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3 years ago

5

Do you ever just . . . . . . . . . . . . .

Computers and Technology

2 answers:

eduard3 years ago

6 0

Answer:

Ok than taste in art is immaculent amazing wonderful

Nezavi [6.7K]3 years ago

4 0

Answer:

sure? *confusion*

Explanation:

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Teenagers and their parents will never understand each other-the generation gap is too big. Its for my grade 11 English speech

bazaltina [42]

Answer:

lol

Explanation:

lol

7 0

3 years ago

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Which of the following class definition defines a legal abstract class Group of answer choices public class Rectangle abstract {

valkas [14]

<h2>Question</h2>

Which of the following class definition defines a legal abstract class Group of answer choices

(a)

public class Rectangle abstract {

public abstract double findArea ( );

}

(b)

public abstract class Rectangle {

public abstract double findArea ( );

}

(c)

public class Rectangle {

public abstract double findArea ( );

}

(d)

public class abstract Rectangle {

public abstract double findArea ( );

}

<h2>Answer:</h2>

(b)

public abstract class Rectangle {

public abstract double findArea ( );

}

<h2>Explanation:</h2>

When a class is declared with the abstract keyword, the class is called an abstract class. Abstract classes cannot be instantiated and may include one or more abstract methods. If a class contains an abstract method, then it (the class) must be declared abstract.

In Java, abstract classes are defined using the following format:

<em>[access_modifier]</em> abstract class <em>[name_of_class]</em>

[access_modifier] specifies the access modifier of the class which could be public, private, e.t.c

abstract is the keyword that specifies that the class is an abstract class.

class is a keyword used for defining classes

name_of_class specifies the name of the class.

The only option that fulfils this format is <em>option b</em> where;

(i) The access modifier is public

(ii) The name of the class is Rectangle

Option a is not correct because the <em>abstract</em> keyword is supposed to come before the <em>class</em> keyword.

Option c is not correct because the keyword <em>abstract</em> is missing. In other words, the class must be declared abstract since it contains abstract method findArea();

Option d is not correct because the <em>abstract</em> keyword is supposed to come before the <em>class</em> keyword.

7 0

3 years ago

PLEASE HELP !!!! WILL UPVOTE

Gemiola [76]

The answer to this is C :D

5 0

3 years ago

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When installing a Windows 10 an already installed Windows 7 what happen

astra-53 [7]

Answer:

are u updating it? or u r rooting it?

4 0

3 years ago

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[1] Please find all the candidate keys and the primary key (or composite primary key) Candidate Key: _______________________ Pri

AVprozaik [17]

Answer:

Check the explanation

Explanation:

1. The atomic attributes can't be a primary key because the values in the respective attributes should be unique.

So, the size of the primary key should be more than one.

In order to find the candidate key, let the functional dependencies be obtained.

The functional dependencies are :

Emp_ID -> Name, DeptID, Marketing, Salary

Name -> Emp_ID

DeptID -> Emp_ID

Marketing -> Emp_ID

Course_ID -> Course Name

Course_Name -> Course_ID

Date_Completed -> Course_Name

Closure of attribute { Emp_ID, Date_Completed } is { Emp_ID, Date_Completed , Name, DeptID, Marketing, Salary, Course_Name, Course_ID}

Closure of attribute { Name , Date_Completed } is { Name, Date_Completed , Emp_ID , DeptID, Marketing, Salary, Course_Name, Course_ID}

Closure of attribute { DeptID, Date_Completed } is { DeptID, Date_Completed , Emp_ID,, Name, , Marketing, Salary, Course_Name, Course_ID}

Closure of attribute { Marketing, Date_Completed } is { Marketing, Date_Completed , Emp_ID,, Name, DeptID , Salary, Course_Name, Course_ID}.

So, the candidate keys are :

{ Emp_ID, Date_Completed }

{ Name , Date_Completed }

{ DeptID, Date_Completed }

{ Marketing, Date_Completed }

Only one candidate key can be a primary key.

So, the primary key chosen be { Emp_ID, Date_Completed }..

2.

The functional dependencies are :

Emp_ID -> Name, DeptID, Marketing, Salary

Name -> Emp_ID

DeptID -> Emp_ID

Marketing -> Emp_ID

Course_ID -> Course Name

Course_Name -> Course_ID

Date_Completed -> Course_Name

3.

For a relation to be in 2NF, there should be no partial dependencies in the set of functional dependencies.

The first F.D. is

Emp_ID -> Name, DeptID, Marketing, Salary

Here, Emp_ID -> Salary ( decomposition rule ). So, a prime key determining a non-prime key is a partial dependency.

So, a separate table should be made for Emp_ID -> Salary.

The tables are R1(Emp_ID, Name, DeptID, Marketing, Course_ID, Course_Name, Date_Completed)

and R2( Emp_ID , Salary)

The following dependencies violate partial dependency as a prime attribute -> prime attribute :

Name -> Emp_ID

DeptID -> Emp_ID

Marketing -> Emp_ID

The following dependencies violate partial dependency as a non-prime attribute -> non-prime attribute :

Course_ID -> Course Name

Course_Name -> Course_ID

So, no separate tables should be made.

The functional dependency Date_Completed -> Course_Name has a partial dependency as a prime attribute determines a non-prime attribute.

So, a separate table is made.

The final relational schemas that follows 2NF are :

R1(Emp_ID, Name, DeptID, Marketing, Course_ID, Course_Name, Date_Completed)

R2( Emp_ID , Salary)

R3 (Date_Completed, Course_Name, Course_ID)

For a relation to be in 3NF, the functional dependencies should not have any transitive dependencies.

The functional dependencies in R1(Emp_ID, Name, DeptID, Marketing, Date_Completed) is :

Emp_ID -> Name, DeptID, Marketing

This violates the transitive property. So, no table is created.

The functional dependencies in R2 ( Emp_ID , Salary) is :

Emp_ID -> Salary

The functional dependencies in R3 (Date_Completed, Course_Name, Course_ID) are :

Date_Completed -> Course_Name

Course_Name -> Course_ID

Here there is a transitive dependency as a non- prime attribute ( Course_Name ) is determining a non-attribute ( Course_ID ).

So, a separate table is made with the concerned attributes.

The relational schemas which support 3NF re :

R1(Emp_ID, Name, DeptID, Course_ID, Marketing, Date_Completed) with candidate key as Emp_ID.

R2 ( Emp_ID , Salary) with candidate key Emp_ID.

R3 (Date_Completed, Course_Name ) with candidate key Date_Completed.

R4 ( Course_Name, Course_ID ). with candidate keys Course_Name and Course_ID.

6 0

3 years ago