Add 'script/dbconsole' -- the database analog of 'script/console'

railties/bin/dbconsole

+#!/usr/bin/env ruby
+require File.dirname(__FILE__) + '/../config/boot'
+require 'commands/dbconsole'

railties/lib/commands/dbconsole.rb

+require 'optparse'
+OptionParser.new do |opt|
+  opt.banner = "Usage: dbconsole [environment]"
+  opt.parse!(ARGV)
+  abort opt.to_s unless (0..1).include?(ARGV.size)
+end
+
+env = ENV['RAILS_ENV'] = ARGV.first || ENV['RAILS_ENV'] || 'development'
+
+def find_cmd(*commands)
+  dirs_on_path = ENV['PATH'].split(File::PATH_SEPARATOR)
+  commands += commands.map{|cmd| "#{cmd}.exe"} if RUBY_PLATFORM =~ /win32/
+  commands.detect do |cmd|
+    dirs_on_path.detect do |path|
+      File.executable? File.join(path, cmd)
+    end
+  end || abort("couldn't find matching executable: #{commands.join(', ')}")
+end
+
+
+require 'yaml'
+config = YAML::load(File.read(RAILS_ROOT + "/config/database.yml"))[env]
+
+unless config
+  abort "No database is configured for the environment '#{env}'"
+end
+
+case config["adapter"]
+when "mysql"
+  exec(find_cmd(*%w(mysql5 mysql)),
+       *({ 'host'      => '--host',
+           'port'      => '--port',
+           'socket'    => '--socket',
+           'username'  => '--user',
+           'password'  => '--password',
+           'encoding'  => '--default-character-set'
+         }.map { |opt, arg| "#{arg}=#{config[opt]}" if config[opt] }.compact +
+         [config['database']]))
+when "postgresql"
+  ENV['PGHOST']     = config["host"] if config["host"]
+  ENV['PGPORT']     = config["port"].to_s if config["port"]
+  ENV['PGPASSWORD'] = config["password"].to_s if config["password"]
+  exec(find_cmd('psql'), '-U', config["username"], config["database"])
+when "sqlite"
+  exec(find_cmd('sqlite'), config["database"])
+when "sqlite3"
+  exec(find_cmd('sqlite3'), config["database"])
+else abort "not supported for this database type"
+end