为什么我的 rails db:create 不工作？答案

【问题标题】：Why is my rails db:create not working?为什么我的 rails db:create 不工作？
【发布时间】：2017-05-25 18:01:15
【问题描述】：

我在这里遵循了类似的文档，但我承认我不确定它们是否适用于这种情况，尤其是当我在 Rails 5 中工作时。所以我创建了一个 Rails API 框架，现在我尝试运行：

rails db:create

我得到这个错误：

could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
Couldn't create database for {"adapter"=>"postgresql", "encoding"=>"unicode", "pool"=>5, "database"=>"freelance_camp_documents_development"}
rails aborted!

我确实检查了 postgresql 是否在本地运行：

ldco2016@DCortes-MacBook-Pro-3 ~/Projects/freelance_camp_documents (master)$ brew services start postgresql
Service `postgresql` already started, use `brew services restart postgresql` to restart.

过去的文档引用了 config/database.yml 文件，这里是我的：

# 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: freelance_camp_documents_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: freelance_camp_documents

  # 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: freelance_camp_documents_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: freelance_camp_documents_production
  username: freelance_camp_documents
  password: <%= ENV['FREELANCE_CAMP_DOCUMENTS_DATABASE_PASSWORD'] %>

这是gemfile：

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', '~> 5.0.1'
# Use postgresql as the database for Active Record
gem 'pg', '~> 0.18'
# Use Puma as the app server
gem 'puma', '~> 3.0'
# 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

# Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible
# gem 'rack-cors'

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
  gem 'listen', '~> 3.0.5'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

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

【问题讨论】：

标签： ruby-on-rails postgresql

【解决方案1】：

我猜问题是因为您在 database.yml 中注释了您的主机和端口。

请尝试使用以下示例配置来检查它是否有效。

default: &default
  adapter: postgresql
  encoding: unicode
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  database: freelance_camp_documents_development
  username: postgres // default username. Please change if you created a new user for your app
  password: postgres // default password
  host: localhost
  port: 5432

【讨论】：

这篇文章中的答案为我解决了这个问题：stackoverflow.com/questions/17822974/…
太棒了。祝你今天过得愉快！！ :)

【解决方案2】：

你试试这个..

首先你只需检查你的gem 版本..

gem 'pg'

然后你可以检查你的pgusername和password..

如果您忘记了您的 username 和 password，请不要担心 :(..

你可以改变..

$ sudo -u postgres psql -c "ALTER USER postgres PASSWORD 'postgres';"
//OR
$ sudo passwd postgres

现在可以更改您的database.yml

development:
  encoding: unicode
  username: postgres
  password: postgres
  pool: 20
  timeout: 5000
  wait_timeout: 10
  min_messages: warning
  adapter: postgresql
  host: localhost
  database: auction_dev
  port: 5432

如果您遇到任何其他错误，请告诉我..

【讨论】：

【解决方案3】：

转到您的 config/database.yml 并在我的情况下获取数据库名称，数据库名称是 DevcampPortfolio_development

database: DevcampPortfolio_development

接下来，转到终端并输入：

psql -c "create database DevcampPortfolio_development owner=ubuntu"

那么，继续正常工作

【讨论】：

【解决方案4】：

好吧，首先进入你的应用目录并写入

psql

UPDATE pg_database SET datistemplate = FALSE WHERE datname = 'template1';

DROP DATABASE template1;

CREATE DATABASE template1 WITH TEMPLATE = template0 ENCODING = 'UNICODE';

UPDATE pg_database SET datistemplate = TRUE WHERE datname = 'template1';

\c template1

VACUUM FREEZE;

\q

然后正常创建你的数据库

【讨论】：