Example:Tables are relations

From CS2800 wiki

For example, we could think of a table of blood donors containing names, birth dates, and social security numbers as a relation on the set Name of names, the set Date of dates, and the set SSN of social security numbers. We would represent this table:

Name Birthdate Social
Alice 01/01/2011 111-11-1111
Bob 02/02/1922 222-22-2222

As the relation [math]R := \{\href{/cs2800/wiki/index.php/Pair}{(Alice, 01/01/2011, 111-11-1111)}, \href{/cs2800/wiki/index.php/Pair}{(Bob, 02/02/1922, 222-22-2222)}\} [/math].

Thinking of tables as relations is central to the design of certain kinds of databases (so-called relational databases). Operations like "filter out the millenials", "hide the social security number", and "add a hair color column by looking up the name in a second table" are all functions whose domains and codomains are sets of relations.