小编new*_*ere的帖子

如何修改PostgreSQL数据库中所有表的所有者？

我试过,ALTER TABLE * OWNER TO new_owner但它不支持星号语法.

我想在一个语句中更新PostgreSQL中的多行.有没有办法做以下的事情？

UPDATE table 
SET 
 column_a = 1 where column_b = '123',
 column_a = 2 where column_b = '345'

在我的gemfile中我有:

gem 'mysql2'

我的database.yml如下:

default: &default
  adapter: mysql2
  database: <%= ENV['db_name'] %>
  username: <%= ENV['db_user'] %>
  password: <%= ENV['db_pass'] %>
  host:     <%= ENV['db_host'] %>
  pool: 32
  socket:   <%= ENV['socket'] %>

development:
  <<: *default

production:
  <<: *default

我已经运行了两个bundle update并且bundle install我的Gemfile.lock显示了mysql2.

但是,当我运行时,我rake db:migrate在我的计算机和登台服务器上都得到了这个:

myproject.com(master)$ rake db:migrate
WARNING: Use strings for Figaro configuration. 10000012508 was converted to "10000012508".
WARNING: Use strings for Figaro configuration. 860526407370038 was converted to "860526407370038".
rake aborted!
Gem::LoadError: Specified 'mysql2' for database adapter, …

使用Postgres和Activerecord在多列中查找具有重复值的记录的最佳方法是什么？

我发现这个解决方案在这里:

User.find(:all, :group => [:first, :email], :having => "count(*) > 1" )

但它似乎不适用于postgres.我收到这个错误:

PG :: GroupingError:错误:列"parts.id"必须出现在GROUP BY子句中或用于聚合函数

我最近经历了数据库迁移过程,如下所述:

https://devcenter.heroku.com/articles/migrating-from-shared-database-to-heroku-postgres

现在我在日志中看到了许多错误,如下所示:

PGError:错误:关系被拒绝

关于我应该怎么做才能修复它的任何想法？

如何睡觉/等待一秒钟？

我能找到的最好的东西是这样的(在iex中):

IO.puts "foo" ; :timer.sleep(1); IO.puts "bar"

但是我的两个看法都没有延迟.

如何通过rails迁移创建新表,并为其添加唯一索引？

在文档中,我发现如何在创建表后为表添加索引,但是如何在同一个迁移文件中同时创建表并添加唯一索引？

由于/ var/log/secure中的以下错误(根据调试日志),我无法登录SSH:

Dec 19 18:01:05 hostname sshd[25119]: debug1: trying public key file /root/.ssh/authorized_keys
Dec 19 18:01:05 hostname sshd[25119]: debug1: Could not open authorized keys '/root/.ssh/authorized_keys': Permission denied

我在root上设置了以下权限

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys
chmod go-wrx ~

ls -lah为这些目录提供以下输出:

drwx------.   6 root root 4.0K Dec 19 17:46 root
drwx------.  2 root root 4.0K Dec 19 17:41 .ssh
-rw-------. 1 root root  416 Dec 19 17:12 authorized_keys

我知道我使用的密钥是正确的,因为我只是设置了另一台服务器没有任何问题.

我正在运行:CentOS版本6.4(最终版)

我已经添加了我的sshd配置,以防有可能导致问题的错误配置:

#       $OpenBSD: sshd_config,v 1.80 2008/07/02 02:24:18 djm Exp $

# This …

我在跑:

Chrome版本google-chrome-stable/unknown uptodate 27.0.1453.93-r200836

Debian GNU/Linux 6.0.6(挤压)32x

当我尝试运行时:

require 'watir-webdriver'
require 'headless'
headless = Headless.new
headless.start
b = Watir::Browser.new(:chrome)

我明白了:

EOFError: end of file reached
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/protocol.rb:141:in `read_nonblock'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/protocol.rb:141:in `rbuf_fill'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/protocol.rb:122:in `readuntil'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/protocol.rb:132:in `readline'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:2563:in `read_status_line'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:2552:in `read_new'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:1320:in `block in transport_request'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:1317:in `catch'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:1317:in `transport_request'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:1294:in `request'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:1287:in `block in request'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:746:in `start'
        from /usr/local/rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/net/http.rb:1285:in `request'
        from /usr/local/rvm/gems/ruby-1.9.3-p429/gems/selenium-webdriver-2.33.0/lib/selenium/webdriver/remote/http/default.rb:83:in `response_for'
        from /usr/local/rvm/gems/ruby-1.9.3-p429/gems/selenium-webdriver-2.33.0/lib/selenium/webdriver/remote/http/default.rb:39:in `request'
        from /usr/local/rvm/gems/ruby-1.9.3-p429/gems/selenium-webdriver-2.33.0/lib/selenium/webdriver/remote/http/common.rb:40:in `call'
        from /usr/local/rvm/gems/ruby-1.9.3-p429/gems/selenium-webdriver-2.33.0/lib/selenium/webdriver/remote/bridge.rb:629:in `raw_execute' …

elixir的pry可以在模块中运行私有方法吗？例如:

defmodule Test do
  require IEx

  def foo do
    IEx.pry
  end

  defp bar do
  end
end

此时呼叫bar不起作用.我对elixir很新,有什么我做错了或者为什么这是不可能的？