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Author Question: Describe primary and foreign keys. How do they differ? When and how they are needed? What will be ... (Read 34 times)

cartlidgeashley

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on: Jul 7, 2018
Describe primary and foreign keys. How do they differ? When and how they are needed?
 
  What will be an ideal response?

Question 2

Telecommuting is facilitated by all of the following except:
 
  A) privacy laws.
  B) low costs for personal computing products.
  C) Internet connectivity.
  D) software to facilitate remote collaboration.


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Ptupou85

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Reply #1 on: Jul 7, 2018
Answer to Question 1

A primary key is an attribute or a set of attributes whose values uniquely identify a row. The relationship between entities in different tables is established through foreign keys. The foreign key is an attribute in one table, the value of which must match the value of a primary or an alternate key in another table. Unlike primary keys, foreign keys are not required and do not, necessarily, identify a row uniquely. Like primary keys, a foreign key can be composite, consisting of more than one attribute.

Answer to Question 2

A


cartlidgeashley

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Reply 2 on: Jul 7, 2018
Excellent

mammy1697

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Reply 3 on: Yesterday
Gracias!

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