June 21, 2010

Oracle enhanced adapter 1.3.0 is Rails 3 compatible

Filed under: oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 4:02 pm

Rails 3 is in final finishing stage (currently in beta4) and therefore I released new Oracle enhanced adapter version 1.3.0 which I was working on during last months.

Rails 3 compatibility

The major enhancement is that Oracle enhanced adapter is now compatible with Rails 3. To achieve that I also developed Oracle SQL compiler for Arel gem which is used now by ActiveRecord to generate SQL statements. When using Oracle enhanced adapter with Rails 3 you will notice several major changes:

  • Table and column names are always quoted and in uppercase to avoid the need for checking Oracle reserved words.
    E.g. now Post.all will generate query
  • Better support for limit and offset options (when possible just ROWNUM condition in WHERE clause is used without using subqueries).
    E.g. Post.first (or Post.limit(1)) will generate query
    but Post.limit(1).offset(1) will generate
    select * from (select raw_sql_.*, rownum raw_rnum_ from (SELECT “EMPLOYEES”.* FROM “EMPLOYEES”) raw_sql_ where rownum <= 2) where raw_rnum_ > 1

When using Oracle enhanced adapter with current version of Rails 3 and Arel it is necessary to turn on table and column caching option in all environments as otherwise Arel gem will cause very many SQL queries on data dictionary tables on each request. To achieve that you need to include in some initializer file:

ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.cache_columns = true

I have published simple Rails 3 demo application using Rails 3 and Oracle enhanced adapter. You can take a look at Gemfile and Oracle initializer file to see examples how to configure Oracle enhanced adapter with Rails 3.

Rails 2.3 compatibility

Oracle enhanced adapter version 1.3.0 is still compatible with Rails 2.3 (I am testing it against Rails 2.3.5 and 2.3.8) and it is recommended to upgrade if you are on Rails 2.3 and plan to upgrade to Rails 3.0 later. But if you are still on Rails 2.2 or earlier then there might be issues with Oracle enhanced adapter 1.3.0 as I am using some Rails methods which appeared just in Rails 2.3 – so in this case it might be safer to stay on previous Oracle enhanced adapter version 1.2.4 until you upgrade to latest Rails version.

Oracle CONTEXT index support

Every edition of Oracle database includes Oracle Text option for free which provides different full text indexing capabilities. Therefore in Oracle database case you don’t need external full text indexing and searching engines which can simplify your application deployment architecture.

The most commonly used index type is CONTEXT index which can be used for efficient full text search. Most of CONTEXT index creation examples show how to create simple full text index on one table and one column. But if you want to create more complex full text indexes on multiple columns or even on multiple tables and columns then you need to write your custom procedures and custom index refreshing logic.

Therefore to make creation of more complex full text indexes easier I have created additional add_context_index and remove_context_index methods that can be used in migrations and which creates additional stored procedures and triggers when needed in standardized way.

This is how you can create simple single column index:

add_context_index :posts, :title

And you can perform search using this index with

Post.contains(:title, 'word')

This is how you create index on several columns (which will generate additional stored procedure for providing XML document with specified columns to indexer):

add_context_index :posts, [:title, :body]

And you can search either in all columns or specify in which column you want to search (as first argument you need to specify first column name as this is the column which is referenced during index creation):

Post.contains(:title, 'word')
Post.contains(:title, 'word within title')
Post.contains(:title, 'word within body')

See Oracle Text documentation for syntax that you can use in CONTAINS function in SELECT WHERE clause.

You can also specify some dummy main column name when creating multiple column index as well as specify to update index automatically after each commit (as otherwise you need to synchronize index manually or schedule periodic update):

add_context_index :posts, [:title, :body], :index_column =&gt; :all_text,
  :sync =&gt; 'ON COMMIT'
Post.contains(:all_text, 'word')

Or you can specify that index should be updated when specified columns are updated (e.g. in ActiveRecord you can specify to trigger index update when created_at or updated_at columns are updated). Otherwise index is updated only when main index column is updated.

add_context_index :posts, [:title, :body], :index_column =&gt; :all_text,
  :sync =&gt; 'ON COMMIT', :index_column_trigger_on =&gt; [:created_at, :updated_at]

And you can even create index on multiple tables by providing SELECT statements which should be used to fetch necessary columns from related tables:

add_context_index :posts,
  [:title, :body,
  # specify aliases always with AS keyword
  &quot;SELECT comments.author AS comment_author, comments.body AS comment_body FROM comments WHERE comments.post_id = :id&quot;
  :name =&gt; 'post_and_comments_index',
  :index_column =&gt; :all_text,
  :index_column_trigger_on =&gt; [:updated_at, :comments_count],
  :sync =&gt; 'ON COMMIT'
# search in any table columns
Post.contains(:all_text, 'word')
# search in specified column
Post.contains(:all_text, &quot;aaa within title&quot;)
Post.contains(:all_text, &quot;bbb within comment_author&quot;)

In terms of Oracle Text performance in most cases it is good enough (typical response in not more that hundreds of milliseconds). But from my experience it is still slower compared to dedicated full text search engines like Sphinx. So in case if Oracle Text performance is not good enough (if you need all search operations return in tens of milliseconds) then you probably need to evaluate dedicated search engines like Sphinx or Lucene.

