I've been trying to query data from a PostgreSQL DB via R. I've tried skinning the cat with a few different packages (RODBC, RJDBC, DBI, RPostgres
, etc), but I seem to keep getting driver errors. Oddly, I never have trouble using the same drivers/URL's and settings to connect to Postgres from SQLWorkbench/J.
I've tried using postgresql-9.2-1002.jdbc4.jar
and postgresql-9.3-1100.jdbc41.jar
, as well as the generic "PostgreSQL"
driver in R. The two jar files are the (i) the driver I use all the time with SQLWorkbench/J and (ii) the slightly newer version of that same driver, respectively. Yet, when I try to use it...
drv_custom <- JDBC(driverClass = "org.postgresql.Driver", classPath="/Users/xxxx/postgresql-9.3-1100.jdbc41.jar")
I get an error:
Error in .jfindClass(as.character(driverClass)[1]) : class not found
OK, so next I try it with the generic driver:
drv_generic <- dbDriver("PostgreSQL")
and strangely, it doesn't want me to enter a username:
>con <- dbConnect(drv=drv_generic, "jdbc:postgresql://xxx.xxxxx.com", port=xxxx, uid="xxxx", password="xxxx")
>Error in postgresqlNewConnection(drv, ...) : unused argument (uid = "xxxx")
so I try it without user/uid:
con <- dbConnect(drv_generic, "jdbc:postgresql://padb-01.jiwiredev.com:5439", password="paraccel")
and get an error....
Error in postgresqlNewConnection(drv, ...) :
RS-DBI driver: (could not connect jdbc:postgresql://padb-01.xxx.com:5439@local on dbname "jdbc:postgresql://xxxx.xxxx.com:5439")
Apparently the syntax is wrong?
Then I circle back to trying the "custom" driver (either one of the .jar files from earlier) but without the driverClass specified.
drv_custom1 <- JDBC( classPath="/Users/xxxx/postgresql-9.2-1002.jdbc4.jar")
con <- dbConnect(drv=drv_custom1, "jdbc:postgresql://xxx.xxx.com", port=5439, uid="paraccel", pwd="paraccel")
and get this error:
Error in .jcall(drv@jdrv, "Ljava/sql/Connection;", "connect", as.character(url)[1], :
RcallMethod: attempt to call a method of a NULL object.
I tried it again with a slight alteration to the syntax:
con <- dbConnect(drv=drv_custom1, url="jdbc:postgresql://xxxx.xxxx.com", port=xxxx, uid="xxxx", pwd="xxxxx",dsn="xxxx")
and got the same error. I tried a number of other variations/approaches as well. I think part of my confusion comes from the fact that the documentation is handled in a very piecemeal way between packages like DBI and those that build upon it like RJDBC, so that when I look at documentation such as ?dbConnect
many of the options I need to specify are not even mentioned, and I've been working based off of miscellaneous Google search results related to these packages/errors.
One thread I found suggested trying
.jaddClassPath( "xxxxx/postgresql-9.2-1002.jdbc4.jar" )
first, but that didn't seem to help.
I also tried using
x <- PostgreSQL(max.con = 16, fetch.default.rec = 500, force.reload = FALSE)
to no avail and I experimented with RODBC as the driver.
UPDATE:
I tried using an older version of the driver (jdbc3 instead of jdbc4), restarting R, and detaching all unnecessary packages.
I was able to load the driver
> drv_custom <- JDBC(driverClass = "org.postgresql.Driver", classPath="/xxxxx/xxxxx/postgresql-9.3-1100.jdbc3.jar")
but I still can't connect...
> con <- dbConnect(drv=drv_custom, "jdbc:postgresql://xxxxx.xxxxx.com", port=5439, uid="xxxxx", pwd="xxxxx")
Error in .verify.JDBC.result(jc, "Unable to connect JDBC to ", url) :
Unable to connect JDBC to jdbc:postgresql://xxxxx.xxxx.com
This works for me:
library(RJDBC)
drv <- JDBC("org.postgresql.Driver","C:/R/postgresql-9.4.1211.jar")
con <- dbConnect(drv, url="jdbc:postgresql://host:port/dbname", user="<user name>", password="<password>")
The trick was to include port
and dbname
in the url
. For some reason, jdbc:postgresql
does not seem to like reading those information from the dbConnect
parameters.
dbname
is, it is perhaps postgres
.port
is, it is perhaps 5432
.So a typical call would look like:
con <- dbConnect(drv, url="jdbc:postgresql://10.10.10.10:5432/postgres", user="<user name>", password="<password>")
You can get the jar
file from https://jdbc.postgresql.org/