[R] How to save a model in DB and retrieve It

[Greg Snow]

Look at the serialize function, it may accomplish what you want.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Daniele Amberti
> Sent: Friday, April 02, 2010 2:37 AM
> To: r-help at r-project.org; r-sig-db at stat.math.ethz.ch
> Subject: [R] How to save a model in DB and retrieve It
> 
> I'm wondering how to save an object (models like lm, loess, etc) in a
> DB to retrieve and use it afterwards, an example:
> 
> wind_ms <- abs(rnorm(24*30)*4+8)
> air_kgm3 <- rnorm(24*30, 0.1)*0.1 + 1.1
> wind_dg <- rnorm(24*30) * 360/7
> ms <- c(0:25)
> kw_mm92 <- c(0,0,0,20,94,205,391,645,979,1375,1795,2000,2040)
> kw_mm92 <- c(kw_mm92, rep(2050, length(ms)-length(kw_mm92)))
> modelspline <- splinefun(ms, kw_mm92)
> kw <- abs(modelspline(wind_ms) - (wind_dg)*2 + (air_kgm3 - 1.15)*300 +
> rnorm(length(wind_ms))*10)
> #plot(wind_ms, kw)
> windDat <- data.frame(kw, wind_ms, air_kgm3, wind_dg)
> windDat[windDat$wind_ms < 3, 'kw'] <- 0
> model <- loess(kw ~ wind_ms + air_kgm3 + wind_dg, data = windDat,
> enp.target = 10*5*3) #, span = 0.1)
> 
> modX <- serialize(model, connection = NULL, ascii = T)
> 
> Channel <- odbcConnect("someSysDSN; UID=aUid; PWD=aPwd")
> sqlQuery(Channel,
> paste(
> "INSERT INTO GRT.GeneratorsModels
>            ([cGeneratorID]
>            ,[tModel]
>    VALUES
>            (1,",
>            paste("'", gsub("'", "''", rawToChar(modX)), "'", sep = ''),
>            ")", sep = "") )
> # Up to this it is working correctly,
> # in DB I have the "modX" variable
> # Problem arise retrieving data and 64kb limit:
>   strQ <- "
>     SELECT  CONVERT(varchar(max), tModel) AS tModel
>     FROM    GRT.GeneratorsModels
>     WHERE   (cGeneratorID = 1)
>     "
> x <- sqlQuery(Channel, strQ, stringsAsFactors = F, believeNRows =
> FALSE)
> x <- sqlQuery(Channel, strQ, stringsAsFactors = F, believeNRows =
> FALSE) #read error
> 
> 
> 
> Above code is working for simplier models that have a shorter
> representation in variable "modX".
> Any advice on how to store and retieve this kind of objects?
> Thanks
> Daniele
> 
> 
> ORS Srl
> 
> Via Agostino Morando 1/3 12060 Roddi (Cn) - Italy
> Tel. +39 0173 620211
> Fax. +39 0173 620299 / +39 0173 433111
> Web Site www.ors.it
> 
> -----------------------------------------------------------------------
> -------------------------------------------------
> Qualsiasi utilizzo non autorizzato del presente messaggio e dei suoi
> allegati è vietato e potrebbe costituire reato.
> Se lei avesse ricevuto erroneamente questo messaggio, Le saremmo grati
> se provvedesse alla distruzione dello stesso
> e degli eventuali allegati.
> Opinioni, conclusioni o altre informazioni riportate nella e-mail, che
> non siano relative alle attività e/o
> alla missione aziendale di O.R.S. Srl si intendono non  attribuibili
> alla società stessa, né la impegnano in alcun modo.
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.