[R-sig-DB] Implementation of RMySQL

[Jeffrey Horner]

I noticed that this package stores pointers to MySQL related data 
structures i R objects as an integer vector of up to length 3:

(from RMySQL/src/RS-DBI.h):
/* In R/S a dbObject is a foreign reference consisting of a vector
  * of 1, 2 or 3 integers.  In the C implementation we use these
  * R/S vectors as handles (we could have use pointers).
  */

Why were they not stored in the R object using the R External Pointer 
interface, described here:

http://www.stat.uiowa.edu/~luke/R/references/weakfinex.html

On a related note, the connection is not closed when assigning NULL to 
the connection object. This could be accomplished by using the 
Finalization Interface described in the above reference... Any reason 
this was not used?

Also, in light of a recent discussion on the R-devel mailing list(see 
S3/S4 classes performance comparison), does the S4 implemented DBI 
package hinder performance in any way for the RMySQL package?

-- 
Jeffrey Horner       Computer Systems Analyst         School of Medicine
615-322-8606         Department of Biostatistics   Vanderbilt University