\begin{frame} \frametitle{Important Aspects of ORM Toolkits} \begin{itemize} \item Mapping specification: \begin{itemize} \item map relational data onto objects \item can largely be derived automatically \end{itemize} \pause\medskip \item Query language (e.g. HQL): \begin{itemize} \item adds object-oriented features to SQL \item typically queries as strings (second class citizen) \end{itemize} \pause\medskip \item Persistence: \begin{itemize} \item transaction semantics \item languages offer start of transactions, commit, abort \end{itemize} \pause\medskip \item Fetch strategies \begin{itemize} \item danger of implementing queries in Java \error \item object caching \end{itemize} \end{itemize} \end{frame}