a: Primary key ~
b: social secruity number
What: In fact, the social security number is a primary key. By definition a primary key uniquely identifies a record in a database. This idea was necessary before electronic databases so as to keep track of individuals and their personal information. There are many unique identifiers that most people should be familiar with: license plates, finger prints and retinal scans all convey uniqueness.
Where: Reference Link Has Evaporated
Date: Dec 16 2011 7:53 PM
# 1570 Critique Analogy