[R] Numerical print format and loading with RMySQL

Nathan Johnson njohnson at ebi.ac.uk
Tue Jun 13 16:57:02 CEST 2006


I'm new to R and have been resisting posting to the list thus far,  
but I think I've exhausted my work around options.

I'm having a few problems with RMySQL and/or it's underlying packages.

I'm doing a very simple vsn transformation on large datasets, using  
RMySQL to retrieve the data for a DB.

My first problem was that I could not get the RMySQL package to write  
back to my DB using the dbWriteTable method.

I constructed a data frame with columns corresponding to the table  
fields, and tried with and without a null column for the auto- 
increment internal id column.  I also tried renaming all the column  
names to match those of the table fields.  All of my attempts  
resulted in a long wait and "TRUE" being printed to the terminal,  
which I though was quite promising, however, on inspection of the DB,  
I found nothing had been written.  So my first question are:

Is it necessary to provide field names of the table, or will correct  
column order suffice?
For tables with an internal auto-increment DBID field, is it  
necessary to provide a null column of the correct length?

To get around this I decided to use the write.table function and then  
import via my controlling perl script.  This works fine apart from  
one problem, numbers >-100000 get printed as exponents, which then  
causes subsequent imports to miss these records. So my second and  
rather simple question is:

Is there a setting(options?) which will force full numerical printing?

Thanks in advance


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