Installing database driver for Oracle (activerecord-oracle_enhanced-adapter) is not a simple process.

• First, you need to install Oracle Instant Client.
• Second, you have to install ruby wrapper around Instant Client (ruby-oci8 gem). On some platforms it requires compiling source code.

Only after that you can install oracle database driver.

Here we discuss how to do it for OSX 10 operating system.

Create separate group (e.g. "oracle") in Gemfile for oracle ruby-oci8 client wrapper. You have to keep this gem in separate group because it requires special steps to be done before database driver can be installed.

# Gemfile

group :oracle do
  gem "ruby-oci8", "2.1.7"
end

Install ruby gems for your project with bundler tool. You have to bypass oracle client wrapper installation:

bundle install --without=oracle

without parameter will exclude oracle bundler group from the execution.

Check that you don't have ruby-oci8 installed yet:

gem list

Download Oracle Instant Client packages and save them locally (e.g. in "downloads" folder). You can find installation packages on www.oracle.com web site (you have to be registered user though).

Create configuration file for the installation (.oracle_client_provision.json) in the root of your project. It will define where you have downloaded files and some other parameters:

{

  "node": {
    "domain": "127.0.0.1",
    "user": "ENV['USER']",
    "home": "ENV['HOME']",
    "port": "",
    "remote": false
  }

  "project": {
    "home": "#{node.home}/my_project_with_oracle_driver",
    "ruby_home": "ENV['MY_RUBY_HOME']"
  },

  "instant_client": {
    "src_dir": "#{project.home}/downloads",
    "dest_dir": "#{oracle.oracle_base}/instantclient_11_2",

    "basic_zip": "#{instant_client.src_dir}/instantclient-basic-macos.x64-#{oracle.oracle_version}.zip",
    "sdk_zip": "#{instant_client.src_dir}/instantclient-sdk-macos.x64-#{oracle.oracle_version}.zip",
    "sqlplus_zip": "#{instant_client.src_dir}/instantclient-sqlplus-macos.x64-#{oracle.oracle_version}.zip"
  },

  "oracle": {
    "oracle_base": "/usr/local/oracle",
    "oracle_version": "11.2.0.4.0",
    "ruby_oci_version": "2.1.7",
    "tns_admin_dir": "#{oracle.oracle_base}/network/admin"
  }

}

We are going to run ruby from project.ruby_home on behalf of the node.user and we will use specific versions of oracle client and ruby-oci8 gem. We also specify where to look for installation packages (instant_client.src_dir) and where to install Instant Client (instant_client.dest_dir). Also, as you can see, we are using macos as a platform and x64 as an architecture.

Library itself if written in ruby, but for launching its code you have to use rake or thor. Here I provide thor script as an example:

require 'thor'
require 'oracle_client_provision'

class OracleClient < Thor
  @installer = OracleClientProvision.new self, ".oracle_client_provision.json"

  class << self
    attr_reader :installer
  end

  desc "install", "Installs Oracle Instant Client"
  def install
    OracleClient.installer.install
  end

  desc "uninstall", "Uninstalls Oracle Instant Client"
  def uninstall
    OracleClient.installer.uninstall
  end

  desc "verify", "Verifies Oracle Instant Client connection"
  def verify
    username = "scott"
    password = "tiger"
    schema   = "ORCL"
    sql      = "SELECT * FROM emp where rownum <= 10"

    OracleClient.installer.verify do
      "require 'oci8'; OCI8.new('#{username}','#{password}','#{schema}').exec('#{sql}') do |r| puts r.join(','); end"
    end
  end

end

Run this thor command:

thor oracle_client:install

After execution all Instant Client packages (basic, sdk and sqlplus) will be installed at the right location (instant_client.dest_dir) on your computer.

Remove .bundle folder in order to include "oracle" group into bundle execution and then run bundler with "oracle" group:

rm -rf .bundle

bundle

If you have Oracle installed locally with scott/tiger/ORCL, you can test it now:

thor oracle_client:verify

If you have oracle installed somewhere on the network, you can add TNS names inside your tnsnames.ora file located inside /usr/local/oracle/network/admin folder. You can set up this location via tns_admin_dir property inside your configuration file.

tnsnames.ora file will have this section:

MY_ORCL=
  (DESCRIPTION=
    (ADDRESS=
      (PROTOCOL=TCP)
      (HOST=db.your_host.com)
      (PORT=1521)
  )
  (CONNECT_DATA=
      (SID=MY_ORCL)
    )
  )

where you define MY_ORCL schema on db.your_host.com running on port 1521.

In order to use oracle driver inside rails application, you have to include it into your Gemfile:

# Gemfile

group :oracle do
  ...
  gem 'activerecord-oracle_enhanced-adapter', '1.5.5'
end

bundle install --without=oracle

thor oracle_client:install

rm -rf .bundle

bundle

thor oracle_client:verify