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Liono4ka [1.6K]
2 years ago
8

You need to design a data storage scheme for Hayseed Heaven library data system. There are several hundred thousand large data r

ecords. You expect frequent insertions/deletions as well as frequent queries, involving multiple attributes. There is no requirement for printing the file in order. You may assume the initial file is available sorted. The queries are in real time and primarily occur on the ISBN number, title, and author fields. There are occasional queries on the publisher and subject fields of the record. You may make reasonable assumptions about hardware availability. The entire system is archived monthly. What do you propose and why
Computers and Technology
1 answer:
Alekssandra [29.7K]2 years ago
7 0

Answer:

Make use of hash tables

Explanation:

The appropriate thing to use for this should be a hash table.

A Hash Table can be described as a data structure which stores data in an associative manner. In a hash table, data is stored in an array format, where each data value has its own unique index value. Access of data becomes very fast if we know the index of the desired data. So we can perform Hashing on ISBN Number since its unique and based on the Hash Function w ecan store the Information record.

There is no requirement for printing the file in order - HashTables dont store the data in order of insertions, so no problems with that

It becomes a data structure in which insertion and search operations are very fast irrespective of the size of the data. So Querying books details can be fast and searching will take less time.

It can also be pointed out that it wont be too expensive for Hardware implemtation as HashTables stores data based on Hash Functions and memory consumption is also optimal which reduces memory wastages.

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A blood bank maintains two tables - DONOR, with information about people who are willing to donate blood and ACCEPTOR, with info
Kipish [7]

Answer:

The sql query is given below.

Since we need to count of males and females for a particular blood group, we put xxx for the blood group.

SELECT COUNT(SELECT DID FROM DONOR WHERE GENDER LIKE "M%") as Male_Donors,

COUNT(SELECT DID FROM DONOR WHERE GENDER LIKE "F%") as Female_Donors

FROM DONOR

WHERE BG = xxx;

Explanation:

The clauses in the query are as follows.

1. SELECT: all the columns required in the output are put in this clause.

2. FROM JOIN ON: the table(s) from which the above columns are taken are put in this clause.

3. WHERE: any condition required to filter the output is put in this clause.

The query is explained below.

1. Find the number of male donors. Number of anything can be found using COUNT() function. A query is required since gender is included in deciding the type of donor.

2. The query is defined to find number of male donors as follows.

COUNT( SELECT DID FROM DONOR WHERE GENDER LIKE "M%"; )

3. In the previous query, LIKE operator is used since it is not defined what value is stored for male donors.

4. Similarly, the query to find the number of female donors is formed.

COUNT( SELECT DID FROM DONOR WHERE GENDER LIKE "F%"; )

5. Next, the final query is formed as follows.

SELECT: both COUNT() functions will come here.

FROM: table name

WHERE: specific blood group will be put here

GROUP BY: this clause is optional and is not used in this query.

HAVING: this clause is optional and is not used in this query.

6. The query after putting all clauses is shown below.

SELECT COUNT(SELECT DID FROM DONOR WHERE GENDER LIKE "M%"),

COUNT(SELECT DID FROM DONOR WHERE GENDER LIKE "F%")

FROM DONOR

WHERE BG = xxx;

7. Alias is used in the above query for each column to get the final query.

SELECT COUNT(SELECT DID FROM DONOR WHERE GENDER LIKE "M%") as Male_Donors, COUNT(SELECT DID FROM DONOR WHERE GENDER LIKE "F%") as Female_Donors

FROM DONOR

WHERE BG = xxx;

7 0
2 years ago
9. Which of the following are true for all regular languages and all homomorphisms? (a) h (L1 ∪ L2)= h (L1) ∩ h (L2). (b) h (L1
mixer [17]

Answer:

h (L1 ∪ L2)= h (L1) ∩ h (L2).

This is true.

There will be w ∈  (L1 ∪ L2) for any s ∈ h (L1 ∪ L2) in such a way that s=h(w)

we can assume that w ∈ L1

So In this case h(w) ∈ L (S1). Hence s ∈ L(S1)

for any s ∈ h (L1) U h(L2)

We can assume that s ∈ L(S1)

There exists w ∈ L1 such that s= h(w)

In this case it is w ∈ L1 U L2 as well.

Hence , s ∈ h (L1 U L2)

Explanation

consider  = 0,1 and  = a,b and h(0) = a , h(1) = ab

(a) Consider L1 = 10,01 and L2 = 00,11

   Now L1 ∪ L2 = 00,01,10,11

   h (L1 ∪ L2) = h(00) , h(01) , h(10) , h(11) = h(0)h(0) , h(0)h(1) , h(1)h(0) , h(1)h(1)

  = aa, aab , aba , abab

Hence h (L1 ∪ L2) = aa, aab , aba , abab .

