使用 ActiveRecord 时 createdb 未被识别为命令

Question

我是 Ruby 和 Web 开发的新手。我正在使用带有 Ruby 2.0 的 Windows 7 64 位，并且安装了 PostgreSQL 9.4。

我正在尝试使用 ActiveRecord 创建数据库。我检查了我的 postgresql 服务器是否正在运行，并且我进行了 bundle install 以确保我拥有所有必需的 gem。但是，当我尝试执行终端命令“bundle exec rake create:db”时，它告诉我“'createdb' 未被识别为内部或外部命令、可运行程序或批处理文件”。我还使用 --trace 执行了该命令，但它没有提供有关问题所在的更多有用输出。终端只是显示这个：

C:\Users\MH\Desktop\activerecord-template> bundle exec rake db:create
Creating activerecord-template development and test databases if they don't exist...
'createdb' is not recognized as an internal or external command, operable program or batch file.

C:\Users\MH\Desktop\activerecord-template> bundle exec rake db:create --trace
**Invoke db:create (first_time)
**Execute db:create
'createdb' is not recognized as an internal or external command, operable program or batch file.

我发现的与此问题最接近的信息位于此链接：http://bobbyong.com/blog/installing-postgresql-on-windoes/。我确实按照链接中的描述调整了 PostGreSQL 的路径，但我仍然遇到相同的 createdb 问题。我还卸载/重新安装了 PostGreSQL。我可以在 PostGreSQL 目录中看到 createdb 文件，并且 createdb 在我使用 psql 时作为命令工作，所以我不确定 ActiveRecord 到底是什么问题。

这是我的 Gemfile 中的内容：

source 'https://rubygems.org'

gem 'activerecord'
gem 'pg'

gem 'rspec'
gem 'faker'

gem 'rake'

这是我的 Rakefile 中的内容：

    require 'rake'
    require 'rspec/core/rake_task'
    require 'active_support'
    require 'active_support/core_ext'

    require_relative 'config'

    namespace :db do
      desc "Drop, create, and migrate the database"
      task :reset => [:drop, :create, :migrate]

      desc "Create #{APP_NAME} databases"
      task "create" do
        puts "Creating #{APP_NAME} development and test databases if they don't exist..."
        system("createdb #{DB_NAME} --username #{DB_USERNAME} -w --no-password && createdb #{TEST_DB_NAME} --username #{DB_USERNAME} -w --no-password")
      end

      desc "Drop #{APP_NAME} databases"
      task "drop" do
        puts "Dropping #{APP_NAME} development and test databases..."
        system("dropdb #{DB_NAME} && dropdb #{TEST_DB_NAME}_test")
      end

      desc "Migrate the database"
      task "migrate" do
        ActiveRecord::Migrator.migrations_paths << File.dirname(__FILE__) + 'db/migrate'
        ActiveRecord::Migration.verbose = true
        ActiveRecord::Migrator.migrate(ActiveRecord::Migrator.migrations_paths, nil)
      end

      desc "Populate the database with sample data"
      task "seed" do
        require APP_ROOT.join('db', 'seeds.rb')
      end
    end

    namespace :generate do
      desc "Create a database migration\n rake generate:migration NAME=create_people"
      task :migration do
        unless ENV.has_key?('NAME')
          raise "Must specify NAME for migration, e.g. rake generate:migration NAME=create_people"
        end

        migration_name = ENV['NAME']
        class_name = migration_name.camelize
        timestamp = Time.now.strftime('%Y%m%d%H%M%S')
        filename = "#{timestamp}_#{migration_name}.rb"
        path = APP_ROOT.join('db', 'migrate', filename)

        if File.exist?(path)
          raise "ERROR! File '#{path}' already exists"
        end

        puts "Creating migration at #{path}"
        File.open(path, 'w+') do |f|
          f.write("class #{class_name} < ActiveRecord::Migration\n\tdef change\n\n\tend\nend")
        end
      end
    end

    desc 'Start IRB with application environment loaded'
    task "console" do
      exec "irb -r./config"
    end

    desc "Run the specs"
    RSpec::Core::RakeTask.new(:spec)
    task :default  => :specs

    # Will this not work?
    #desc "Run the specs"
    #task 'specs' do
    #  exec "rspec spec"
    #end

这是我的 config.rb 文件中的内容：

require 'pathname'
require 'pg'
require 'active_record'
require 'logger'

## Load all files and configure the db

APP_ROOT = Pathname.new(File.expand_path(File.dirname(__FILE__)))

APP_NAME = APP_ROOT.basename.to_s

DB_PATH  = APP_ROOT.join('db', APP_NAME + "_development.db").to_s

DB_NAME = APP_NAME + "_development.db"

TEST_DB_NAME = APP_NAME + "_test.db"

DB_USERNAME = 'postgres'

DB_PASSWORD = 

if ENV['DEBUG']
  ActiveRecord::Base.logger = Logger.new(STDOUT)
end


Dir[APP_ROOT.join('models', '*.rb')].each do |model_file|
  filename = File.basename(model_file).gsub('.rb', '')
  autoload ActiveSupport::Inflector.camelize(filename), model_file
end

ActiveRecord::Base.establish_connection :adapter  => 'postgresql',
                                        :database => DB_NAME,
                                        :host => 'localhost',
                                        :username => DB_USERNAME,
                                        :password => DB_PASSWORD

Answer 1

如果终端命令“bundle exec rake create:db”产生错误“'createdb' is not Recognized as an internal or external command, operable program or batch file.”，这意味着 ActiveRecord 无法找到 createdb .exe 在 PostgreSQL 目录中。

您必须将 PostgreSQL bin 和 lib 文件夹附加到您的路径环境变量中，如下所述：http://bobbyong.com/blog/installing-postgresql-on-windoes/

请注意，将 bin 路径放在 lib 路径之前很重要，否则 ActiveRecord 仍然无法在 bin 路径中找到 createdb.exe。还要确保重新启动您的命令终端，以便对环境变量的任何更改都可以生效。