\begin{frame}
  \frametitle{Relation Schema: Notation}
  
  How to \emph{communicate schemas from human to human}?\\
  SQL \sql{create table} statements are far from ideal.
  \begin{center}
    \begin{code}{.5\textwidth}{Relation schema in SQL}
    \small
    \BUseVerbatim{createtable}
    \end{code}
  \end{center}
  \pause
  
  \begin{goal}{}
    If the column data types are not important, we can write
    \begin{center}
      \headerExercises
    \end{center}
  
    Also widely in use: sketch of the table header
    \begin{center}
      \small\ttfamily
        \colorbox{rellight}{%
          \begin{tabular}[t]{|r|r|r|r|}
            \multicolumn{4}{c}{Exercises}        \\ \hline
            \hd{\underline{category}} & \hd{\underline{number}} & \hd{topic} & \hd{maxPoints}\\ \hline
          \end{tabular}%
        }
    \end{center}
  \end{goal}
\end{frame}