Is there any solution for drawing simple graphs in LaTeX like the following? I came across tikz but couldn't figure out how to do it. Are there also possibilities to extend such graphs without caring too much about node distances etc?

Is there any solution for drawing simple graphs in LaTeX like the following? I came across tikz but couldn't figure out how to do it. Are there also possibilities to extend such graphs without caring too much about node distances etc?

\tikzset{ myell/.style={ draw, ellipse } }
\begin{document}
\begin{tikzpicture}[node distance=1cm and 2cm] \node[myell] (sub) {Subject}; \node[myell,right=of sub] (obj) {Object}; \draw[->] (sub) -- node[above]{Predicate} (obj); \end{tikzpicture}
\end{document}`.
– Gonzalo Medina Jun 11 '14 at 18:49\documentclass{...}and ending with\end{document}. – Jun 11 '14 at 19:07