無法連接來自Sequel的MySQL gem

Question

當我嘗試從Sequel連接到MySQL時。我收到這些錯誤：

require 'rubygems' 
     require 'sequel' 
     DB = Sequel.connect(:adapter => 'mysql', :user => 'root', :host => 'localhost', :database => 'scanty',:password=>'xx') 
     DB.tables 
    Sequel::DatabaseConnectionError: NameError uninitialized constant Mysql::CLIENT_MULTI_RESULTS 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/adapters/mysql.rb:98:in `connect' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/database.rb:92:in `initialize' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/connection_pool.rb:166:in `call' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/connection_pool.rb:166:in `make_new' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/connection_pool.rb:153:in `available' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/connection_pool.rb:144:in `acquire' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/connection_pool.rb:143:in `synchronize' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/connection_pool.rb:143:in `acquire' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/connection_pool.rb:105:in `hold' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/database.rb:471:in `synchronize' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/adapters/mysql.rb:128:in `execute' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/dataset.rb:314:in `execute' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/adapters/mysql.rb:342:in `execute' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/adapters/mysql.rb:298:in `fetch_rows' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/dataset.rb:185:in `each' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/dataset/convenience.rb:156:in `map' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/dataset/convenience.rb:156:in `map' 
     from /opt/local/lib/ruby/gems/1.8/gems/sequel-3.2.0/lib/sequel/adapters/shared/mysql.rb:60:in `tables' 
     from (irb):6irb(main):007:0> Sequel::DatabaseConnectionError: NameErro 

Answer 1

您需要安裝原生MySQL驅動程序，純紅寶石一個與Sequel不兼容。

根據你的Ruby安裝，只是做gem install mysql可能就足夠了。但是，如果純Ruby的Ruby.rb文件已經在您的Ruby加載路徑中，那麼您需要將其從加載路徑中刪除，或在調用Sequel.connect之前使用gem('mysql')。

Answer 2

您錯過了:host=>'localhost'或任何您的主機。

此外，這僅僅是出於性能原因，您應該嘗試啓用:compress。它可以節省TON的帶寬。

http://sequel.rubyforge.org/rdoc/files/doc/opening_databases_rdoc.html

編輯：OK，如果不是東道主，也許這是一個衝突？請參閱http://groups.google.com/group/sequel-talk/browse_thread/thread/ee39640a92351f1?pli=1。另外http://www.mail-archive.com/sequel-talk@googlegroups.com/msg02275.html