Tue May 27 10:18:49 EDT 2014

Normal forms


 - all columns contain atomic values

 - values of each attribute contain only a single value

 Meaning: don't aggregate what should be separate and don't duplicate.
 Solve these issues by introducing new tables.


 - no non-prime attribute is dependent on any proper subset of any
   candidate key of the table

 Meaning: keys should be minimal, i.e. non-redundant.


 - all the attributes in a table are dependent on the primary key and
   only the primary key.

 Meaning: every non-key is a proper function of the primary key.

[1] http://en.wikipedia.org/wiki/First_normal_form
[2] http://en.wikipedia.org/wiki/Second_normal_form
[3] http://en.wikipedia.org/wiki/Third_normal_form