On last day of Oracle OpenWorld I did my unconference presentation - Using Ruby on Rails with legacy Oracle databases.

As I did not know if anyone will come to listen to it I was glad that six people attended (including Kuassi Mensah from Oracle who is helping to promote Ruby support inside Oracle). And on the previous day I also managed to show parts of my presentation to Rich and Anthony from Oracle AppsLab team.

I published my slides on Slideshare:

And I published my demo project on GitHub:

Thanks to all Oracle people who recognize my work on Ruby and Oracle integration and I hope that our common activities will increase number of Ruby and Rails projects on Oracle :)

In the previous post I wrote that I didn’t quite like drag-and-drop development style in JDeveloper that I experienced during Oracle OpenWorld hands-on session.

Today I was in Oracle BI Answers & Dashboard hands-on session and during this session I was also drag-and-dropping to create reports, charts and business intelligence dashboards. But in this case I liked it as it seemed natural way how to create such reports.

The main difference why I liked it was that I got immediate feedback how the end report will look like - after each change I could immediately see and test real report with real data. And such immediate feedback is key prerequisite for interactive analytical reporting development.

In JDeveloper case I needed to compile and build everything and restart local application server after each change to see real results from any change - and it took at least 10 seconds for just sample “hello world” application. I assume that this lag will be even longer in larger real projects. Probably it is not so long time but when you compare it to 1 second feedback time then anything larger seems long.

I also visited Oracle demo grounds where I discussed my concerns regarding JDeveloper drag-and-drop development style. At the end we reached common understanding that JDeveloper and ADF framework is really good for former Oracle Forms developers who do not want to learn HTML, CSS and Javascript and auto-generated applications could be quite OK for internal enterprise applications. But if you want to build advanced web applications you still need to learn and be expert in these web technologies (HTML, CSS and Javascript).

Today was my first day at Oracle OpenWorld and here are my first impressions from the sessions I attended.

The first one was Building Web 2.0 Social Applications in Ruby on Rails with BEA AquaLogic Interaction by Chris Bucchere where he explained how they built social application for BEA conference participants. And it was interesting to see also some code examples from this application that he presented.

And then after that I participated in three Oracle Develop hands-on sessions about Oracle SOA suite and WebCenter. I signed up for these sessions because I thought that they will be more technical and code-intensive compared to other sessions.

As a result I spent three hours in Oracle JDeveloper but all I was doing was dragging-and-dropping and filling some pop-up dialog boxes. I did not write single line of Java code during these workshops. And as a result I had just vague idea why all the dragged components worked together.

Having experience of coding in Ruby and trying to create small and beautiful code this drag-and-drop development did not feel quite natural for me. And I am afraid that this drag-and-drop development approach will create bunch of developers who will not be able to create real code anymore.

The other consequences of this drag-and-drop style coding is that it is hard to version control the resulting generated code and it is also much harder to unit test such generated code. Probably this is the reason why I could not find any OpenWorld session about unit testing and test-driven development.

Am I missing some hidden beauty of drag-and-drop development? Or am I spoiled with beauty of Ruby?

I just returned from RailsConf Europe in Berlin and attended a lot of good Ruby and Rails related sessions.

I also tried to submit there my session proposal about using Rails with Oracle but as there were too many good proposals and as my topic was with too narrow topic then it was not accepted. Therefore I used opportunity to give 5 minutes presentation about Oracle enhanced adapter in RejectConf where anybody could present anything.

Here are my slides that I used in this presentation. And at least one participant was interested in this topics as he uses Rails and Oracle and did not know about my adapter.

My next public appearance is planned at Oracle OpenWorld unconference where I have recerved time slot on Thursday, September 25th at 10am. Please come there if you are attending Oracle OpenWorld and are interested in how to use Ruby on Rails with your legacy Oracle databases.

