Using Ruby on Rails
with legacy Oracle databases
Raimonds Simanovskis

Ruby => Oracle
require 'oci8'
Ruby application OCI8.new('scott', 'tiger').exec(
'select * from emp') do |r|
puts r.join(',')
end
ruby-oci8
Oracle Instant
Oracle Database
Client
SQL*Net

JRuby => Oracle
require \"java\"
sql =
Ruby application JavaSQL::DriverManager.getConnec
tion(db, user, password)
statement = sql.createStatement
status = statement.execute
\"select * from parts;\"
JRuby rs = statement.getResultSet()
JDBC driver Oracle Database
SQL*Net

ActiveRecord
Oracle Enhanced
Adapter

Ruby on Rails 2.x
=> Oracle
gem install activerecord-oracle_enhanced-adapter
database.yml
development:
adapter: oracle_enhanced
database: XE
username: blogdemo
password: blogdemo
encoding: utf8

SQL bind variables
database.yml Employee.find(1)
development: ActiveRecord
adapter: oracle_enhanced SELECT * FROM employees
database: XE WHERE (employees.id = 1)
username: blogdemo
password: blogdemo Oracle optimizer
encoding: utf8 SELECT * FROM employees WHERE
cursor_sharing: similar (employees.id = :SYS_B_0)

Oracle Data Types
Ruby Rails Oracle
Fixnum :integer NUMBER
Float :float NUMBER
BigDecimal :decimal NUMBER, DECIMAL
Time :datetime DATE
Time :time DATE
Date :date DATE
String :string VARCHAR2
String :text CLOB
True/FalseClass :boolean NUMBER(1), CHAR(1)

Workarounds
ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.
emulate_dates_by_column_name = true
hire_date # Oracle DATE => Ruby Date
hire_time # Oracle DATE => Ruby Time
set_date_columns :started_on, :finished_on
set_datetime_columns :start_date_and_time, :end_date_and_time
ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.
emulate_booleans_from_strings = true
active_flag # Oracle CHAR(1) ‘Y’/’N’ => true/false
set_boolean_columns :some_boolean_column
ignore_table_columns :attribute1, :attribute2

Calling PL/SQL from Ruby
require \"oci8\"
conn = OCI8.new(\"hr\",\"hr\",\"xe\")
cursor = conn.parse <<-EOS
BEGIN
:return := test_uppercase(:p_string);
END;
EOS
cursor.bind_param(':p_string',\"xxx\",String)
cursor.bind_param(':return',nil,String,4000)
cursor.exec
puts cursor[':return']
cursor.close

ruby-plsql gem
gem install ruby-plsql
require \"ruby-plsql\"
plsql.connection = OCI8.new(\"hr\",\"hr\",\"xe\")
puts plsql.test_uppercase('xxx')

ruby-plsql gem
plsql.connection = OCI8.new(\"hr\",\"hr\",\"xe\")
plsql.test_uppercase('xxx') # => \"XXX\"
plsql.test_uppercase(:p_string => 'xxx') # => \"XXX\"
plsql.test_copy(\"abc\", nil, nil) # => { :p_to => \"abc\",
# :p_to_double => \"abcabc\" }
plsql.test_copy(:p_from => \"abc\", :p_to => nil, :p_to_double => nil)
# => { :p_to => \"abc\",
# :p_to_double => \"abcabc\" }
plsql.hr.test_uppercase('xxx') # => \"XXX\"
plsql.test_package.test_uppercase('xxx') # => 'XXX'
plsql.hr.test_package.test_uppercase('xxx') # => 'XXX'
plsql.logoff

class Employee < ActiveRecord::Base
set_create_method do
plsql.employees_pkg.create_employee(
:p_first_name => first_name,
:p_last_name => last_name,
:p_employee_id => nil
Custom
)[:p_employee_id]
end
set_update_method do
CUD plsql.employees_pkg.update_employee(
:p_employee_id => id,
:p_first_name => first_name,
methods )
end
:p_last_name => last_name
set_delete_method do
plsql.employees_pkg.delete_employee(
:p_employee_id => id
)
end
end

Other features
• composite_primary_keys support
• NLS_DATE_FORMAT independent
• TIMESTAMP columns support
• Faster schema dump

DEMO
see code at
http://github.com/rsim/legacy_oracle_sample

Ruby on Rails application
Controller classes
(incoming request HTTP request
processing)
Browser
HTML result
Model classes View templates
(business logic) (HTML, Javascript)
Ruby on SQL update data
selects through API SQL
Rails on
Oracle
Oracle E-Business Suite database
new schema for web application
custom tables
synonym for
for web
views
EBS
application
synonym for
packages
APPS schema XXX schema
custom views
for data read data XXX tables
access
update data
custom or standard
API packages

HTTPS
Application server
Apache
Typical
HTTP
HAproxy balancer
application HTTP HTTP HTTP
server
Mongrel Mongrel ... Mongrel
TCP TCP TCP
processes SQL SQL SQL
Memcached
Oracle DB

Thank You!
http://blog.rayapps.com
http://github.com/rsim