\documentclass{article}
%\VignetteIndexEntry{Implementation Notes}
\usepackage{parskip}
\newcommand\I[1]{\rule{0pt}{#1}}
\pagestyle{empty}
\begin{document}

\title{Implementation Notes}
\author{Arni Magnusson}
\maketitle
\thispagestyle{empty}

The following overview gives an idea (but no promises) of which functions may
work for databases other than MS SQL Server.

\vspace{6ex}

{\it Browse database}\\[-2ex]

\begin{tabular}{lll}
  \hline
  Function       & Gets information from              & Works for    \I{2.2ex}\\
  \hline
  \tt dbOverview & {\tt sqlTables()}, {\tt sqlColumns()}
                   ~ & All RODBC databases\I{2.4ex}\\
  \tt dbStorage  & \verb|sys.allocation_units|,       & MS SQL Server\I{2.4ex}\\
                 & {\tt sys.indexes}, {\tt sys.partitions},                   \\
                 & {\tt sys.schemas}, {\tt sys.tables}                        \\
  \tt dbTime     & {\tt sys.tables}, {\tt sys.views}  & MS SQL Server\I{2.4ex}\\
  \hline
\end{tabular}

\vspace{6ex}

{\it Browse table}\\[-2ex]

\begin{tabular}{lll}
  \hline
  Function          & Gets information from & Works for          \I{2.2ex}\\
  \hline
  \tt tableDim      & {\tt tableNrow()},
                      {\tt tableNcol()}     & All RODBC databases\I{2.4ex}\\
  \tt tableHead     & {\tt sqlQuery()}      & All RODBC databases\I{2.4ex}\\
  \tt tableNcol     & {\tt sqlColumns()}    & All RODBC databases\I{2.4ex}\\
  \tt tableNrow     & {\tt sqlQuery()}      & All RODBC databases\I{2.4ex}\\
  \tt tableOverview & {\tt sqlColumns()},
                      {\tt tableNrow()}     & All RODBC databases\I{2.4ex}\\
  \hline
\end{tabular}

\vspace{6ex}

{\it Helper functions}\\[-2ex]

\begin{tabular}{lll}
  \hline
  Function       & Gets information from & Works for          \I{2.2ex}\\
  \hline
  \tt tableQuote & (self-contained)      & All RODBC databases\I{2.4ex}\\
  \hline
\end{tabular}

\end{document}