Short information about latest enhancements in ActiveRecord Oracle enhanced adapter:

• Oracle enhanced adapter is now compatible with composite_primary_keys gem which is quite useful if you are working with legacy databases.
• Adapter now is also working correctly with Rails 2.1 partial_updates enabled. Previously I mentioned that you needed to disable partial_updates when using CLOB/BLOB columns. Now the issue is found and fixed and partial_updates are working with CLOB/BLOB columns.
• Support for other date and time formats when assigning string to :date or :datetime column. For example, if you would like to assign strings with format dd.mm.yyyy to date and datetime columns then add the following configuration options:

  ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.string_to_date_format = "%d.%m.%Y"
  ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.string_to_time_format = "%d.%m.%Y %H:%M:%S"
  

To get the new release of Oracle enhanced adapter do as always:

sudo gem install activerecord-oracle_enhanced-adapter

Warning: this post will be unrelatead to Ruby :)

For many years our company is using tool for Oracle E-Business Suite setup management that we initially built for our own purposes but now also we are offering to other Oracle partners and customers.

As I was bored to do demonstrations of it over and over again I finally decided to create a screencast of this tool (it’s 22 MB large). And I think that my first experiment in screencasting is not too bad :)

Previously screencasting was quite hard stuff as there was not so many good tools for that. In this case I used ScreenFlow tool which was released this year (and is available just on Mac OS X Leopard) and I have to say that it is much more better and easier compared to any other tools that I have seen earlier. So I am strongly recommending it to others who are interested in screencasting.

In some Ruby on Rails projects I am putting ActiveRecord interface on top of existing legacy databases. It is quite easy to specify legacy table names and primary keys in ActiveRecord models so that ActiveRecord would generate correct SQL SELECT statements to read data from legacy databases.

But it is more difficult to insert, update and delete in legacy databases using ActiveRecord. When using Oracle legacy databases then quite often they have exposed PL/SQL APIs for writing to tables and you are typically not allowed to directly modify tables with INSERT, UPDATE and DELETE statements.

Therefore I created support for custom create, update and delete methods in the version 1.1.3 of ActiveRecord Oracle enhanced adapter which uses also my ruby-plsql gem.

Let’s look at the following example. Assume that we have the following table:

      CREATE TABLE test_employees (
        employee_id   NUMBER(6,0),
        first_name    VARCHAR2(20),
        last_name     VARCHAR2(25),
        hire_date     DATE,
        salary        NUMBER(8,2),
        version       NUMBER(15,0),
        create_time   DATE,
        update_time   DATE
      )

And we have the following PL/SQL API package that should be used to write to this table:

      CREATE OR REPLACE PACKAGE test_employees_pkg IS
        PROCEDURE create_employee(
            p_first_name    VARCHAR2,
            p_last_name     VARCHAR2,
            p_hire_date     DATE,
            p_salary        NUMBER,
            p_employee_id   OUT NUMBER);
        PROCEDURE update_employee(
            p_employee_id   NUMBER,
            p_first_name    VARCHAR2,
            p_last_name     VARCHAR2,
            p_hire_date     DATE,
            p_salary        NUMBER);
        PROCEDURE delete_employee(
            p_employee_id   NUMBER);
      END;

Then we define ActiveRecord model in the following way:

    class TestEmployee < ActiveRecord::Base
      set_primary_key :employee_id
      # should return ID of new record
      set_create_method do
        plsql.test_employees_pkg.create_employee(
          :p_first_name => first_name,
          :p_last_name => last_name,
          :p_hire_date => hire_date,
          :p_salary => salary,
          :p_employee_id => nil
        )[:p_employee_id]
      end
      # return value is ignored
      set_update_method do
        plsql.test_employees_pkg.update_employee(
          :p_employee_id => id,
          :p_first_name => first_name,
          :p_last_name => last_name,
          :p_hire_date => hire_date,
          :p_salary => salary
        )
      end
      # return value is ignored
      set_delete_method do
        plsql.test_employees_pkg.delete_employee(
          :p_employee_id => id
        )
      end
    end

And as a result we can use this model in the same way as other ActiveRecord models:

    @employee = TestEmployee.create(
      :first_name => "First",
      :last_name => "Last",
      :hire_date => Date.today
    )
    @employee.reload
    @employee.first_name = "Second"
    @employee.save!
    @employee.destroy

And all writing to the database will be done using defined API procedures.

Currently this functionality is embedded into Oracle enhanced adapter but if somebody needs it also for other databases this functionality could easily be extraced from the adapter.

To get the new release of Oracle enhanced adapter just do:

sudo gem install activerecord-oracle_enhanced-adapter

Source code of Oracle enhanced adapter is located at GitHub and you can submit bug reports and enhancement requests in Lighthouse.

