All categories

3 years ago

Normalize the following relation:

Computers and Technology

1 answer:

lora16 [44]3 years ago

5 0

Answer:

Hi Riahroo! This is a good question on the concept of relational databases.

We can normalize the relations as follows:

Flight

(flightnumber (unique), flighttime, airline_id, departure_city, arrival_city, passenger_id, pilot_id, airplane_id)

has_one_and_belongs_to :airline

has_many :passengers

has_one :pilot

Itinerary(passenger_id, flight_id)

Belongs_to

Passenger_details

(passengername (unique), gender, date_of_birth)

has_many :flights

Pilot

(pilotname (unique), gender, date_of_birth)

has_many :flights

airline(airlinename)

airplane(planeID, type, seats))

Explanation:

To normalize a relation, we have to remove any redundancies from the relationships between database objects/tables and simplify the structure. This also means simplifying many-to-many relationships. In this question, we see there is a many-to-many relationship between flights and passengers. To resolve this we can introduce a join table which simplifies this relationship to a one-to-many between the objects.

You might be interested in

g What advantage does a circuit-switched network have over a packet-switched network? What advantages does TDM have over FDM in

REY [17]

Answer:

Advantages of a circuit-switched network over a packet-switched network are:

In Circuit-switched networks, resources needed to provide communication between the end systems for the duration of the session are usually reserved unlike in packet-switched networks where they are not reserved.
Circuit-switched networks have faster communication, so they can be used for Voice/Video calls
Circuit-switched networks have less errors in communication
Circuit-switched networks are more suitable for real-time services. Packet-switched networks are simpler, more efficient, and less costly to implement. They also offer better sharing of transmission capacity than circuit-switched network

Advantages does TDM have over FDM in a circuit-switched network are;

In TDM, all connections operate at the same frequency , but In FDM, all connections operate at different frequencies
In TDM there is low interference between the signals that are being multiplexed as compared to FDM.
In TDM, bandwidth is saved by allocating time slots on demand dynamically
TDM systems are more flexible than FDM

4 0

3 years ago

Read 2 more answers

Brad Smith works for GHI Firm. GHI firm is a registered Broker-Dealer in State A, B and C and a registered IA in State A. Brad i

Rashid [163]

Answer:

The correct answer is B. This is unacceptable because Brad is not registered in State B

Explanation:

Given:

Brad is a registered Investment Advisory Representative (IAR) in State A.

In the question, it's not stated that Brad is not registered in State B.

Setting up an office in State B is unacceptable because Brad is holding himself out as an IAR in State B and he is not registered as an IAR in State B.

Though GHI is a registered firm in State B, Brad also needs to be registered before setting up an office in other states.

8 0

3 years ago

What is the output of this code? import java.util.HashSet; class A { public static void main(String[ ] args) { HashSet set = new

kompoz [17]

Answer:

The code will give an error that is "At least one public class is required in main file".

Explanation:

In the given code if we do not use the public access modifier to the class. It will give an error so, the correct code to this question as follows:

Program:

import java.util.HashSet; //import package

public class A //define class as public.

{

public static void main(String[ ] args) //define main method.

{

HashSet set = new HashSet(); //creating hashset object.

set.add("A"); //add alphabet in hashset

set.add("B"); //add alphabet in hashset

set.add("C"); //add alphabet in hashset

System.out.print("Size of HashSet is :"set.size()); //print the size of hashset.

}

Output:

Size of HashSet is : 3

Explanation of the program:

In the above program, we define a public class that is "A" and inside the class, we define the main method.

Inside the main method, we create a HashSet class object that is "set".

To add elements in HashSet we use add() function that adds elements and in the last, we use the size() function that prints the size HashSet.

5 0

3 years ago

The true or false questions.

DIA [1.3K]

Answer:

true

Explanation:

The command:

find -empty -type f -exec rm { } \;

carries out the following steps.

1) Finds all the empty files in the current directory and its subdirectories.

2) For each of the identified files, it executes the command specified as the parameter to exec option,namely, rm <filename>.

So effectively it removes all empty files in the directory tree starting at the current directory.

7 0

3 years ago

Readability is the level of vocabulary used on the page. True or false

konstantin123 [22]

Answer:

FALSE....john has no idea what hes talking about. i knew this was false yet i looked it up and got it wrong anyway because of john its freaking false

Explanation:

8 0

3 years ago