object is a typical example of that abstraction. Classes provide a blue print to build a real instance of an object.
What is difference between an instance variable and a class variable?
An instance variable is typically associated with an object instance of the class whereas class variable is not associated with any object instance. Static variables are referred to as class variables while non-static regular variables are called instance variables. Simply put, you will have as many instances of the instance variable as there are object instances. i.e., if there are 10 instances of an object, you will have 10 instances of that instance variable as well. But, there will be only one instance of the static or class variable. Instance variables are accessed as follows: objname.variableName; Class variables are accessed as follows: ClassName.variableName;
What is the difference between class variables and instance variables?
In the case of an instance variable, there is one copy for every instance (object). If you create 10 objects based on a class, there will be 10 copies of the variable. A class variable exists only once for the entire class - no matter how many objects you create - or even if you create no objects based on the class. In Java, such variables (class variables) are declared with the statickeyword.
What is the difference between a class method and object in object-oriented C?
Class methods are the member functions that act upon member variables. An object is an instance of a class. C does not support object-oriented programming, but C++ does.
What's the difference between the Class 365 and Class 465 466?
The difference between the Class 365 and Class 465, 466 is basically the cost.
What is the difference between a class method and an instance method?
Instance methods can be called by the object of a Class whereas static method are called by the Class. When objects of a Class are created, they have their own copy of instance methods and variables, stored in different memory locations. Static Methods and variables are shared among all the objects of the Class, stored in one fixed location in memory.Static methods cannotaccess instance variables or instance methods directly-they must use an object reference. Also, class methods cannot use the this keyword as there is no instance for this to refer to.
Difference between exclusive or inclusive class intervals?
difference between inclusive and exclusive class interval
What is entity classes?
same as entity class or entity type or entity set
What is difference between first class and second class on train trips?
What is the difference between buying a 1st class and a 2nd class ticket on the train in England?
What is the difference between a class What is the difference between a class III and class IV hitch and?
class III rated for up to 5,000lbs, class IV is rated for up to 10,000lbs towing capacity
