\begin{frame}
  \frametitle{Weak Entity Sets}

  \weakentityexample
  \medskip
  
  \begin{alertblock}{}
    There can be multiple payments with equal \disc{payment-number}\hspace*{-1cm}
    \begin{itemize}
    \medskip
      \item the \disc{payment-number} is \emph{not a key}
    \medskip
    \pause
      \item payments must always be associated to precisely one loan
    \medskip
    \pause
      \item the \disc{payment-number} identifies a payment uniquely only
            in combination with the loan-number of the associated loan%
    \medskip
    \pause
    \end{itemize}
    In other words, the \emph{discriminator} \disc{payment-number} is unique among
    all payments for a certain loan.
  \end{alertblock}
  \vspace{10cm}
\end{frame}