We need the following in place before we can proceed with the steps required for the recipe:

1. Install osm2pgsql. If you are using Windows, follow the instructions available at http://wiki.openstreetmap.org/wiki/Osm2pgsql. If you are on Linux, you can install it from the preceding website or from packages. For example, for Debian distributions, use the following:

      $ sudo apt-get install osm2pgsql

2. For more information about the installation of the osm2pgsql command for other Linux distributions, macOS X, and MS Windows, please refer to the osm2pgsql web page available at http://wiki.openstreetmap.org/wiki/Osm2pgsql.
3. It's most likely that you will need to compile osm2pgsql yourself as the one that is installed with your package manager could already be obsolete. In my Linux Mint 12 box, this was the case (it was osm2pgsql v0.75), so I have installed Version 0.80 by following the instructions on the osm2pgsql web page. You can check the installed version just by typing the following command:

      $ osm2pgsqlosm2pgsql SVN version 0.80.0 (32bit id space)

4. We will create a different database only for this recipe, as we will use this OSM database in other chapters. For this purpose, create a new database named rome and assign privileges to your user:

      postgres=# CREATE DATABASE rome OWNER me;
      postgres=# \connect rome;
      rome=# create extension postgis;

5. You will not create a different schema in this new database, though, as the osm2pgsql command can only import OSM data in the public schema at the time of writing.
6. Be sure that your PostgreSQL installation supports hstore (besides PostGIS). If not, download and install it; for example, in Debian-based Linux distributions, you will need to install the postgresql-contrib-9.6 package. Then, add hstore support to the rome database using the CREATE EXTENSION syntax:

      $ sudo apt-get update
      $ sudo apt-get install postgresql-contrib-9.6
      $ psql -U me -d romerome=# CREATE EXTENSION hstore;