\begin{frame}
  \frametitle{Multi-Valued Attributes}

  \begin{goal}{}
    \emph{Multi-valued attribute} $A$ of an entity set $E$ is represented
    by \mpause[1]{a \emph{separate table} with:
    \begin{itemize}
      \item columns for the primary key of $E$, and
      \item a column for the attribute value
    \end{itemize}
    Each single value of the multi-valued attributes gets its own row.%
    }
  \end{goal}

  \begin{center}
  \scalebox{.92}{
  \begin{tikzpicture}[every edge/.style={link}]
    \node[entity] (customer) {customer};
    \node[attribute] (id) [at=(customer),shift={(-1cm,1cm)}] {\key{id}} edge (customer);
    \node[attribute] (name) [at=(customer),shift={(1cm,1cm)}] {name} edge (customer);
    \node[multi attribute] (phone) [at=(customer),shift={(3.5cm,0cm)}] {phone-number} edge (customer);
  \end{tikzpicture}}
  \end{center}

  \mpause{  
  \begin{center}
  {\small\ttfamily
    \colorbox{rellight}{%
      \begin{tabular}[t]{|r|r|}
        \multicolumn{2}{c}{Customer}        \\ \hline
        \hd{\key{id}} & \hd{name} \\ \hline 
        1 & Smith  \\
        2 & Jones \\
        3 & Brown \\
        4 & Ford  \\
        \hline
      \end{tabular}%
    }~\quad~%
    \colorbox{rellight}{%
      \begin{tabular}[t]{|r|r|}
        \multicolumn{2}{c}{Phone-number}        \\ \hline
        \hd{\key{id}$\;\to\;$Customer} & \hd{\key{number}} \\ \hline 
        1 & 06-19348472  \\
        1 & 0346-928475 \\
        3 & 06-13783933  \\
        3 & 0238-187333  \\
        3 & 0192-937189  \\
        \hline
      \end{tabular}%
    }
    }
  \end{center}
  }
\end{frame}