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\begin{frame}
\frametitle{Cardinality Limits}

\begin{goal}{}
\emph{Cardinality limits} express the number of entities
to which another entity can be associated via a relationship set.
\end{goal}
\medskip
\pause

There are many notations. The most intuitive notation is:
\begin{block}{}
\begin{center}
\begin{scope}
\node[relationship] (R) {R};
\node (l) [left of=R,entity,minimum size=4mm] {A}; \draw (R) -- node[above,pos=.6] {$M_1\sldots M_2$} (l);
\node (r) [right of=R,entity,minimum size=4mm] {B}; \draw (R) -- node[above,pos=.6] {$N_1\sldots N_2$} (r);
\end{scope}
\end{tikzpicture}
\end{center}\vspace{-3mm}

\begin{itemize}
\item Every entity $a$ from $A$ is connected to \\
at least $N_1$, and at most $N_2$ entities in $B$.
\smallskip
\item Every entity $b$ from $B$ is connected to \\
at least $M_1$, and at most $M_2$ entities in $A$.
\end{itemize}
\end{block}
\pause
\begin{itemize}
\item $0\sldots 1$\;= zero or one
\item $1\sldots 1$\;= precisely one
\item $0\sldots *$\;= any number
\item $1\sldots *$\;= at least one
\end{itemize}
\end{frame}