This is the module for accesing Postgresql database from IDL. It was mostly written by Erin Sheldon. I have extracted it from sdssidl ( http://code.google.com/p/sdssidl/ ) and made the installation simpler. INSTALLATION: The pre-requisite is that you have to download the postgresql tarball from http://www.postgresql.org/ftp/source/ and put it in this directory (no need to extract it). You also should have idl in your path After that just run make This will create the directory called DLM which will have a dynamically loadable IDL module. You can put this directory anywhere and add the path to it to the environmental variable IDL_DLM_PATH, e.g. export IDL_DLM_PATH=some_path/DLM After that in any IDL session you should be able to use pgsql_query() function IDL> res=pgsql_query('select ra,dec from sdssdr7.phototag limit 10',connect_info='host=some_host user=some_user password=some_password dbname=some_dbname') % Loaded DLM: PGSQL_QUERY. IDL> print, res { 329.12152 44.397910}{ 329.14333 44.390562}{329.14613 44.392761}{ 329.14461 44.392961}{ 329.14460 44.392961}{ 329.14893 44.393050}{ 329.14863 44.393803}{ 329.14229 44.395501}{ 329.14278 44.396347}{ 329.15523 44.395887} IDL> help,res,/str ** Structure <2948e08>, 2 tags, length=16, data length=16, refs=1: RA DOUBLE 329.12152 DEC DOUBLE 44.397910 IF you don't want to type all the time the connection info, you should define the environmental variables: PGHOST PGDATABASE PGUSER PGPASSWORD export PGHOST=hostname_of_the_database_server export PGDATABASE=dbname export PGUSER=your_username export PGPASSWORD=your_password If you define these, you can easily query without additional arguments: Running the .idl_startup script... IDL> res=pgsql_query('select ra,dec from sdssdr7.phototag limit 10')