Rails, Postgres, environment variables, Ubuntu, no PL/R

[Ralph Shnelvar]

This may be more of a Postgres question than a Rails or Ruby question but ... since I want to do this in a Rails environment ...

I store my Postgres password in an environment variable whose name is a long randomly generated string in the appropriate format for an Ubuntu environment variable name..

Is it possible to get a list of environment variables from a (SELECT?) statement when executing an arbitrary SQL statement such as the two immediately below.

# Get a connection to a user's database.
# Once my question is answered, I'll want to ask questions about how the statmeent immediately below interacts with Rails'
#   connection pool.
conn = PGconn.connect("localhost", 5432,"","","my_database_development","MyUserName","MyObviousPassword")

exec_sql_stmt_OK =
"DROP TABLE IF EXISTS logs;
CREATE TABLE logs (
  client_ip inet,
  username text,
  ts timestamp,
  request text,
  status smallint,
  bytes int
);"

# Is there some way to break my security model?
# Note, I'm picking up the text of exec_sql_stmt_BAD_BAD_BAD from a form.  Hence the use of single quotes to prevent interpolation.
exec_sql_stmt_BAD_BAD_BAD =
'
Some statement that will break my security model by giving a list of environment variables;
;'

# This will execute just fine
ret_exec_sql = conn.exec( exec_sql_OK )

# I hope there is no SQL statement that will fetch a list of environment variables if PL/R is not installed.
ret_exec_sql = conn.exec( exec_sql_stmt_ BAD_BAD_BAD )

It is important to note that I have NOT installed R or PL/R.

Note: If PL/R is installed one can use the plr_environ() function to get a list of environment variables

Does anyone know a good (best?) forum to ask questions?  I see Reddit link but if you know of a better place, I'm all ears.