[Groonga-talk] [ANN] rroonga 3.0.4

[Kouhei S. <ko...@cl...>]

Hi,

Rroonga 3.0.4 has been released! Rroonga is the Ruby
bindings for groonga.

Web: http://ranguba.org/ja/#about-rroonga

About rroonga
-------------

Here are two important things by rroonga.

  1. Providing *Ruby-ish* API to use groonga.
  2. Providing *fast* operations like groonga.

They means that rroonga provides easy to use API without
decreasing groonga's speed.

About this release
------------------

In this release, rroonga supports the sub record feature
that is introduced since groonga 3.0.5. The sub record
feature is getting grouped records (= sub records) after
group operation is performed.

For example, you can display concrete items around drilldown
by genre:

  * Book (1238)
    * Ruby (29件) <- A genre
      * Programming Ruby     <- A sub record!
      * Metaprogramming Ruby <- A sub record!
      * ...
    * Python (13) <- A genre
      * ...
    * PHP (23) <- A genre
      * ...

Here is an example. See comments for details.

----
require "fileutils"

require "groonga"

db_dir = "/tmp/db"
FileUtils.rm_rf(db_dir)
FileUtils.mkdir_p(db_dir)

Groonga::Database.create(:path => "#{db_dir}/db")

# The schema for a user can bookmark one or more sites.
Groonga::Schema.define do |schema|
  schema.create_table("Users",
                      :type => :hash,
                      :key_type => :short_text) do |table|
    table.short_text("name")
  end

  schema.create_table("Bookmarks") do |table|
    table.short_text("url")
    table.reference("user")
  end
end

# Register three users.
users = Groonga["Users"]
users.add("mori", :name => "Daijiro MORI")
users.add("kou", :name => "Kouhei Sutou")
users.add("s-yata", :name => "Susumu Yata")

bookmarks = Groonga["Bookmarks"]
# Bookmarks groonga.org.
bookmarks.add(:url => "http://groonga.org/", :user => "mori")
bookmarks.add(:url => "http://groonga.org/", :user => "kou")
bookmarks.add(:url => "http://groonga.org/", :user => "s-yata")
# Bookmarks mroonga.org.
bookmarks.add(:url => "http://mroonga.org/", :user => "kou")
# Bookmarks ranguba.org.
bookmarks.add(:url => "http://ranguba.org/", :user => "kou")
bookmarks.add(:url => "http://ranguba.org/", :user => "mori")

# Groups bookmarks by user.
# The max number of sub records to be got is 2.
bookmarks.group("user", :max_n_sub_records => 2).each do |group|
  # Gets the actual value (= a user) from grouped result record.
  user = group.key
  # Displays user id (= key) and the number of sub records.
  # The number of sub records isn't effected by :max_n_sub_records => 2.
  puts "#{user.key} (#{group.n_sub_records})"
  # Displays information about each record (= a sub record).
  # A sub record is bookmark record because bookmarks table
  # is grouped.
  # The max number of sub records is 2
  # because、:max_n_sub_records => 2 restricts it.
  group.sub_records.each do |bookmark|
    puts "  #{bookmark.url}"
  end
end
# Result:
#   mori (2)
#     http://groonga.org/
#     http://ranguba.org/
#   kou (3)
#     http://groonga.org/
#     http://mroonga.org/
#   s-yata (1)
#     http://groonga.org/
#
# kou user has 3 sub records but 2 sub records are only
# displayed because :max_n_sub_records => 2 restricts it.
----

Install
-------

  % gem install rroonga

Tutorial
--------

There are a tutorial that uses irb:
  http://ranguba.org/rroonga/en/file.tutorial.html

If you are are beginner, please try it.

Here are changes since 3.0.2:
  http://ranguba.org/rroonga/ja/file.news.html#3-0-4

3.0.4: 2013-07-04
-----------------

Fixes
^^^^^

* Fixed a rroogna 3.0.3 gem package for Windows.

3.0.3: 2013-07-04
-----------------

Improvements
^^^^^^^^^^^^

* Required groonga >= 3.0.5.
* Added an error check for creating a result table of {Groonga::Table#select}.
* Added {Groonga::Operator::AND_NOT}.
* Deprecated {Groonga::Operator::BUT} because groonga deprecated it.
  Use {Groonga::Operator::AND_NOT} instead.
* Added {Groonga::Array#unblock}.
* Added @:max_n_sub_records@ option to {Groonga::Table#group}.
* Added {Groonga::Table#each_sub_record}.
* Supported groonga to Ruby conversion for vector value.
* Added @:reference => true@ option to {Groonga::Expression#define_variable}
  that defines reference type variable.
* Added {Groonga::Record#sub_records} that returns sub records for the record.
  Sub records is a {Groonga::SubRecords} instance.

Fixes
^^^^^

* Fixed {Groonga::Expression#[]} return type. It returns {Groonga::Variable}
  instead of value itself. CAUTION: It is a backward incompatible change.

Thanks,
--
kou