[R] loading both RPostgreSQL and RSQLite leads to problems

[Martin Morgan]

On 08/22/2012 01:35 PM, Jon McAuliffe wrote:
> hello,
>
> if i load the RSQLite package in addition to the RPostgreSQL package,
> i get various errors when trying to use RPostgreSQL functions. here is
> an example transcript showing one such error:
>
>
> ==========================================================
> R version 2.15.0 (2012-03-30)
> [...]
>> packageVersion('RPostgreSQL')
> [1]  0.3.2
>> packageVersion('RSQLite')
> [1]  0.11.1
>> library(RPostgreSQL)
> Loading required package: DBI
>> dbDriver('PostgreSQL')
> <PostgreSQLDriver:(32540)>
>> library(RSQLite)
>> dbDriver('PostgreSQL')
> Error in function (classes, fdef, mtable)  :
>   unable to find an inherited method for function "show", for signature "PostgreSQLDriver"

Hi Jon --

It seems like this has been addressed in the devel version of R

 > library(RSQLite)
Loading required package: DBI
 > library(RPostgreSQL)
 > dbDriver("PostgreSQL")
An object of class "PostgreSQLDriver"
Slot "Id":
[1] 12355

 > sessionInfo()
R Under development (unstable) (2012-08-20 r60336)
Platform: x86_64-unknown-linux-gnu (64-bit)

locale:
  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
  [7] LC_PAPER=C                 LC_NAME=C
  [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] RPostgreSQL_0.3-2    RSQLite_0.11.1       DBI_0.2-5


> ==========================================================
>
>
> below is the output of showMethods('show') in two scenarios:
> (1) RPostgreSQL loaded, RSQLite not loaded;
> (2) RPostgreSQL loaded, RSQLite loaded (in that order).
> i'd be grateful for any help resolving or working around this issue.
> if possible, please include my email address in any reply.
>
> best
> jon mcauliffe
> jon at mcauliffe.com
>
>
>
> (1)
>> showMethods('show')
> Function: show (package methods)
> object="ANY"
> object="classGeneratorFunction"
> object="classRepresentation"
> object="dbObjectId"
> object="envRefClass"
> object="function"
>     (inherited from: object="ANY")
> object="genericFunction"
> object="genericFunctionWithTrace"
> object="MethodDefinition"
> object="MethodDefinitionWithTrace"
> object="MethodSelectionReport"
> object="MethodWithNext"
> object="MethodWithNextWithTrace"
> object="namedList"
> object="ObjectsWithPackage"
> object="oldClass"
> object="PostgreSQLDriver"
>     (inherited from: object="dbObjectId")
> object="refClassRepresentation"
> object="refMethodDef"
> object="refObjectGenerator"
> object="signature"
> object="sourceEnvironment"
> object="standardGeneric"
>     (inherited from: object="genericFunction")
> object="traceable"
>
>
> (2)
>> showMethods('show')
> Function: show (package methods)
> object="ANY"
> object="classGeneratorFunction"
> object="classRepresentation"
>   (2 methods defined for this signature, with different packages)
> object="envRefClass"
> object="genericFunction"
> object="genericFunctionWithTrace"
> object="MethodDefinition"
> object="MethodDefinitionWithTrace"
> object="MethodSelectionReport"
> object="MethodWithNext"
> object="MethodWithNextWithTrace"
> object="namedList"
> object="ObjectsWithPackage"
> object="oldClass"
> object="refClassRepresentation"
> object="refMethodDef"
> object="refObjectGenerator"
> object="signature"
> object="sourceEnvironment"
> object="traceable"
>
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