Here h (L1) = h(10) , h(01) = h(1)h(0) , h(0)h(1) = aba , aab

Hence h (L1) = aba , aab .

Here h (L2) = h(00) , h(11) = h(0)h(0), h(1)h(1) = aa, abab

Hence h(L2) = aa, abab.

Finally Hence , h (L1 ∪ L2)= h (L1) ∩ h (L2).

5 0
2 years ago
Thelma is a web developer for a bowling league. She wants visitors to the website to be able to print web pages, such as league
prohojiy [21]

Answer:

"@page" is the correct answer for the above question.

Explanation:

  • "@page" is a syntax of CSS which will affect that page which is converted from the hard copy from the soft copy. It means it affects the page which will render the output.
  • So If the Thelma wants to set the margins on the output page then he can do this by the help of the "@page" tag which is defined in the CSS, and then the margin is set to this tag by the help of margin statement.
8 0
2 years ago
Write an expression that continues to bid until the user enters 'n'.
alisha [4.7K]

Answer:

1)

Add this while statement to the code:

while(keep_going!='n'):  

#the program keeps asking user to continue bidding until the user enter 'n' to stop.

2)

Here is the code for ACTIVITY 53.3. While loop: Insect growth:

num_insects = int(input())

while num_insects <= 100:

   print(num_insects, end=' ')

   num_insects = num_insects * 2

 

Explanation:

Here is the complete code for 1)

import random

random.seed (5)

keep_going='-'

next_bid = 0

while(keep_going!='n'):

   next_bid = next_bid + random.randint(1, 10)

   print('I\'ll bid $%d!' % (next_bid))

   print('continue bidding?', end='')

   keep_going = input()

Here the the variable keep_going is initialized to a character dash keep_going='-'

The statement keep_going = input() has an input() function which is used to take input from user and this input value entered by user is stored in keep_going variable. while(keep_going!='n'):  is a while loop that keeps iterating until keep_going is not equal to 'n'.    print('continue bidding?', end='')  statement prints the continue bidding? message on the output screen. For example the user enters 'y' when this message appears on screen. So keep_going = 'y' . So the operation in this statement next_bid = next_bid + random.randint(1, 10) is executed in which next_bid is added to some randomly generated integer within the range of 1 to 10 and print('I\'ll bid $%d!' % (next_bid))  prints the result on the screen. Then the user is prompted again to continue biffing. Lets say user enters 'n' this time. So keep_going = 'n'. Now the while loop breaks when user enters 'n' and the program ends.

2)

num_insects = int(input()) #the user is prompted to input an integer

while num_insects <= 100: #the loop keeps iterating until value of num_insects exceeds 100

   print(num_insects, end=' ') #prints the value of num_insects  

   num_insects = num_insects * 2 #the value of num_insects is doubled

For example user enters 8. So

num_insects = 8

Now the while loop checks if this value is less than or equal to 100. This is true because 8 is less than 100. So the body of while loop executes:

   print(num_insects, end=' ') statement prints the value of num_insects

So 8 is printed on the screen.

num_insects = num_insects * 2 statement doubles the value of num_insects So this becomes:

num_insects = 8 * 2

num_insects = 16

Now while loop checks if 16 is less than 100 which is again true so next 16 is printed on the output screen and doubled as:

num_insects = 16 * 2

num_insects = 32

Now while loop checks if 32 is less than 100 which is again true so next 32 is printed on the output screen and doubled as:

num_insects = 32 * 2

num_insects = 64

Now while loop checks if 64 is less than 100 which is again true so next 64 is printed on the output screen and doubled as:

num_insects = 64 * 2

num_insects = 128

Now while loop checks if 128 is less than 100 which is false so the program stops and the output is:

8 16 32 64  

The programs along with their output is attached.

7 0
2 years ago
Write a program for determining if a year is a leap year. In the Gregorian calendar system you can check if it is a leaper if it
SOVA2 [1]

Answer:

def leap_year_check(year):

return if int(year) % 4 == 0 and (int(year) % 100 != 0 or int(year) % 400 == 0)

Explanation:

The function is named leap_year_check and takes in an argument which is the year which we wish to determine if it's a new year or not.

int ensures the argument is read as an integer and not a float.

The % obtains the value of the remainder after a division exercise. A remainder of 0 means number is divisible by the quotient and a remainder other wise means it is not divisible by the quotient.

If the conditions is met, that is, (the first condition is true and either the second or Third condition is true)

the function leap_year_check returns a boolean ; true and false if otherwise.

8 0
2 years ago
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