[R] loading both RPostgreSQL and RSQLite leads to problems

[Jon McAuliffe]

hi martin,

i have installed 2.15.2 and tried your code example below, but
i still get the same error:


> library(RSQLite)
Loading required package: DBI
> library(RPostgreSQL)
> dbDriver('PostgreSQL')
Error in function (classes, fdef, mtable)  : 
  unable to find an inherited method for function  show  for signature  "PostgreSQLDriver" 


are you able run this successfully in 2.15.2?

thanks
jon.


On Aug 23, 2012, at 12:38 PM, Martin Morgan wrote:

> 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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>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>> 
> 
> 
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