emmanuel.charpentier at sap.ap-hop-paris.fr
Wed Nov 15 18:23:06 CET 2000
I saw in the R-digest a thread about RODBC.
1) I think that this package is *extremely* valuable : it fulfills a need
quite important in the case of iterative (e. g. periodic) analyses. No need to
periodically return to your data and re-dumping them ...
2) The current version has a serious bug if your datasets has missing numeric
values. M. Lapsley, the original author, is aware of it, but has had no time
yet to look at it ...
I looked into the source to no avail. I'll have to dive in ODBC library
mysteries (which are pure Swahili to me ...), and did not yet had time for
In interim, you can uncomment the old (much less efficient) of the odbcQuery
routine, which does *not* exhibit this bug. Data are correct, speed seriously
3) If you happen to use PostgreSQL, the RPgSql package (also on CRAN) is much
more interesting : it allows direct access to PostgreSQL classes (tables) as R
objects, ensuring that any R access is done to up-to-date data.
Of course, OTOH, if you happen to trash your R data-access-objects, your
original data are gone for good. Caveat emptor ...
4) IMNSHO, the future lies somewhere in the (hypothetical) fusion of these two
package : direct access to ODBC objects would be perfect (and might seriously
alleviate problems due to the R static memory allocation model, which is an
Hope this helps,
Emmanuel Charpentier Tel : +33-01 40 27 35 98
Secrétariat scientifique du CEDIT Fax : +33-01 40 27 55 65
Direction de la Politique Médicale // Assistance Publique - Hôpitaux de Paris
3, Avenue Victoria // F-75004 Paris /// France
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