\begin{frame}
  \frametitle{Imperative vs. Declarative Languages}
    
  \begin{block}{}
    \hphantom{(Kowalski)} \hfill Algorithm = Logic + Control \hfill (Kowalski)
  \end{block}
  \smallskip

  \emph{Imperative} languages: 
  \begin{itemize}
    \item explicit control 
    \item implicit logic
  \end{itemize}
  \smallskip
  
  \emph{Declarative} languages:
  \begin{itemize}
    \item implicit control
    \item explicit logic
  \end{itemize} 
  
  \begin{exampleblock}{Examples of declarative languages}
    \begin{itemize}
      \item logic programming (e.g. Prolog),
      \item functional programming (e.g. Haskell),
      \item markup languages (e.g. HTML), \ldots
    \end{itemize}
  \end{exampleblock}
  \smallskip\pause
  
  Relational databases usually use SQL as query language \ldots
\end{frame}