SQLFairy - The SQL Translator

I needed to convert a database schema from MySQL to SQLite and found a great tool for doing such schema conversion jobs.

# install sqlt on debian sytems with:
sudo apt-get install sqlfairy
# convert from one schema to another schema with:
sqlt -f DBI --dsn dbi:mysql:dbname --db-user root -t SQLite > sqlite.sql

The above command connects to mysql and reads the mysql schema from the connection and writes the sqlite schema to sqlite.sql. You can easily change this command for other databases. If you want to know if sqlt supports your conversion you can run:

sqlt -l
Parsers:
       Access
       DB2
       DB2-Grammar
       DBI
       DBI-DB2
       DBI-MySQL
       DBI-PostgreSQL
       DBI-SQLite
       DBI-Sybase
       Excel
       MySQL
       Oracle
       PostgreSQL
       SQLite
       Storable
       Sybase
       XML
       XML-SQLFairy
       YAML
       xSV

Producers:
       ClassDBI
       Diagram
       Dumper
       GraphViz
       HTML
       MySQL
       Oracle
       POD
       PostgreSQL
       SQLServer
       SQLite
       Storable
       Sybase
       TT-Base
       TT-Table
       TTSchema
       XML
       XML-SQLFairy
       YAML

The Parsers are needed to read the schema and the Producers are needed to write the schema.
Links
http://sqlfairy.sourceforge.net/

ri and ri_proxy

Yesterday i have written a little caching proxy script for ri. The script forwards any invocation to ri. The results are cached in a sqlite3 database. So that any subsequent calls are much faster, not fast as i wished but definitely faster.

#!/usr/bin/env ruby

require 'rubygems'

ROOT = File.dirname(__FILE__)
BASE_NAME = File.basename(__FILE__)

DB_FILE = File.join(ROOT, BASE_NAME + '.sqlite3')
DB_CONFIG = {:adapter => 'sqlite3', :timeout => 5000, :database => DB_FILE}

LOG_FILE = File.join(ROOT, BASE_NAME + '.log')

# speed up active record loading a bit
require 'active_support'
RAILS_CONNECTION_ADAPTERS = ['sqlite']

require 'active_record'
ActiveRecord::Base.logger = nil # Logger.new(LOG_FILE)
ActiveRecord::Base.establish_connection(DB_CONFIG)

class RiMethodEntry < ActiveRecord::Base
end

force = false
if !RiMethodEntry.table_exists? or force
  ActiveRecord::Schema.define(:version => 1) do
    create_table :ri_method_entries, :force => true do |t|
      t.column :name, :string, :null => false
      t.column :text, :text, :null => false
    end
    add_index :ri_method_entries, :name
  end
end

ARGV.length > 0 or raise Exception.new("No arguments found!")
name = ARGV[0]
entry = RiMethodEntry.find_by_name(name)
if entry
  puts entry.text
  exit
end

args = ARGV.collect { |a| %{"#{a}"} }
text = `ri #{args.join(" ")}`
found = text.starts_with?('-')

puts text
exit unless found

RiMethodEntry.create(:name => name, :text => text)