List the various data abstraction concepts and the corresponding modeling concepts in the EER model.

amanf
2021-09-11
Answered

List the various data abstraction concepts and the corresponding modeling concepts in the EER model.

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doplovif

Answered 2021-09-12
Author has **71** answers

Here is a list of data abstraction concepts and their variants in EER model:

* Classification and instantiation - The EER variant of classification is represented by classifying entities into entity types based on their attributes and relationships. Relationship instances becomerelationship types. Forthe need offurther classification, we introduce superclass /subclass concepts and sometimes even categories. In EER model, there is no handling of class exceptions and no showing of examples (instances).

* Identification - EER model implements identification hy sticking to the rule of name uniqueness. Every entity type, relationship type, attribute, subclass, superclass and category has to have unique name that no other object in database has.

* Specialization and Generalization - The concept of specialization and generalization in the EER model is represented by subclasses. They are more specific objects than their respective superclasses and arerelated to them by IS-A-SUBCLASS-OF (or shortly IS-A) relationship.

* Aggregation and Association - EER schema uses aggregation abstraction in form of creating new compositeobjects. We can aggregate attributes to createa composite attribute, entity type or even a relationship type if there’s need to. Association in EER modeling is simply a relationship type between two or more independent entity types.

* Classification and instantiation - The EER variant of classification is represented by classifying entities into entity types based on their attributes and relationships. Relationship instances becomerelationship types. Forthe need offurther classification, we introduce superclass /subclass concepts and sometimes even categories. In EER model, there is no handling of class exceptions and no showing of examples (instances).

* Identification - EER model implements identification hy sticking to the rule of name uniqueness. Every entity type, relationship type, attribute, subclass, superclass and category has to have unique name that no other object in database has.

* Specialization and Generalization - The concept of specialization and generalization in the EER model is represented by subclasses. They are more specific objects than their respective superclasses and arerelated to them by IS-A-SUBCLASS-OF (or shortly IS-A) relationship.

* Aggregation and Association - EER schema uses aggregation abstraction in form of creating new compositeobjects. We can aggregate attributes to createa composite attribute, entity type or even a relationship type if there’s need to. Association in EER modeling is simply a relationship type between two or more independent entity types.

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The function $y=3.5x+2.8$ represents the cost y (in dollars) of a taxi ride of x miles.

a. Identify the independent and dependent variables.

b. You have enough money to travel at most 20 miles in the taxi. Find the domain and range of the function.

a. Identify the independent and dependent variables.

b. You have enough money to travel at most 20 miles in the taxi. Find the domain and range of the function.

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The expression $\frac{\sqrt{7}}{\sqrt{28}}$

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To solve: The problem by modeling and solving a system of linear equations.

asked 2021-09-06

a) To write: A binomial that represents the height of the projection.

Given information: Height of wall is xft. and width of projection is$(x-3)ft$ . Area is represented by ${x}^{2}-8x+15$ .

b) To find: Perimeter of projection when height of the wall is 8ft.

Given information: Height of wall is$x=8ft$ and width of projection is $(x-3)ft$ . Height of projection is $(x-5)ft.$

Given information: Height of wall is xft. and width of projection is

b) To find: Perimeter of projection when height of the wall is 8ft.

Given information: Height of wall is

asked 2021-09-12

Modeling situations as functions is common. Describe whether each description represents a function. Explain.

a. The input is a day of the year. The output is the average temperature in Barcelona on that day.

b. The input is speed of a car. The output is the time it takes for a car moving constantly at that speed to travel 100 miles.

c. The input is a positive number. The output is a number whose absolute value is the input.

d. The input is a year. The output is the population of the United States during that year.

a. The input is a day of the year. The output is the average temperature in Barcelona on that day.

b. The input is speed of a car. The output is the time it takes for a car moving constantly at that speed to travel 100 miles.

c. The input is a positive number. The output is a number whose absolute value is the input.

d. The input is a year. The output is the population of the United States during that year.

asked 2021-09-08

a) To calculate: A model of the form $N\left(t\right)=a+b\mathrm{ln}t$ for the provided data.

b) To calculate: The sales in a 7 weeks.

c) The validity of the statement with explanation.

b) To calculate: The sales in a 7 weeks.

c) The validity of the statement with explanation.