\begin{frame} \frametitle{Boyce-Codd Normal Form: Examples} \begin{exampleblock}{} Each course meets once per week in a dedicated room: \begin{center} $\sql{Class(courseNr, title, weekday, time, room)}$ \end{center} \pause The relation thus satisfies the following FDs (plus implied ones):\pause \begin{center} $ \begin{array}{rcl} \sql{courseNr} & \to & \sql{title}, \sql{weekday}, \sql{time}, \sql{room} \\ \sql{weekday}, \sql{time}, \sql{room} & \to & \sql{courseNr}\pause% \end{array} $ \end{center} The minimal keys of \sql{Class} are \begin{itemize} \pause \item $\{\;\sql{courseNr}\;\}$ \pause \item $\{\;\sql{weekday}, \sql{time}, \sql{room} \;\}$ \end{itemize} \pause Is the relation in BCNF? \pause \begin{itemize} \item both FDs are implied by keys \\ \remark{(their left-hand sides even coincide with the keys)} \end{itemize} \pause Thus \sql{Class} \emph{is in BCNF.} \end{exampleblock} \end{frame}