如何开始在Rails应用程序中使用Postgresql数据库？

Question

我已经花了几个小时在网上寻找解决方案。 Postgresql安装指南无济于事，因为我不熟悉仅使用ruby on rails与数据库进行交互并以这种方式处理它们。

通过遵循教程，我已经做了几个简单的Rails应用程序，并且仍在学习Rails。 我正在使用Windows 10，并且已将其中一些部署到Heroku，因此必须使用pg gem，因为Heroku不使用sqlite3。 但是我在几个地方读到，有必要在本地安装postgresql。 我想我已经安装了它，但是现在我迷路了。 我有一个名为pgAdmin4的软件，现在我完全不知道如何通过Rails使用Postgresql。 我使用以下命令启动了一个新应用程序以对其进行测试：

rails new postgresapp --database=postgresql

这为我设置了使用postgresql的新应用程序提供了基本的起点。 当我尝试连接到localhost3000时遇到的第一个错误是：

PG::ConnectionBad
fe_sendauth: no password supplied

Extracted source (around line #56):

    ### Convenience alias for PG::Connection.new.
    def self::connect( *args )
        return PG::Connection.new( *args )
    end

请记住，我不确定安装是否成功。 我经历了安装过程，输入了密码和所有信息，因此我认为它确实安装在某个地方。

pgAdmin上也没有显示服务器，所以我添加了一个叫做localhost的服务器。 我不确定这是否正确。

宝石文件：

source 'https://rubygems.org'

git_source(:github) do |repo_name|
  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
  "https://github.com/#{repo_name}.git"
end


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.0.6'
# Use postgresql as the database for Active Record
gem 'pg', '~> 0.18'
# Use Puma as the app server
gem 'puma', '~> 3.0'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.2'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '~> 5'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.5'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 3.0'
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platform: :mri
end

group :development do
  # Access an IRB console on exception pages or by using <%= console %> anywhere in the code.
  gem 'web-console', '>= 3.3.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

数据库

# PostgreSQL. Versions 9.1 and up are supported.
#
# Install the pg driver:
#   gem install pg
# On OS X with Homebrew:
#   gem install pg -- --with-pg-config=/usr/local/bin/pg_config
# On OS X with MacPorts:
#   gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
# On Windows:
#   gem install pg
#       Choose the win32 build.
#       Install PostgreSQL and put its /bin directory on your path.
#
# Configure Using Gemfile
# gem 'pg'
#
default: &default
  adapter: postgresql
  encoding: unicode
  # For details on connection pooling, see rails configuration guide
  # http://guides.rubyonrails.org/configuring.html#database-pooling
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  database: postgresapp_development

  # The specified database role being used to connect to postgres.
  # To create additional roles in postgres see `$ createuser --help`.
  # When left blank, postgres will use the default role. This is
  # the same name as the operating system user that initialized the database.
  #username: postgresapp

  # The password associated with the postgres role (username).
  #password:

  # Connect on a TCP socket. Omitted by default since the client uses a
  # domain socket that doesn't need configuration. Windows does not have
  # domain sockets, so uncomment these lines.
  #host: localhost

  # The TCP port the server listens on. Defaults to 5432.
  # If your server runs on a different port number, change accordingly.
  #port: 5432

  # Schema search path. The server defaults to $user,public
  #schema_search_path: myapp,sharedapp,public

  # Minimum log levels, in increasing order:
  #   debug5, debug4, debug3, debug2, debug1,
  #   log, notice, warning, error, fatal, and panic
  # Defaults to warning.
  #min_messages: notice

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: postgresapp_test

# As with config/secrets.yml, you never want to store sensitive information,
# like your database password, in your source code. If your source code is
# ever seen by anyone, they now have access to your database.
#
# Instead, provide the password as a unix environment variable when you boot
# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
# for a full rundown on how to provide these environment variables in a
# production deployment.
#
# On Heroku and other platform providers, you may have a full connection URL
# available as an environment variable. For example:
#
#   DATABASE_URL="postgres://myuser:mypass@localhost/somedatabase"
#
# You can use this database configuration with:
#
#   production:
#     url: <%= ENV['DATABASE_URL'] %>
#
production:
  <<: *default
  database: postgresapp_production
  username: postgresapp
  password: post#<%= ENV['POSTGRESAPP_DATABASE_PASSWORD'] %>

Answer 1

当您检查database.yml文件中的内容时，需要配置用户和密码 。

您将密码作为空白值。

我建议使用密码创建一个postgreSql用户并使用这些凭据

您将需要psql从终端访问postgreSql，以创建具有权限的新用户。

其中一个链接 ，您可以在网上找到更多有关此的信息。

但是你的问题是用户和他的密码

解决用户和密码问题之后，您将需要使用来自database.yml的名称创建database.yml 。

在您的database.yml数据库名称为postgresapp_development 。 您将需要创建它。 查找用于Windows的客户端，以使用在安装和创建数据库时定义的用户名和密码连接到postgreSql。

检查这个访问你服务器PostgreSQL的