\begin{frame}
  \frametitle{Introduction}
  
  \begin{goal}{}
    If a ``good'' ER schema is transformed into the relational model,
    the result will \emph{satisfy all normal forms} (4NF,
    BCNF, 3NF).
  \end{goal}

  A normal form violation detected in the generated
  relational schema indicates a \emph{flaw} in the input ER design.
  \\[2ex] 
  This needs to be corrected on the ER level.
  \smallskip
  \pause

  \begin{exampleblock}{FDs in the ER model}
    The ER equivalent of the very first example in this chapter:
    \smallskip
    
    \begin{minipage}{.32\textwidth}
      \scalebox{.9}{
      \begin{tikzpicture}[every edge/.style={link}]
        \node[entity] (customer) {Courses};
        \node[attribute] [above left of=customer,node distance=1.7cm,shift={(-5mm,-3mm)}] {\key{courseNr}} edge (customer);
        \node[attribute] [above of=customer,node distance=1.3cm] {title} edge (customer);
        \node[attribute] [left of=customer,node distance=2.1cm,yshift=-1mm] {phone} edge (customer);
        \node[attribute] [below left of=customer,node distance=1.5cm] {instructor} edge (customer);
      \end{tikzpicture}
      }  
    \end{minipage}
    \begin{minipage}{.67\textwidth}
    \begin{itemize}
    \pause
    \item
      The FD $\text{instructor} \to \text{phone}$ leads to a
      violation of BCNF in the resulting table for entity Courses.
    \pause
    \item 
      \alert{Also in the ER model, FDs between attributes of an entity set
      should be implied by a key constraint.}
    \end{itemize}
    \end{minipage}
  \end{exampleblock}
\end{frame}