Describe primary and foreign keys. How do they differ? When and ...

[cartlidgeashley]

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.

[Ptupou85]

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]

TYSM

[xthemafja]

Excellent