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Marianna [84]
2 years ago
6

Short notes on primary key​

Computers and Technology
1 answer:
Thepotemich [5.8K]2 years ago
5 0

Answer:

A primary key is a special relational database table column (or combination of columns) designated to uniquely identify each table record. A primary key is used as a unique identifier to quickly parse data within the table. A table cannot have more than one primary key.

Primary Key.

Candidate Key.

Alternate Key.

Super Key.

Composite Key.

Foreign Key.

Unique Key.

In the relational model of databases, a primary key is a specific choice of a minimal set of attributes that uniquely specify a tuple in a relation. Informally, a primary key is "which attributes identify a record," and in simple cases constitute a single attribute: a unique ID.

Explanation:

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Answer:

Here is the script:  

function dd = functionDMS(dd)  

prompt= 'Enter angle in DD form ';

dd = input(prompt)

while (~checknum(dd))

if ~checknum(dd)

error('Enter valid input ');

end

dd = input(prompt)

end  

degrees = int(dd)

minutes = int(dd - degrees)

seconds = ( dd - degrees - minutes / 60 ) * 3600  

print degrees

print minutes

print seconds

print dd

Explanation:

The script prompts the user to enter an angle in decimal degree (DD) form. Next it stores that input in dd. The while loop condition checks that input is in valid form. If the input is not valid then it displays the message: Enter valid input. If the input is valid then the program converts the input dd into degrees, minutes and seconds form. In order to compute degrees the whole number part of input value dd is used. In order to compute the minutes, the value of degrees is subtracted from value of dd. The other way is to multiply remaining decimal by 60 and then use whole number part of the answer as minutes. In order to compute seconds subtract dd , degrees and minutes values and divide the answer by 60 and multiply the entire result with 3600. At the end the values of degrees minutes and seconds are printed. In MATLAB there is also a function used to convert decimal degrees to degrees minutes and seconds representation. This function is degrees2dms.

Another method to convert dd into dms is:

data = "Enter value of dd"

dd = input(data)

degrees = fix(dd);

minutes = dd - degrees;

seconds = (dd-degrees-minutes/60) *3600;

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It would depend on the movie and the theater policy.....

Hope this helps have a good day

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