Which process could you use to add a table to a document?

[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

Two technicians are discussing the lower-end operation of an engine. Technician A says that power loads result from the expansio

notka56 [123]

Answer:

It's Both are correct.

Explanation:

I've taken test

6 0

3 years ago

XYZ Corp.’s facilities in Nashua, New Hampshire, are two office buildings 400 feet apart, each with its own LAN. To connect the

damaskus [11]

Answer:

a: Twisted pair won't span a 400-foot distance.

Explanation:

The maximum distance that twisted pair cables can support without attenuation is 100 meters which is approximately 328 feet and the two office buildings are 400 feet apart, so it is useless to install a twisted pair cable for such a large distance. A much better option would be to install optic fiber. Though it is a bit expensive but it is the best option in this case.

Hence option (a) is the correct reason for installing an optic fiber cable rather than a twisted pair cable.

6 0

3 years ago

To determine why a computer program started to function differently, Mel should most likely use data to

Amiraneli [1.4K]

Answer:

convince the software company of the issue

Explanation:

3 0

3 years ago

Read 2 more answers

Assignment Background Video games have become an outlet for artists to express their creative ideas and imaginations and a great

Sphinxa [80]

Answer:

Code

import csv

def open_file():

try:

fname=input("Enter the filename to open (xxx.yyy): ")

fp=open(fname,encoding='utf-8')

return fp

except FileNotFoundError:

print("File not found! Please Enter correct filename with extension")

return open_file()

def read_file(fp):

fields = []

rows = []

csvreader = list(csv.reader(fp))

# skiped 1 row because it contains field name

fields = csvreader[0]

D1={}

D2={}

D3={}

# accessing the data of csv file

for line in csvreader[1:]:

name = line[0].lower().strip()

platform = line[1].lower().strip()

if line[2]!='N/A':

year = int(line[2])

else:

year=line[2]

genre = line[3].lower().strip()

publisher = line[4].lower().strip()

na_sales = float(line[5])

eur_sales = float(line[6])

jpn_sales = float(line[7])

other_sales = float(line[8])

global_sales=(na_sales+eur_sales+jpn_sales+other_sales)*1000000

if name not in D1:

D1[name]=[]

D1[name].append((name, platform, year, genre, publisher,global_sales))

if genre not in D2:

D2[genre]=[]

D2[genre].append((genre, year, na_sales, eur_sales,jpn_sales, other_sales, global_sales))

if publisher not in D3:

D3[publisher]=[]

D3[publisher].append((publisher, name, year, na_sales,eur_sales, jpn_sales, other_sales, global_sales))

# sorting

temp={}

# sorting keys

for Keys in sorted (D1) :

ls=D1[Keys]

ls=sorted(ls,key=lambda x: x[-1]) # sorting values

temp[Keys]=ls

D1=temp.copy()

temp={}

# sorting keys

for Keys in sorted (D2) :

ls=D2[Keys]

ls=sorted(ls,key=lambda x: x[-1]) # sorting values

temp[Keys]=ls

D2=temp.copy()

temp={}

# sorting keys

for Keys in sorted (D3) :

ls=D3[Keys]

ls=sorted(ls,key=lambda x: x[-1]) # sorting values

temp[Keys]=ls

D3=temp.copy()

return D1,D2,D3

def main():

fp=open_file()

D1,D2,D3=read_file(fp)

# displaying the row_count in dictionaries

cnt=0

for d in D1:

cnt+=1

print(cnt)

print("\n\n=============================================\n\n")

cnt=0

for d in D2:

cnt+=1

print(cnt)

print("\n\n=============================================\n\n")

cnt=0

for d in D3:

cnt+=1

print(cnt)

print("\n\n=============================================\n\n")

if __name__=="__main__":

main()

Explanation:

see code and see output attached

7 0

3 years ago