odba

ODBA is an unintrusive Object Cache system. It adresses the crosscutting concern of object storage by disconnecting and serializing objects into storage. All disconnected connections are replaced by instances of ODBA::Stub, thus enabling transparent object-loading.

• https://github.com/zdavatz/odba

To see a graphical overview of the Library please see

• https://raw.githubusercontent.com/zdavatz/odba/master/odba.jpeg

ODBA supports

• transparent loading of connected objects
• index-vectors
• transactions
• transparently fetches Hash-Elements without loading the entire Hash

DESCRIPTION:

• Object Database Access - Ruby Software for ODDB.org Memory Management
• https://dev.ywesee.com/ODBA/Index

FEATURES/PROBLEMS:

• There may still be an sql bottleneck. Has to be investigated further.
• You will need postgresql installed.
• The unit test test_clean__prefetched in test/test_cache.rb fails with Ruby 3.3/3.4 sometimes but not always
• Rework the unit tests to use a test database and less flexmock
• Rebase the library on the Sequel gem instead of ydbi/ydbd_pg

Example

You may find this code and some tests which is using this (example)[https://github.com/zdavatz/odba/blob/master/test/example.rb]

require "odba/connection_pool"

class User
  attr_accessor :first_name, :last_name
  include ODBA::Persistable
  def initialize(first_name, last_name)
    @first_name = first_name
    @last_name = last_name
  end

  def to_s
    "#{@first_name} #{@last_name}"
  end
end

class Example
  def self.db_setup
    # connect default storage manager to a relational database  on
    # our localhost using port 5435 with a user odba_test and an empty password
    ODBA.storage.dbi = ODBA::ConnectionPool.new("DBI:Pg:dbname=odba_test;host=127.0.0.1;port=5432", "odba_test", "")
    ODBA.cache.setup
  end

  def self.show_last_added_user
    res = ODBA.storage.dbi.select_all("Select count(*) from object;").first.first
    odba_id = ODBA.storage.dbi.select_one("select odba_id from object order by odba_id desc limit 1;")
    puts "show_last_added_user: We have  #{res} objects. Highest odba_id is #{odba_id}"
    first = ODBA.storage.dbi.select_one("select odba_id, name, prefetchable, extent, content from object order by odba_id desc limit 1;")
    puts "  DB-content is #{first}"
    puts "  Fetched object for odba_id #{odba_id} is #{ODBA.cache.fetch(odba_id.first)}"
  end
end

Example.db_setup
composer = User.new("Ludwig", "Van Beethoven")
composer.odba_store
Example.show_last_added_user
painter = User.new("Vincent", "Van Gogh")
painter.odba_store
scientist = User.new("Albert", "Einstein")
scientist.odba_store
Example.show_last_added_user

You will see something like

show_last_added_user: We have  2 objects. Highest odba_id is [2]
  DB-content is [2, nil, false, "User", "04086f3a09557365720b3a104066697273745f6e616d6549220b4c7564776967063a0645543a0f406c6173745f6e616d6549221256616e2042656574686f76656e063b07543a15406f6462615f70657273697374656e74543a0d406f6462615f696469073a14406f6462615f6f6273657276657273303a13406f6462615f707265666574636830"]
  Fetched object for odba_id [2] is Ludwig Van Beethoven
show_last_added_user: We have  4 objects. Highest odba_id is [4]
  DB-content is [4, nil, false, "User", "04086f3a09557365720b3a104066697273745f6e616d6549220b416c62657274063a0645543a0f406c6173745f6e616d6549220d45696e737465696e063b07543a15406f6462615f70657273697374656e74543a0d406f6462615f696469093a14406f6462615f6f6273657276657273303a13406f6462615f707265666574636830"]
  Fetched object for odba_id [4] is Albert Einstein

This example is run on each push to github via the (github action)[https://github.com/zdavatz/odba/blob/master/.github/workflows/devenv.yml]. It is based on (devenv.sh)[https://devenv.sh/], which ensures reproducability.

INSTALL:

• gem install odba

DEVELOPERS:

• Masamoi Hatakeyama
• Zeno R.R. Davatz
• Hannes Wyss (up to Version 1.0)
• Niklaus Giger (Porting to Ruby 2.x and 3.x, cleanup)

LICENSE:

• GPLv2.1