rails-plsql

Middleware between ActiveRecord and Oracle Database

Description

This gem is ActiveRecord extension for some Oracle Database specific features such as pipelined functions or PL/SQL procedures. It uses ruby-plsql and oracle enhanced adapter gems as dependencies for connection to Oracle and calling PL/SQL procedures and functions. It also adds basic logger to my fork of ruby-plsql gem.

Installation

Rails 3.2

Just put this line into your Gemfile

gem 'rails-plsql', '~> 0.1', github: 'flash-gordon/rails-plsql'

Gem tested with MRI 1.9.2, 1.9.3, 2.0.0 and JRuby 1.7.4. So if you use ruby-oci8 then add also

gem 'ruby-oci8', '~> 2.1.0'

And run

bundle install

to install all gems.

Other versions of Rails not tested.

Usage

Pipelined functions as tables in ActiveRecord models

Oracle pipelined functions could be used as data source instead of ordinary tables (or views).

If you have such PL/SQL function

CREATE OR REPLACE
PACKAGE users_pkg IS

  TYPE users_list IS TABLE OF USERS%ROWTYPE;

  FUNCTION find_users_by_name(
    p_name    USERS.NAME%TYPE)
  RETURN users_list
  PIPELINED;

END users_pkg;
/

CREATE OR REPLACE
PACKAGE BODY users_pkg IS

  FUNCTION find_users_by_name(
    p_name    USERS.NAME%TYPE)
  RETURN users_list
  PIPELINED
  IS
  BEGIN
    FOR l_user IN (
      SELECT *
      FROM   users
      WHERE  name = p_name)
    LOOP
      PIPE ROW(l_user);
    END LOOP;
  END FIND_USERS_BY_NAME;

END users_pkg;
/

So you can set this function in your model instead of table name

class User < ActiveRecord::Base
  include ActiveRecord::PLSQL::Pipelined

  self.pipelined_function = 'users_pkg.find_users_by_name'

  scope :alberts, where(p_name: 'Albert')
  scope :einsteins, where(surname: 'Einstein')
end

and use standard Rails scopes and finders

User.alberts
# [#<User id: #<BigDecimal:6fec77a4,'0.1E1',9(36)>, name: "Albert", surname: "Einstein">]
User.alberts.einsteins.first
# #<User id: #<BigDecimal:6fec77a4,'0.1E1',9(36)>, name: "Albert", surname: "Einstein">

User.all(conditions: {p_name: 'Max'})
# [#<User id: #<BigDecimal:6ee2c728,'0.3E1',9(36)>, name: "Max", surname: "Planck">]

Pipelined function arguments must be set via where condition (see p_name usage above). If not they will be set to NULL.

Oracle procedures and functions as methods of ActiveRecord objects

If you have some PL/SQL package related with AR model you could bind it to class.

CREATE OR REPLACE
PACKAGE users_pkg IS

  FUNCTION salute(
    p_name    IN VARCHAR2)
  RETURN VARCHAR2;

END users_pkg;
/

CREATE OR REPLACE
PACKAGE BODY users_pkg IS

  FUNCTION salute(
    p_name    IN VARCHAR2)
  RETURN VARCHAR2
  IS
  BEGIN
    RETURN 'Hello, ' || p_name || '!';
  END salute;

END users_pkg;
/

class User < ActiveRecord::Base
  include ActiveRecord::PLSQL::ProcedureMethods

  self.plsql_package = plsql.users_pkg
  procedure_method :salute
end

After that you can call procedure as method

einstein = User.find_by_name('Albert')
# Just pass arguments as array or hash
einstein.salute(p_name: einstein.name)  # 'Hello, Albert!'
einstein.salute([einstein.surname])     # 'Hello, Einstein!'

Support

Feel free to contact me at fg@flashgordon.ru or send a pull request.