[R-sig-DB] RMySQL problem - inherited dbConnect method missing for MySQL

[Prof Brian Ripley]

Where did you get RMySQL_0.5-7.zip from?  Was it built for R 2.4.0?

The symptoms are those of using S4-using packages which have not been 
reinstalled for R 2.4.0.  The current version is RMySQL_0.5-9.tar.gz on 
CRAN, and I suggest you compile that from the sources.

On Thu, 19 Oct 2006, Dan Rie wrote:

> I am hoping that you can help me resolve a problem I am having using RMySQL.
> I've searched the R help news archives, but RMySQL appears to be so trouble
> free that there are remarkably few problems reported there, and none that
> appear to be related to mine.

Yours is a recent phenomenon.

> I am trying to use RMySQL_0.5-7 on a Windows XP-Pro machine running
> R 2.4.0 and MySQL v5.0.26.
>
> I believe that MySQL is installed and working properly (I an able to use
> MySQL in Python through MySQLdb without any difficulty), but it's possible
> that I have some configuration issue causing the problem described below.
> The MySQL server is running on the same machine that is running R.
>
> I have been working from the windows binary installation package
> RMySQL_0.5-7.zip.  I have installed it from the R Packages menu using
> "Install package(s) from local zip files...".   I have tried various
> combinations of adding Path references pointing to the folder with
> libmysql.dll and libmysql.lib using references pointing to the MySQL
> distribution version of these files and/or pointing to the RMySQL version of
> the files (which are a bit older than those in C:\Program Files\MySQL\MySQL
> Server 5.0\lib\opt).  I have also tried copying the three dll files to
> ...\R-2.3.0\bin.
>
> The problem if first evident when I attempt to create a connection, but may
> actually start when I attempt to create the driver variable.
> Here is the R transcript after loading the RMySQL package:
>
> # initialize and create MySQL driver variable
>   > m<-dbDriver("MySQL")   #does not create output like example code
>   > m
>   An object of class "MySQLDriver"
>   Slot "Id":
>   [1] 3376
> # create a DBI connection variable - Error results
>   > con <- dbConnect(m,host="localhost", user="Dan", password="abcdef",
> dbname="test")
>   Error in function (classes, fdef, mtable)  :
>               unable to find an inherited method for function "dbConnect",
>               for signature "MySQLDriver"
> # summary of m indicates another failure to find MySQL specific DBI function
>   > summary(m)
>   Error in function (classes,  fdef, mtable)  :
>               unable to find an inherited method for function "dbGetInfo",
>               for the signature "MySQLDriver"
> # m in expired state, but perhaps that is natural for uninitialized driver
>   > mysqlDriverInfo(m)
>   Error in mysqlDriverInfo(m)  : expired MySQLDriver
>
> # some diagnostic checks:
>   > z<-.packages()
>   > z
>   [1] "RMySQL"    "DBI"         "methods"    "stats"    "graphics"
> "grDevices"
>   [7] "utils"            "datasets"   "base"
>
>   > objects(2)
>    [1] "dbApply"                                "dbBuildTableDefinition"
>    [3] "ErrorClass"                            "isIDCurrent"
>    [5] "MySQL"                                 "mysqlCloneConnection"
>    [7] "mysqlCloseConnection"        "CloseDriver"
>    [9] "mysqlCloseResult"                "mysqlConnectionInfo"
>  [11] "mysqlDataType"                    "mysqlDBApply"
>  [13] "mysqlDescribeConnection"  "mysqlDescribeDriver"
>  [15] "mysqlDescribeFields"            "mysqlDescribeResult"
>  [17] "mysqlDriverInfo"                   "mysqlExecStatement"
>  [19] "mysqlFetch"                            "mysqlImportFile"
>  [21] "mysqlInitDriver"                    "mysqlNewConnection"
>  [23] "mysqlQuickSQL"                   "mysqlReadTable"
>  [25] "mysqlResultInfo"                   "mysqlWriteTable"
>  [27] "safe.write"                              "usingR"
>
> I have uninstalled, then reinstalled the RMySQL package, but the error
> persists.  I'm kind of at a loss as to what to do to fix this problem or
> even where to look for clues.  It looks like perhaps the RMySQL.dll is not
> being found, but it is in the directory that the zip file indicated
> (c:\Program Files\R\R-2.4.0\library\RMySQL\libs), and at least for some
> tests, the Path string includes that directory.   I've tried copying the
> file RMySQL.dll to the ....\R-2.4.0\bin directory, but no joy there either.
>
> Any help or suggestions that you can provide will be greatly appreciated.
>
> Regards,
>
> Dan Rie
> Scituate, MA
>
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-- 
Brian D. Ripley,                  ripley using stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595