Other changes

Please see change history file or commit list to see more detailed list of changes in this version.


As always you can install Oracle enhanced adapter on any Ruby platform (Ruby 1.8.7 or Ruby 1.9.1/1.9.2 or JRuby) with

gem install activerecord-oracle_enhanced-adapter

If you have any questions please use discussion group or report issues at GitHub or post comments here.


June 17, 2010

Please vote for my Ruby session proposals at Oracle OpenWorld

Filed under: oracle,oracle-enhanced,pl/sql,rails,ruby — Raimonds Simanovskis @ 10:32 am

oow2010.pngI am trying to tell more people at Oracle OpenWorld about Ruby and Rails and how it can be used with Oracle database. Unfortunately my session proposals were rejected by organizers but now there is a second chance to propose sessions at mix.oracle.com and top voted sessions will be accepted for conference. But currently my proposed sessions do not have enough votes :(

I would be grateful if my blog readers and Ruby on Oracle supporters would vote for my sessions Fast Web Applications Development with Ruby on Rails on Oracle and PL/SQL Unit Testing Can Be Fun!.

You need to log in to mix.oracle.com with your oracle.com login (or you should create new one if you don’t have it). And also you need to vote for at least one more session as well (as votes are counted if you have voted for at least 3 sessions). Voting should be done until end of this week (June 20).

And if you have other oracle_enhanced or ruby-plsql users in your
organization then please ask their support as well :)

Thanks in advance!

February 24, 2010

ActiveRecord Oracle enhanced adapter version 1.2.4

Filed under: oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 3:23 pm

I have released maintenance version of ActiveRecrod Oracle enhanced adapter with some bug fixes and some new features. This is the last maintenance version for Rails 2, I have already done majority of work to support also Rails 3 in next adapter versions, but that deserves another post when it will be ready :).

Detailed changes can be found in change history file and commit log, here I will point out the main changes.

Schema and structure dump

There are several improvements in schema (rake db:schema:dump) and structure dump (rake db:structure:dump) tasks. Now structure dump is improved to contain all schema objects in SQL statements format.

Also db:test:purge rake task (which is run before recreating test schema when running rake test or rake spec) is changed that it will delete all schema objects from test schema – including also views, packages, procedures and functions which are not recreated from schema.rb. So if you need to have additional database objects in your schema besides tables, indexes, sequences and synonyms (which are dumped in schema.rb) then you need to recreate them after standard rake task db:schema:load is run. Here is example how to execute any additional tasks after db:schema:load (include this in some .rake file in lib/tasks directory):

namespace :db do
  namespace :schema do
    task :load do
    task :create_other_objects do
      # include code here which creates necessary views, packages etc.

Additional options for schema definition methods

You can pass :temporary => true option for create_table method to create temporary tables.

You can use :tablespace => “tablespace name” option for add_index method to create index in non-default Oracle tablespace that is specified for user (e.g. if it is requested by your DBA for performance reasons). You can also define function based indexes using add_index and they will be correctly dumped in schema.rb.

Savepoints and nested ActiveRecord transactions

oracle_enhanced adapter now supports ActiveRecord nested transactions using database savepoints.

ruby-oci8 version

As I am using and testing oracle_enhanced adapter just with ruby-oci8 2.0.3 then I have made this as precondition (if you use MRI 1.8 or 1.9). So if you haven’t yet upgraded to latest ruby-oci8 version then please do so before upgrading to oracle_enhanced 1.2.4.

JNDI connection support

If you are using oracle_enhanced with JRuby then now you can also use JNDI database connections – please see this issue with comments to see some examples.


As always you can install Oracle enhanced adapter on any Ruby platform (Ruby 1.8.6 / 1.8.7 or Ruby 1.9.1 or JRuby) with

gem install activerecord-oracle_enhanced-adapter

If you have any questions please use discussion group or post comments here.