If you still have not voted for my session proposal “Using Ruby on Rails with Oracle E-Business Suite” then please do so :) Voting deadline is near - July 13th.

In any case I am going to be at Oracle OpenWorld conference in San Francisco in September. So if some of my blog readers will also be there and would like to have some chat with me about Oracle and Ruby then please let me know.

I just released new version of ActiveRecord Oracle enhanced adapter which includes several new enhancements which could be useful if you use ActiveRecord with legacy Oracle databases:

• Added ignore_table_columns option for class definitions

You can specify which table (or view) columns should be ignored by ActiveRecord - these could be either columns which you do not need in Rails application or which have currently unsupported data types. For example:

    class Employee < ActiveRecord::Base
      ignore_table_columns  :phone_number, :hire_date
    end

• Added support for TIMESTAMP columns

You can create tables with :timestamp data type which will create TIMESTAMP columns and you can access values from TIMESTAMP columns. Unfortunately due to current ruby-oci8 limitations when you will retrieve TIMESTAMP values it will be without fractional seconds (but if you pass Time value with fractional seconds then it will be stored in database).

• NLS_DATE_FORMAT and NLS_TIMESTAMP_FORMAT independent DATE and TIMESTAMP columns support

By default Oracle adapter (and enhanced adapter as well) changes NLS_DATE_FORMAT and NLS_TIMESTAMP_FORMAT to ‘DD-MON-YYYY HH24:MI:SS’. But if you are working with some legacy database which requires different NLS date settings then now you can change these settings to different ones. You can put in some initialization file some other NLS settings, e.g.:

ActiveRecord::Base.connection.execute %q{alter session set nls_date_format = 'DD-MON-YYYY HH24:MI:SS'}
ActiveRecord::Base.connection.execute %q{alter session set nls_timestamp_format = 'DD-MON-YYYY HH24:MI:SS'}

and ActiveRecord will continue to work correctly with date values.

Also one Rails 2.1 related issue was solved. Previously Oracle enhanced adapter always added after_save callback to ActiveRecord session store which stores BLOB data in the database (as in Rails 2.0 there was issue that this callback was not added). Now in Rails 2.1 this callback is added by ActiveRecord therefore Oracle enhanced adapter checks if this callback is already added or not. So now this should work correctly both in Rails 2.0 and Rails 2.1.

Also I have noticed that in some Rails 2.1 applications Oracle adapter is failing on ActiveRecord session store updates when partial updates are enabled. If you also have such issue then put this into your initialization file which will work as workaround until I will find what is causing this problem:

CGI::Session::ActiveRecordStore::Session.partial_updates = false

To get the new release just do:

sudo gem install activerecord-oracle_enhanced-adapter

Source code of Oracle enhanced adapter is located at GitHub. And you can submit bug reports and enhancement requests in Lighthouse. There you can see also some identified enhancements - please add comments to them if you also would like to have them. Then it will be easier for me to select what to include in next version of adapter.

Some time ago I created ruby-plsql gem which provides simple Ruby API for Oracle PL/SQL stored procedures.

Initially this gem supported just MRI with ruby-oci8 library which provides connectivity to Oracle database as this was my main development and production environment for Ruby & Oracle applications. But as JRuby is fast growing alternative Ruby deployment platform and as it can be integrated into Oracle Fusion middleware platform (e.g. Oracle Mix is running on JRuby on Oracle Fusion middleware) then I planned to support JRuby as well.

I started to work on JRuby support during RailsConf JRuby hackfest and initially this did not seem very hard task for me. But as I did not know JDBC very well it took me much more time than initially planned. And unfortunately JDBC is also much less powerful compared to ruby-oci8 library for construction of dynamic PL/SQL calls. In addition I needed to strugle with Ruby and JDBC data type mappings which differs from Ruby and ruby-oci8 data type mappings.

But finally I have completed JRuby support and released ruby-plsql gem version 0.2.0. And good news are that from usage perspective ruby-plsql behaves identically on MRI and JRuby - at least my RSpec tests are telling so.

To install this gem on JRuby execute

sudo jruby -S gem install ruby-plsql

or

sudo jgem install ruby-plsql

depending on how you have installed JRuby on your computer.

Source code of ruby-plsql is located on GitHub where you can find usage examples in RSpec tests.