Installing RPostgresql on a Mac with OSX 10.7.2 - macos

Question

I'm trying to install rpostgresql on a mac. I want to be able to connect to a server using an IP address and read the data into a dataframe. I downloaded the package from CRAN, and ran the following line:
install.packages('/Users/celenius/Downloads/RPostgreSQL_0.2-1.tar.gz', type='source')
This started to compile the package but resulted with the following error message:
> install.packages('/Users/celenius/Downloads/RPostgreSQL_0.2-1.tar.gz', type='source')
Installing package(s) into ‘/Library/Frameworks/R.framework/Versions/2.14/Resources/library’
(as ‘lib’ is unspecified)
inferring 'repos = NULL' from the file name
* installing *source* package ‘RPostgreSQL’ ...
** package ‘RPostgreSQL’ successfully unpacked and MD5 sums checked
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking for pg_config... /usr/bin/pg_config
checking for "/usr/include/libpq-fe.h"... yes
configure: creating ./config.status
config.status: creating src/Makevars
** libs
*** arch - x86_64
gcc-4.2 -arch x86_64 -std=gnu99 -I/Library/Frameworks/R.framework/Resources/include -I/Library/Frameworks/R.framework/Resources/include/x86_64 -I/usr/include -I/usr/local/include -fPIC -g -O2 -c RS-DBI.c -o RS-DBI.o
make: gcc-4.2: No such file or directory
make: *** [RS-DBI.o] Error 1
ERROR: compilation failed for package ‘RPostgreSQL’
* removing ‘/Library/Frameworks/R.framework/Versions/2.14/Resources/library/RPostgreSQL’
Warning in install.packages :
installation of package ‘/Users/celenius/Downloads/RPostgreSQL_0.2-1.tar.gz’ had non-zero exit status
I've looked through advice on the rpostgresql webpage (1, 2) but a lot of the suggestions are more than a year old so I thought there might be more recent advice on how to install this package.

Answer 1

If you want to connect to a postgre db, you also can use RODBC. Just install an ODBC driver (Lion should already include that for postgres) and you are ready to go.
I do that for conecting to my local postgre / postgis server and it works just fine.

Answer 2

You need Xcode installed in order to compile. Go into the Mac app store and search for, then install Xcode. It's free.
you can tell whether you already have gcc by doing a quick which gcc-4.2. My guess is that you do not. After installing Xcode, you should get /usr/bin/gcc-4.2 in response.
****EDIT****
After the comments about how you installed Xcode and still don't have gcc-4.2, I did a little bit of reading and it looks like you need to do one of the options listed in this Stack Overflow question: Setting GCC 4.2 as the default compiler on Mac OS X Leopard
This makes me wonder where my gcc-4.2 came from. Probably some fortuitous accident when I first got my MBP.

Answer 3

Since postgresql is required to build the package from source, you will need to install it. The easiest way to do so, if you use homebrew, is to simply do the following in a Terminal:
## install postgresql
brew install postgresql
## install the R package
Rscript -e "install.packages('RPostgreSQL', type = 'source')"
## remove postgresql (optional)
brew remove postgresql