September 28, 2009

New features in ActiveRecord Oracle enhanced adapter version 1.2.2

Filed under: jruby,oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 7:55 pm

During the last months many new features have been implemented for ActiveRecord Oracle enhanced adapter which are now included in Oracle enhanced adapter version 1.2.2. You can find full list in change history file, here I will tell about the main ones.


Now Oracle enhanced adapter has improved RDoc documentation for all public methods. So you can go to RDoc documentation of installed gem or go and view published documentation on-line.

Schema definition

There are many new features in schema definition methods that you can use in migration files:

  • When you use add_index then ActiveRecord is automatically generating index name using format index_table_name_on_column1_and_column2_… which previously could cause Oracle errors as Oracle identifiers should be up to 30 characters long. Now default index names are automatically shortened down to 30 or less characters (of course you can always use also :name option to specify shortened version by yourself).
  • Now adapter is ignoring :limit option for :text and :binary columns (as in Oracle you cannot specify limit for CLOB and BLOB data types). Previously it could cause errors if you tried to migrate Rails application from e.g. MySQL where :text and :binary columns could have :limit in schema definition.
  • If you define :string column with :limit option then it will define VARCHAR2 column with size in characters and not in bytes (this makes difference if you use UTF-8 with language where one character might be stored as several bytes). This is expected behavior from ActiveRecord that you define maximum string size in UTF-8 characters.
  • Now you can use add_foreign_key and remove_foreign_key to define foreign key constraints in migrations (see RDoc documentation for details). Syntax and some implemenatation for foreign key definition was taken from foreigner Rails plugin as well as some ideas taken from active_record_oracle_extensions plugin.
  • add_foreign_key definitions will be also extracted in schema.rb by rake db:schema:dump task. Therefore they will be also present in test database when you will recreate it from schema.rb file.
  • Foreign keys are also safe for loading of fixtures (in case you are still using them instead of factories :)). disable_referential_integrity method is implemented for Oracle enhanced adapter which is called by ActiveRecord before loading fixtures and which disables all currently active foreign key constraints during loading of fixtures.
  • You can use add_synonym and remove_synonym to define database synonyms to other tables, views or sequences. add_synonym definitions will also be extracted in schema.rb file.
  • It is possible to create tables with primary key trigger. There will be no difference in terms how you would create new records in such table using ActiveRecord but in case you have also need to do direct INSERTs into the table then it will be easier as you can omit primary key from INSERT statement and primary key trigger will populate it automatically from corresponding sequence.
  • ActiveRecord schema dumper is patched to work correctly when default table prefixes or suffixes are used – they are now removed from schema.rb dump to avoid duplicate prefixes and suffixes when recreating schema from schema.rb.

Legacy schema support

Some features which can support “weird” legacy database schemas:

  • If you are using ActiveRecord with legacy schema which have tables with triggers that populate primary key triggers (and not using default Rails and Oracle enhanced adapter conventions) then you can use set_sequence_name :autogenerated in class definition to tell adapter to omit primary key value from INSERTs.
  • You can use ActiveRecord also with tables that you can access over database link. To do that you need to define local synonym to remote table (and also remote sequence if you want to insert records as well) and then use local synonym in set_table_name in class definition. Previously adapter could not get remote table columns, now it will get table columns also over database link.
    But still you cannot specify remote table (like “table_name@db_link”) directly in set_table_name as table_name will be used as column prefix in generated SQL statements where “@db_link” will not be valid syntax.
    And when you define local synonyms then please use the new add_synonym feature :)

Connection options

  • cursor_sharing option default value is changed from “similar” to “force” – please read explanation in discussion group post what it is and why the new default value is recommended choice.
  • When using JRuby and JDBC you can set TNS_ADMIN environment variable to tnsnames.ora directory and then use TNS database alias in database.yml file (specify just database: option and remove host: option). This might be useful for more complex TNS connection definitions, e.g. connection to load balanced Oracle RAC.
  • Adapter will not raise error if it cannot locate ojdbc14.jar file. So either put it in $JRUBY_HOME/lib or ensure that it will be loaded by application server. Would love to hear feedback from people who are using this adapter with JRuby to find out if this behaves well now :)


  • Now you can get PL/SQL debugging information into your ActiveRecord log file. Use dbms_output.put_line in your PL/SQL procedures and functions (that are called from ActiveRecord models) and in your ActiveRecord model use connection.enable_dbms_output and connection.disable_dbms_output around your database calls to get dbms_output logging information into ActiveRecord log file. But please use it just in development environment with debug log level as in production it would add too much overhead for each database call. And this feature also requires that you install ruby-plsql gem.

As you see this probably is the largest “point” release that I have had :) Thanks also to other contributors which patches were included in this release.

