如何使用Ruby作为脚本语言使用Ruby连接到Rails之外的MySql数据库

Question

Hi Im using Ruby as a scripting language. Not for web development, but to connect to a local database on my computer and manipulate it.

Id like to know how I can connect. Do I need to download/import tools? What do I need to get started?

Thanks,

---

Update

I did gem install mysql2 and ran the following ruby file

require 'mysql2'  

#my = Mysql.new(hostname, username, password, databasename)  
con = Mysql.new('localhost', 'nverma', 'something', 'ruby')  
rs = con.query('select * from contacts')  
rs.each_hash { |h| puts h['name']}  
con.close

and got the following error:-

/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext
 /kernel_require.rb:55:in `require': dlopen(/Library/Ruby/Gems/2.0.0/gems/mysql2-0.3.16/lib/mysql2 
 /mysql2.bundle, 9): Library not loaded: libmysqlclient.18.dylib (LoadError)
 Referenced from: /Library/Ruby/Gems/2.0.0/gems/mysql2-0.3.16/lib/mysql2/mysql2.bundle
 Reason: image not found - /Library/Ruby/Gems/2.0.0/gems/mysql2-0.3.16/lib/mysql2/mysql2.bundle
 from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext 
 /kernel_require.rb:55:in `require'
 from /Library/Ruby/Gems/2.0.0/gems/mysql2-0.3.16/lib/mysql2.rb:8:in `<top (required)>'
 from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext
 /kernel_require.rb:135:in `require'
 from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext
 /kernel_require.rb:135:in `rescue in require'
 from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext
 /kernel_require.rb:144:in `require'
 from sol5.rb:1:in `<main>'

Please help!

Answer 1

One option is to use the mysql2 gem:

gem install mysql2

Connect to your database:

client = Mysql2::Client.new(:host => "localhost", :username => "root")

Query the database:

results = client.query("SELECT * FROM users")

Answer 2

Looking at your update, is the Mysql class your own class? If so can you post that code also?

If not and you are trying to use mysql2 directly here, then you need instantiate the db connection the way @infused said in the other answer:

con = Mysql2::Client.new(host: "localhost", username: "root")