[R] Ordered factors and DBMS

[Timothy H. Keitt]

Doug's suggestions of joining two tables or defining a new type are a 
good ones, although you would have to do some manual manipulations in 
raw SQL. There is a general need to be able to split compound R types 
across more than one SQL column. It may be possible with RPgSQL if you 
redefind rpgsql.format.values.factor and friends, but I haven't tried 
this myself. It is something to think about as we develop a more general 
db interface.

Tim

F. Tusell wrote:

>Is there any way of preserving order of ordered factors when storing a
>table in PostgreSQL?
>
>I have been  using PostgreSQL and the RPgSQL package  to store a large
>table with answers such  as "Strong disagreement", "Strong agreement",
>"Mild disagreement".  "Mild agreement".  When reading the  table, such
>answers are  turned into  factors, apparently in  reverse alphabetical
>order.  If I  reorder them  using ordered(factor,  levels=the  order I
>want), everything  is fine for the  session, but saving  the table and
>re-reading it reverts to the original order.
>
>I have  a vague  feeling of having  seen this  asked, but I  could not
>locate any  references. I looked  also B.D. Ripley's  "Using Databases
>with R", but this problem is not discussed.
>
>
>ft.
>

-- 
Timothy H. Keitt
Department of Ecology and Evolution
State University of New York at Stony Brook
Stony Brook, New York 11794 USA
Phone: 631-632-1101, FAX: 631-632-7626
http://life.bio.sunysb.edu/ee/keitt/



-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._