RFC: large database interface
Mon, 20 Apr 1998 12:44:00 +1200 (NZST)
Egon Schmid writes:
> Thomas Lumley wrote:
> > I have been playing with a large database interface for R, and have
> > written one complete but useless demonstration and one incomplete but
> > potentially useful example (with memory mapping of a fixed-format ASCII
> > file). The idea is to make the file appear like a matrix or data frame but
> > not have to read it into the R heap.
> > A description and code can be found at
> > http://www.biostat.washington.edu/~thomas/Rdb.html
> > Rdb.nw (noweb literate program)
> > Rdb.c
> > Rdb.R
> > Comments?
This looks very interesting. It would be nice if the such an
interface were written in a way that could be customized to a variety
of applications. Being able to read spreadsheets is one thing which
comes to mind. It might be nice (for example) to have a rather
complex initialization procedure which inspects the dataset thoroughly
and determines things like variable types (if the database does not
contain this information).
Egon Schmid writes:
> Well, there is a web interface through the Apache module PHP Hypertext
> Preprocessor. At http://www.php.net/ there are plenty more database
> Personaly I think it would a great idea to interface large datasets with
> "Why not use an existing database management system for storing
> array-oriented data? Relational database software is not suitable for
> the kinds of data access supported by the netCDF interface.
Hmm. Over the past week I have been looking at NetCDF because GMT
(The Generic Mapping Tools)
use NetCDF to store their maps.
[ The maps are rather better than the Becker and Wilks ones because
they are based on the World Vector Shoreline as well as the CIA WDB
that B&W use. They also have the maps prepared pretty well for
plotting. The only place where B&W are better is in the naming
of places ... ]
I wasn't thinking about pulling the data from these maps into R, but
rather just rendering them on a graphics device so that they could
then be added to.
I suspect that when I've done that I'll probably know enough to create
an R/NetCDF link, perhaps using a framework of the type Thomas
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