[R] Problem connecting to database via RPostgreSQL/RS-DBI: "could not connect" error

[Paul Gilbert]

A post with subject "Basic R to SQL considerations" has been put on 
R-sig-DB to address some of the basic questions here. The R-sig-DB 
thread is not specific to  RPostgreSQL.

> I have learned enough since this posting to be aware that my question was
> based on assumptions so false to fact that they verge on the nonsensical,
> but not enough to reframe it more sensibly. So I am just going to say what I
> believed then and what I believe now, and perhaps you can head off the more
> extreme excursions from reality in my current beliefs.
>
> Because I knew that libpq depended on the version of PostgreSQL that was
> installed, and that it used to be the case that you could not just install
> the package, but it is now possible because of the addition of libpq, I
> concluded that libpq contained an installer for PostgreSQL. I now think that
> this is false, and that libpq is some sort of tailored interface that varies
> with the OS and the PostgreSQL version. Tailored where and by what, I still
> don't know, but maybe I do not need to know.
>
> Since I thought I had to use the version of PostgreSQL installed by libpq, I
> did not try to independently install PostgreSQL. Now I think that PostgreSQL
> has to be installed and working before you start to install RPostgreSQL, in
> order, among other things, to get the right libpq contents or settings.
>
> I spent most of a day trying to figure out how to do what I was thinking of
> as a "strictly local installation" of PostgreSQL, meaning one that did not
> connect to the internet via a port and TCP/IP. I now believe that there is
> no such thing, at least on a Windows machine, or that doing so would be
> complex and difficult, compared to a connection via a "machine-internal"
> TCP/IP connection -- something I did not know existed until the day before
> yesterday.
>
> For the last few days I have been trying, so far unsuccessfully, to install
> PostgreSQL from the (misnamed) "one click" installer from  enterprisedb.com.
> I have figured out that the installation and error logs are written to
> stderr, and where my OS puts it. I've gone through the 40+ pages of log.
> Although the log contains more than 2 dozen warnings and errors, I now
> believe that all of the ones that matter derive in some way from this one:
> "Executing batch file 'rad3BBD8.bat'...
> 'icacls' is not recognized as an internal or external command, operable
> program or batch file."
>
> . . . and that this means I am having some sort of problem with the Windows
> XP/NT access control/permissions system. Unfortunately I know nothing
> whatsoever about the Windows permission system. Learning about it is the
> next thing on my list.
>
> I am really quite good at framing feasible research agendas to address
> important policy questions on a shoestring. I'm good with regression, with
> displaying complicated argument in sensible graphics. I am new to using
> databases on my own behalf (rather than having someone to do it for me), but
> I am finding the query side of databases elegant and intuitive. But I am not
> a competent IT/sysadmin/tech support person, and I am not going to be one
> soon, or maybe ever. So I find it somewhat disheartening that I am spending
> so much time being just that.
>
> Still, I am very grateful for the help and support of this list and the
> various Stack Exchange lists, which have made possible such learning as I
> have been able to accomplish.  Like the glaciers, my progress is slow but
> inexorable. Or so I like to believe.
>
> Warmest regards, andrewH
>