\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}