[R] export from R to MySQL

[David James]

Prof Brian Ripley wrote:
> On Mon, 12 Dec 2005, Sean Davis wrote:
> 
> >
> >
> >
> > On 12/12/05 9:21 AM, "bogdan romocea" <br44114 at gmail.com> wrote:
> >
> >>> Sean Davis wrote:
> >>> but you will have to create the table by hand
> >>
> >> There's no need for manual steps. To take advantage of MySQL's
> >> extremely fast 'load data infile' you could dump the data in CSV
> >> format, write a script for mysql (the command line tool), for example
> >>
> >> q <- function(table,infile)
> >> {
> >> query <- paste("
> >> create table ",table," (col1 float, col2 float);
> >
> > This is creating the table by hand, as opposed to using dbWriteTable.  If
> > your data.frame contains 67 columns, using dbWriteTable saves quite a bit of
> > typing....
> 
> The RODBC equivalent creates the table for you, then fast imports the 
> file.  Might be worthwhile contribution to RMySQL for someone.
> 

That's what RMySQL's dbWriteTable() does.  The original posting
mentioned problems associated with speed of data.frame and
dbWriteTable, which seems plausible (but I haven't quantified it
myself) given the fact that dbWriteTable outputs a data.frame to an
intermediate file via write.table and then uses the LOAD DATA for
fast loading that intermediate file.

> Just be careful with client-server systems to have the file in the right 
> place (if indeed you are allowed to have files on the server).
> 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> 
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--
David