As always you can install Oracle enhanced adapter on any Ruby platform (Ruby 1.8.6 / 1.8.7 or Ruby 1.9.1 or JRuby) with

gem install activerecord-oracle_enhanced-adapter

If you have any questions please use discussion group or post comments here.

March 23, 2009

ActiveRecord Oracle enhanced adapter also on JRuby and Ruby 1.9

Filed under: jruby,oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 1:01 am

So far if you wanted to use Ruby on Rails on Oracle database you needed to use different adapters depending on the Ruby platform that you wanted to use. If you used original MRI (Matz Ruby interpreter) 1.8.6 then hopefully you were using Oracle enhanced adapter. But if you wanted to use JRuby then you needed to use JDBC adapter that is maintained by JRuby team (and which sometimes might work differently than Oracle enhanced adapter). And if you wanted to use new Ruby 1.9.1 then you were out of luck as no adapter supported it.

Therefore I wanted to announce great news that ActiveRecord Oracle enhanced adapter 1.2.0 is released and it supports all three major Ruby platforms!

  • Use Oracle enhanced adapter on MRI 1.8.6 with ruby-oci8 1.0.x library or gem
  • Use Oracle enhanced adapter on JRuby (so far tested with 1.1.6) with JDBC Oracle driver
  • Use Oracle enhanced adapter on Ruby/YARV 1.9.1 with ruby-oci8 2.0 library or gem

This provides you with much more flexibility to develop on one Ruby platform but deploy on another and on all three platforms you can use the same additional functionality that Oracle enhanced adapter provides on top of standard ActiveRecord functionality.

And during testing of Oracle enhanced adapter on all platforms additional milestone was achieved – Oracle enhanced adapter passes 100% ActiveRecord unit tests! But to be honest I need to tell that I needed to patch quite many unit tests for Oracle specifics as not all SQL that runs on MySQL is also valid on Oracle. I published my patched branch of ActiveRecord unit tests at my GitHub fork of Rails – you can clone the repository and verify by yourself.

So please try out new version of Oracle enhanced adapter on any Ruby platform:

gem install activerecord-oracle_enahnced-adapter

If you have any questions please use discussion group or post comments here. In nearest future I will also add more instructions how to install Oracle enhanced adapter on JRuby and Ruby 1.9.1 at GitHub wiki page.

January 3, 2009

More information sources on ActiveRecord Oracle enhanced adapter

Filed under: oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 11:51 pm

I’m glad to see that there are many users of ActiveRecord Oracle enhanced adapter and therefore comments in this blog is not anymore the best way how to communicate with Oracle enhanced adapter users. Therefore I created several other information exchange places which I hope will be more effective.

The latest addition is wiki pages on GitHub where I put usage description and examples as well as some troubleshooting hints that previously were scattered in README file and different blog posts. This is the first place where to look for information about Oracle enhanced adapter. And if you are GitHub user then you can correct mistakes or add additional content also by yourself.

If you have some question or you would like to discuss some feature then you can use Google discussion group. I will use this discussion group also for new release announcements as well so subscribe to it if you would like to get Oracle enhanced adapter news.

If you would like to report some bug or new feature (and patch would be greatly appreciated) then please use Lighthouse issue tracker.

And source code of Oracle enhanced adapter is still located in Github repository. If you are GitHub user then you can watch it or even fork it and experiment with some new features.

And BTW I just released Oracle enhanced adapter version 1.1.9 with some new features and it has been also tested with latest Rails 2.2 release.

September 26, 2008

OpenWorld unconference presentation about Rails on Oracle

Filed under: oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 2:09 am

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 :)

September 6, 2008

Oracle enhanced adapter presentation at RejectConf in Berlin

Filed under: oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 3:05 pm

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.

July 27, 2008

Latest additions to Oracle enhanced adapter

Filed under: oracle,oracle-enhanced,rails,ruby — Raimonds Simanovskis @ 9:11 pm

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

July 10, 2008

Custom ActiveRecord create, add and delete methods for legacy databases

Filed under: oracle,oracle-enhanced,pl/sql,rails,ruby — Raimonds Simanovskis @ 7:08 pm

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);

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
          :p_first_name => first_name,
          :p_last_name => last_name,
          :p_hire_date => hire_date,
          :p_salary => salary,
          :p_employee_id => nil
      # return value is ignored
      set_update_method do
          :p_employee_id => id,
          :p_first_name => first_name,
          :p_last_name => last_name,
          :p_hire_date => hire_date,
          :p_salary => salary
      # return value is ignored
      set_delete_method do
          :p_employee_id => id

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.first_name = "Second"

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.

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