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3 years ago

What is a foreign key and how does it provide referential integrity?

Computers and Technology

1 answer:

Step2247 [10]3 years ago

4 0

Answer:

By definition a foreign key of table A is a primary key of another table B, thereby establishing a link between them.

To provide referential integrity you can use these referential actions:

Cascade: If rows in table B are deleted, the matching foreign key columns in table A are deleted.

Set Null: If rows in table B are deleted, the matching foreign key columns in table A are set to null.

Set Default: If rows in table B are deleted, the matching foreign key columns in table A are set with the default value of the column.

Restrict: A value in table B cannot be deleted or updated while as it is referred to by a foreign key in table A.

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I need help solving this problem on Picoctf. The question is What happens if you have a small exponent? There is a twist though,

soldi70 [24.7K]

Explanation:

Explanation:

RSA encryption is performed by calculating C=M^e(mod n).

However, if n is much larger than e (as is the case here), and if the message is not too long (i.e. small M), then M^e(mod n) == M^e and therefore M can be found by calculating the e-th root of C.

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3 years ago

Given an input array of strings (characters) s, pick out the second column of data and convert it into a column vector of data.

hodyreva [135]

Answer:

Consider the following code.

Explanation:

save the following code in read_and_interp.m

function X = read_and_interp(s)

[m, n] = size(s);

X = zeros(m, 1);

for i = 1:m

if(str2num(s(i, 2:5)) == 9999)

% compute value based on previous and next entries in s array

% s(i, 2:5) retrieves columns 2-5 in ith row

X(i,1) = (str2num(s(i-1 ,2:5)) + str2num(s(i+1,2:5)))/2;

else

X(i,1) = str2num(s(i,2:5));

end

======================

Now you can use teh function as shown below

s = [ 'A' '0096' ; 'B' '0114' ; 'C' '9999' ; 'D' '0105' ; 'E' '0112' ];

read_and_interp(s)

output

ans =

96.000

114.000

109.500

105.000

112.000

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3 years ago

You are trying to determine why a packet of data is not being correctly sent over the internet. You determine that the problem i

spayn [35]

Answer is A it has a false ip so that is why an error is happening therefore the answer would be A.

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3 years ago

Read 2 more answers

What is the best Describe an integer data type

kolbaska11 [484]

Answer:

It is a data type that only holds whole numbers, a.k.a. integers.

what is the picture about?

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3 years ago

A(n) ________ event is an alert that is generated when the gossip traffic enables a platform to conclude that an attack is under

Allisa [31]

Answer:

B. DDI

Explanation:

A(n) DDI event is an alert that is produce or invoke when the gossip traffic allow a platform to conclude that an attack or potential attack is under way.

A device driver is a computer program that operates or controls a particular type of device that is attached to a computer system.

A driver provides or supply a software interface to hardware devices which enable the operating systems and other computer programs to access hardware functions without needing to know the exact details in respect of the hardware being used.

DDI means Device Driver Interface

A driver relate or communicate with the device via the computer bus or communications subsystem to which the hardware is connected. Whenever a calling program invokes a routine in the driver, the driver will subsequently transmit commands to the device.

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3 years ago