\begin{frame} \frametitle{Introduction} \begin{goal}{} There are different normal forms. The main ones are: \medskip\pause \begin{itemize} \item \emph{Third Normal Form (3NF)}: the standard relational normal form used in practice (and education). \medskip\pause \item \emph{Boyce-Codd Normal Form (BCNF)}: \begin{itemize} \item a bit more restrictive \item easier to define \item better for our intuition of good database design \end{itemize} \pause Roughly speaking, BNCF requires that \emph{all FDs are keys.} \end{itemize} \end{goal} \medskip \pause \begin{itemize} \item In rare circumstances, a relation might not have an equivalent BCNF form while preserving all its FDs.\\ \remark{The 3NF normal form always exists (and preserves the FDs).} \end{itemize} \end{frame}