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A ___domain which contains relations is called a [[finitary relation|nonsimple ___domain]], while a ___domain which does not contain relations is called a simple ___domain. Normalization to 1NF is thus a process of eliminating nonsimple domains from all relations.
 
E. F. Codd uses the terms ''atomic'' and ''nondecomposable'' for elements of simple domains<ref>Codd, E.F (1970). "A Relational Model of Data for Large Shared Data Banks". Communications of the ACM. Classics. 13 (6): 377–87. p. 380</ref>. Thus an atomic value is any value which is not a relation. Such values vannotcannot be decomposed using just [[relational algebra]] operators like selection or projection.
 
== Rationale ==