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\begin{frame}
  \frametitle{Example}
  
  \booksexample  
  \medskip\pause
  
  \only<2>{
  \begin{itemize}
    \item The ISBN uniquely identifies a book. Thus
          \begin{talign}
            \sql{ISBN} \to \sql{TITLE}, \sql{PUBLISHER}
          \end{talign}
          Equivalently 
          \begin{itemize}
            \item $\sql{ISBN} \to \sql{TITLE}$, and
            \item $\sql{ISBN} \to \sql{PUBLISHER}$
          \end{itemize}
  \end{itemize}
  }
  \only<3>{
  \begin{itemize}
    \item A book may have many authors. Thus 
      \begin{talign}
        \sql{ISBN} \to \sql{AUTHOR}
      \end{talign}
      \text{\alert{does not hold!}}
  \end{itemize}
  }
  \only<4>{
  \begin{itemize}
    \item One author can write many books, thus 
      \begin{talign}
        \sql{AUTHOR} \to \sql{TITLE} \quad{\text{}}
      \end{talign}
      \alert{does not hold in general.}\\[1ex]
      
      Although it happens to hold in the above database state.
  \end{itemize}
  }
  \only<5>{
  \begin{itemize}
    \item 
      There may be books with the same title but different authors and different publishers.
      So 
      \begin{talign}
        \sql{TITLE}
      \end{talign}
      determines no other attributes.
  \end{itemize}
  }
  \only<6>{
  \begin{itemize}
    \item Every book has only one first (second, third, \dots)
      author. Thus\vspace{-1ex}
      \begin{talign}
        \sql{ISBN}, \sql{NO} \to \sql{AUTHOR}
      \end{talign}
  \end{itemize}
  }
  \only<7>{
  \begin{itemize}
    \item 
      At first glance, the author of any given book is also
      uniquely assigned a position in the authorship sequence.
      \begin{talign}
        \sql{ISBN}, \sql{AUTHOR} \to \sql{NO} \quad\text{\alert{? questionable}}
      \end{talign}
      However, violated by an author list like Smith \& Smith.
  \end{itemize}
  }
  \only<8>{
  \begin{itemize}
    \item What about the functional dependency
      \begin{talign}
      \sql{PUBLISHER}, \sql{TITLE}, \sql{NO} \to \sql{AUTHOR}\quad\text{\alert{? questionable}}
      \end{talign}
      Authorship sequence might change in a new edition of a book!
  \end{itemize}
  }
  \only<9>{
    \begin{goal}{}
      During database design, \emph{only unquestionable conditions should be used
      as functional dependencies}.
    \end{goal}
    \begin{itemize}
      \item Database normalization \emph{alters the table structure} depending 
        on the specified functional dependencies.\\
        \remark{Later hard to change: needs creation/deletion of tables!}
    \end{itemize}
  }
  \vspace{10cm}
\end{frame}