8/296
\begin{frame}
  \frametitle{Introduction}

  \begin{itemize}
  \item 
    \emph{Functional Dependencies (FDs)} 
    \begin{itemize}
      \item are a \emph{generalization of keys}
      \item central part of \emph{relational database design theory}
    \end{itemize}
    \smallskip
    \pause
    
  \item This theory defines when a relation is in \emph{normal form}.\\
    \remark{(with respect to a given set of functional dependencies)}
    \smallskip
    \pause
    
  \item It is usually a sign of \emph{bad database design} 
    if a schema contains relations that \emph{violate the normal form}.\\
    %\remark{There are exceptions and trade-offs, however.}
    \smallskip
    \pause

  \item If a normal form is violated
    \begin{itemize}
      \item data is stored \emph{redundantly} and
      \item information about different concepts is \emph{intermixed}
    \end{itemize} 
    \pause
  
    \begin{exampleblock}{}
      \centerline{\ttfamily\footnotesize\centering
      \colorbox{rellight}{%
        \begin{tabular}[t]{|r|r|r|c|}
          \multicolumn{4}{c}{COURSES} \\ \hline
          \hd{\underline{CRN}} & \hd{TITLE} & \hd{INAME} & \hd{PHONE} \\
          22268 & Databases I            & Grust & 7111 \\
          42232 & Functional Programming & Grust & 7111 \\
          31822 & Graph Theory           & Klotz & 2418 \\
          \hline
        \end{tabular}%
      }}
    \smallskip\pause
    
    The phone number for each instructor is stored multiple times!
    \end{exampleblock}
  \end{itemize}
\end{frame}