P. P. P. Ewi ng Getty Getty Getty 1980 1960 1970 1975 2-9. THIRD NORMAL FORM It is not always possible to find a lossless join dependency preserving decomposition into Boyce Codd normal form. If we relax the conditions for normality a little, however, we can find a lossless join dependency preserving "third" normal form, which is almost as good. 44 Normal Form Design Theory The relaxation involves making a distinction between prime and nonprime attributes. A prime attribute is one that is in some key; a non-prime attribute is in no key.